Southwest Research-Extension Center Field Day 2007

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Troy Dumler-Extension Agricultural
Economist. Troy received his B.S. and M.S. from Kansas State University. He joined the staff in 1998. His extension program primarily focuses on crop production and machinery economics.  .

Southwest Research-Extension Center
December received a record-shattering monthly total of 3.82" of precipitation, breaking the previous monthly record of 2.08" set in 93. This gave a yearly total of 9.02", which was .58" above normal, even though only three months had above-normal precipitation. October was the wettest month, with 4.05". The largest single amount of precipitation was 2.56" on October 27. February was the driest month, with 0.0" of precipitation. Snowfall for the year totaled 37.6": 2.8" in January, 0." in February, 7." in March, 2.3" in November, and 25.3" in December, for a total of twenty-three days of snow cover. The year ended with twelve days of snow cover on December 20-3, which was the longest consecutive period.
The mean air temperature was above normal for 0 months. February was normal, January had the greatest departure above normal (.°), and September was below normal (-3.3°). There were 22 days of 00° temperatures or above (twelve more than normal). There were 75 days of 90° or above temperatures (3 more than normal). The last day of 32° or less in the spring (April 26) was 0 days earlier than normal, and the first day of 32° or less in the fall (October 3) was 0 days later than normal. This produced a frost-free period of 70 days, or 20 days more than normal.
Open-pan evaporation for the period April through September totaled 78.63 inches, which was 7.98 inches above normal. The average wind speed for the same period was 4.8 mph, which was 0.7 mph less than normal.

INTRODUCTION
This study was initiated in 96 to determine responses of continuous grain sorghum grown under flood irrigation to N, P, and K fertilization. The study was conducted on a Ulysses silt loam soil with an inherently high K content. The irrigation system was changed from flood to sprinkler in 200.

PROCEDURES
Fertilizer treatments initiated in 96 were N rates of 0, 40, 80, 20, 60, and 200 lb N/a without P and K; with 40 lb P 2 O 5 /a and zero K; and with 40 lb P 2 O 5 /a and 40 lb K 2 O /a. All fertilizers were broadcast by hand in the spring and incorporated prior to planting. The soil is a Ulysses silt loam. Sorghum (Pioneer 844 in 997 and Pioneer 8500/8505 from  was planted in late May or early June. Irrigation was used to minimize water stress. Furrow irrigation was used through 2000 and sprinkler irrigation since 200. The center two rows of each plot were machine harvested after physiological maturity. Grain yields were adjusted to 2.5% moisture.

LONG-TERM NITROGEN AND PHOSPHORUS FERTILIZATION ON YIELD OF IRRIGATED CORN
by Alan Schlegel lb P 2 O 5 /a and zero K; and with 40 lb P 2 O 5 /a and 40 lb K 2 O/ a. In 992, the treatments were changed with the K variable being replaced by a higher rate of P (80 lb P 2 O 5 /a). All fertilizers were broadcast by hand in the spring and incorporated prior to planting. The soil is a Ulysses silt loam. The corn hybrids were Pioneer 3225 (997), Pioneer 3395IR (998), Pioneer 33A4 (2000), Pioneer 33R93 (200 and 2002), DeKalb C60-2 (2003), Pioneer 34N45 (2004 and 2005), and Pioneer 34N50 (2006) planted at approximately 30-32,000 seeds/a in late April or early May. Hail damaged the 2005 and 2002 crops and destroyed the 999 crop. The corn was irrigated to minimize water stress. Furrow irrigation was used through 2000 and sprinkler irrigation since 200. The center two rows of each plot were machine harvested after physiological maturity. Grain yields were adjusted to 5.5% moisture.

RESULTS
Corn yields in 2006 were similar to the 0-year average (Table ). Nitrogen alone increased yields up to 70 bu/a, while P alone increased yields only 30 bu/a. However, N and P applied together increased corn yields up to 60 bu/a. Only 20 lb N/a with P was required to obtain maximum yields. Over the past 0 years, 20 lb N/a with P has produced 95% of maximum yield. Corn yields (averaged across all N rates) were 3 bu/a greater with 80 P 2 O 5 / a than with 40 lb/a in 2006, which is considerably greater than the 0-year average. Also, with N rates of 20 lb N/a or greater in 2006 the higher P rate increased yields more than 20 bu/a. SUMMARY Long-term research shows that phosphorus (P) and nitrogen (N) fertilizer must be applied to optimize production of irrigated corn in western Kansas. In 2006, N and P applied alone increased yields about 70 and 30 bu/a, respectively; however, N and P applied together increased yields up to 60 bu/a. Averaged across the past 0 years, corn yields were increased up to 25 bu/a by N and P fertilization. Application of 120 lb N/a (with P) was sufficient to produce maximum yields in 2006, which was slightly more than the 0-year average. Phosphorus increased corn yields in 2006 an average of more than 00 bu/a when applied with at least 20 lb N/a. Application of 80 lb P 2 O 5 /a instead of 40 lb/a increased yields 20 bu/a when applied with at least 20 lb N/a.

INTRODUCTION
This study was initiated in 96 to determine responses of continuous corn and grain sorghum grown under flood irrigation to N, P, and K fertilization. The study was conducted on a Ulysses silt loam soil with an inherently high K content. No yield benefit to corn from K fertilization was observed in 30 years and soil K levels remained high, so the K treatment was discontinued in 992 and replaced with a higher P rate. PROCEDURES Initial fertilizer treatments in 96 were N rates of 0, 40, 80, 20, 60, and 200 lb N/a without P and K; with 40   3  54  39  79  67  49  42  84  0  40  79  55  52  43  43  95  97  60  68  77  0  80  83  55  53  48  44  93  98  5  72  78  40  0  86  76  50  7  47  07  92  63  56  83  40  40

SUMMARY
Animal wastes are routinely applied to cropland to recycle nutrients, build soil quality, and increase crop productivity. This study evaluates established best management practices for land application of animal wastes on irrigated corn. Swine waste (effluent water from a lagoon) and cattle waste (solid manure from a beef feedlot) have been applied annually since 999 at rates to meet estimated corn P requirements, corn N requirements, or a rate double the N requirement. Other treatments were N fertilizer (60, 20, and 80 lb N/a) and an untreated control. Corn yields were increased by application of animal wastes and N fertilizer. Over-application of cattle manure has not had a negative effect on corn yield. For swine effluent, over-application has not reduced corn yields except in 2004, when the effluent had much greater salt concentration than in previous years, which caused reduced germination and poor early growth.

INTRODUCTION
This study was initiated in 999 to determine the effect of land application of animal wastes on crop production and soil properties. The two most common animal wastes in western Kansas were evaluated; solid cattle manure from a commercial beef feedlot and effluent water from a lagoon on a commercial swine facility.

PROCEDURES
The rate of waste application was based on the amount needed to meet the estimated crop P requirement, crop N requirement, or twice the N requirement (Table ). The Kansas Department of Agriculture Nutrient Utilization Plan form was used to calculate animal waste application rates. Expected corn yield was 200 bu/a. The allowable P application rates for the P-based treatments were 05 lb P2O5/a because soil test P levels were less than 50 ppm Mehlich-3 P. The N recommendation model uses yield goal less credits for residual soil N and previous manure applications to estimate N requirements. For the N-based swine treatment, the residual soil N levels after harvest in 200, 2002, and 2004 were great enough to eliminate the need for additional N the following year. Therefore, no swine effluent was applied to the xN treatment in 2002, 2003, or 2005 or to the 2xN requirement treatment, because it is based on x treatment (Table ). The same situation occurred for the N-based treatments using cattle manure in 2003. Nutrient values used to calculate initial applications of animal wastes were 7.5 lb available N and 25.6 lb available P 2 O 5 per ton of cattle manure and 6. lb available N and .4 lb available P 2 O 5 per 1000 gallons of swine effluent (actual analysis of animal wastes as applied varied somewhat from the estimated values, Table 2). Subsequent applications were based on previous analyses. Other nutrient treatments were three rates of N fertilizer (60, 20, and 80 lb N/a) along with an untreated control. The N fertilizer treatments also received a uniform application of 50 lb/a of P 2 O 5 . The experimental design was a randomized complete block with four replications. Plot size was 2 rows wide by 45 ft long.
The study was established in border basins to facilitate effluent application and flood irrigation. The swine effluent was flood-applied as part of a pre-plant irrigation each year. Plots not receiving swine effluent were also irrigated at the same time to balance water additions. The cattle manure was hand-broadcast and incorporated. The N fertilizer (granular NH 4 NO 3 ) was applied with a 0-foot fertilizer applicator (Rogers Mfg.). The entire study area was uniformly irrigated during the growing season, with flood irrigation in 999-2000 and sprinkler irrigation in 200-2006. The soil is a Ulysses silt loam. Corn was planted at about 33,000 seeds/a in late April or early May each year. Grain yields are not reported for 999 because of severe hail damage. Hail also damaged the 2002 and 2005 crop. The center four rows of each plot were machine harvested after physiological maturity with yields adjusted to 5.5% moisture.

RESULTS
Corn yields were increased by all animal waste and N fertilizer applications in 2006, as has been the case for all years except in 2002, when yields were greatly reduced by hail damage (Table 3). The type of animal waste affected yields in five of the seven years with higher yields from cattle manure than from swine effluent. Averaged across the seven years, corn yields were 4 bu/a greater follow-ing application of cattle manure than swine effluent on an N application basis. Over-application (2xN) of cattle manure has had no negative impact on grain yield in any year. However, over-application of swine effluent reduced yields in 2004 because of considerably greater salt content (two to three times greater electrical conductivity than any previ-ous year) causing germination damage and poor stands. No adverse residual effect from the over-application has been observed.    2000  2001  2002  2003  2004  2005  2006  Mean  ---------------------bu/acre ---------------------Cattle manure  P  97  92  9  74  24  43  236  82  N  95  82  90  75  243  47  27  78  2 X N  95  85  92  8  244  55  23  8  Swine effluent  P  89  62  74  68  73  35  89  wheat-corn-soybean-fallow). All rotations are grown using no-till practices except for wheat-fallow, which is grown using reduced tillage. All phases of each rotation are present each year. Plot size is a minimum of 00 by 450 feet. In most instances, grain yields were determined by harvesting the center 60 feet (by entire length) of each plot with a commercial combine and determining grain weight in a weigh-wagon. If harvesting the entire plot was not feasible, then smaller sections of each plot were harvested with a plot combine.

RESULTS AND DISCUSSION
Grain yields of winter wheat in 2006 were below average in 2006 (Table ). Corn yields were also poor. Precipitation was below normal each month from January through May (3.28 inches compared to normal of 6.24 inches). June precipitation was slightly above average (3.05 inches compared to the average of 2.62 inches), while July and August rainfall were below average. Sorghum yields in the WSF rotation were about near-average at 50 bu/a while sorghum following corn yielded less than 0 bu/a. Soybeans were severely damaged by rabbits and yielded only 2 bu/a. Sunflower yields were greater following corn than wheat.
In most years, wheat yields are lower following sunflower than sorghum (Table 2). Averaged across the past 2 years, wheat yields were 9 bu/a greater following sorghum than sunflower. For the same time period, wheat yields were 4 bu/a greater in WF than WSF.
In eight of the past 2 years, grain sorghum has yielded more than corn when both were planted no-till into wheat stubble (Table 3). Averaged across the 2 years, grain sorghum yields have been 8 bu/a, or 50% greater than corn yields. In seven of the past nine years, grain sorghum yields have been greater following wheat than corn (averaged averaging 6 bu/a, or 50% greater yields).
This research project receives support from the Ogallala Aquifer Initiative.

SUMMARY
A large-scale rain-fed cropping systems research and demonstration project evaluated four summer crops (corn, grain sorghum, sunflower, and soybean) along with winter wheat in crop rotations varying in length from two to four years. The objective of the study is to identify cropping systems that enhance and stabilize production in rainfed cropping systems to optimize economic crop production. Lack of precipitation during the winter and spring depressed wheat yields in 2006. Wheat yields were less smaller following sunflower than as opposed to sorghum in three-year rotations. This trend has been seen in most years, with an average of 9 bu/a lower wheat yields following sunflower than as opposed to sorghum. In 2006, grain sorghum yields were 4 bu/a greater following wheat than they were following corn. In 2006, corn yields were reduced by below normal precipitation during pollination. Averaged across the past 2 years, sorghum has yielded 8 bu/a more than corn when both planted no-till into wheat stubble.

INTRODUCTION
The purpose of this project is to research and demonstrate several multi-crop rotations that are feasible for the region, along with several alternative systems that are more intensive than two-or three-year rotations. There are two objectives. The first is to enhance and stabilize production of rain-fed cropping systems through the use of multiple crops and rotations using best management practices to optimize capture and utilization of precipitation for economic crop production. The second is to enhance adoption of alternative rain-fed cropping systems that provide optimal profitability.
Last 2 rows are yields for corn and grain sorghum in a wheat-corn-grain sorghum-fallow rotation.

SUMMARY
Grain yields of wheat and grain sorghum increased with decreased tillage intensity in a wheat-sorghum-fallow (WSF) rotation. Averaged across the past 6 years, no-till wheat yields were 4 bu/a greater than with reduced tillage and 8 bu/acre greater than with conventional tillage. In 2006, wheat yields were very low but no-till produced 6 bu/a while reduced or conventional tillage resulted in almost complete failure. Grain sorghum yields were also low in 2006; like no-till wheat, no-till sorghum yielded more (29 bu/a) while conventional or reduced tillage sorghum yielded less than 5 bu/a. Averaged across the past 6 years, no-till sorghum yields were 4 bu/a greater than with reduced tillage and 33 bu/acre greater than with conventional tillage. Averaged across the past six years, sorghum yields were 25 bu/a greater with long-term no-till compared to short-term no-till.

PROCEDURES
Research on different tillage intensities in a WSF rotation at the K-State Southwest Research-Extension Center at Tribune was initiated in 99. The three tillage intensities are conventional (CT), reduced (RT), and no-till (NT). The CT system was tilled as needed to control weed growth during the fallow period. On average, this resulted in 4 to 5 tillage operations per year, usually with a blade plow or field cultivator. The RT system originally used a combination of herbicides (one or two spray operations) and tillage (two to three tillage operations) to control weed growth during the fallow period. However, in 200, the RT system was changed to using no-till from wheat harvest through sorghum planting and conventional tillage from sorghum harvest to wheat planting. The NT system exclusively used herbicides to control weed growth during the fallow period. All tillage systems used herbicides for in-crop weed control.

RESULTS AND DISCUSSION
Conservation tillage increased wheat yields (Table  ). On average, wheat yields were 8 bu/a higher for NT (36 bu/a) than for CT (28 bu/a). Wheat yields for RT were 4 bu/a greater than CT. In 2006, wheat yields were severely reduced by dry conditions during the spring.
The yield benefit from reduced tillage was greater for grain sorghum than for wheat. Grain sorghum yields for RT averaged 2 bu/a more than CT, while NT averaged 4 bu/a more than RT (Table 2). In 2006, sorghum yields were 25 bu/a greater with NT than either RT or CT. Since the RT sorghum was no-till from wheat harvest to sorghum planting there evidently is a yield benefit from long-term no-till. Since 200 (when the RT system was changed), sorghum yields in long-term no-till averaged 25 bu/a greater than with short term no-till (the RT system), an increase of 95%.

SUMMARY
Research on skip row planting of dryland corn was initiated at the near Tribune in 2004. The objective was to determine whether some pattern of skipping rows would improve drought tolerance of dryland corn. The planting arrangements were to plant one row and skip one (PS); plant two rows and skip one (P2S); plant two rows and skip two (P2S2); and plant every row (P-All). Target plant populations were 0,000, 5,000, and 20,000 plants per acre. Corn was no-till planted into standing wheat stubble in early May of each year from 2004 to 2006. Corn yields were above average in 2004 and 2005, with yields above 90 bu/a in both years. In these high-yielding years, corn planted every row at a plant population of 5,000 acreproduced the highest yields; however, the PS arrangement produced similar yields. The other two planting arrangements (P2S and P2S2) tended to reduce yield. In 2006, yields were less than 50 bu/a and corn planted every row at 5,000 plants/a again produced the best yields, although similar yields were obtained with all other planting arrangements. Plant population had more impact on yield that skip row planting. In 2004, with yields in excess of 00 bu/a, yields increased with plant population, while in 2006, with much lower yield potential, yields were generally better with lower plant populations. Overall, yields similar to those of every-row planting could be obtained with skiprow planting in low-and high-yielding years; however, skip-row planting did not result in higher yields than everyrow planting in any year.

INTRODUCTION
Skip-row planting of dryland corn may offer producers a strategy for managing risk of drought. With limited water availability, corn during drought years may exhaust available soil water during vegetative growth, creating severe water stress during reproductive stages and grain fill. With skip row planting, soil water may be available later in the growing season in the skipped rows, because corn roots would require additional time to extend into these areas. This would reserve water for reproductive stages of growth. The objective of this study was to determine whether some pattern of skip row planting would improve drought tolerance of dryland corn.

MATERIALS AND METHODS
Research on skip row dryland corn was initiated at the K-State Southwest Research-Extension Center near Tribune in 2004. The planting arrangements were plant row and skip row, plant 2 rows and skip row, plant 2 rows and skip 2 rows, along with plant every row (30 inch rows). Target plant populations were 0,000, 5,000, and 20,000 plants/ a. Corn was no-till planted into standing wheat stubble in early May of 2004 to 2006. Roundup-Ready corn was used to facilitate late season weed control. The center of each plot was machine harvested after physiological maturity and yields adjusted to 5.5% moisture.

RESULTS AND DISCUSSION
Corn yields were above average in 2004 and 2005 with some treatment yields above 00 bu/a in 2004 (Table ) and above 90 bu/a in 2005 (Table 2). In both years, no treatment produced yields greater than corn planted every row at a population of 5,000 plants/a. However, the PS row arrangement produced similar yields. The other two planting arrangements (P2S and P2S2) tended to reduce yield potential. Plant population had more impact on yield that skip row planting. In 2004, with yields in excess of 00 bu/a, yields increased with plant population. With overall lower yields in 2005, a plant population of 5,000 plants/a produced the best yields.
In 2006, yields were much lower than in previous years with no yields above 50 bu/a (Table 3). With every row planting, the highest yields were obtained with a plant population of 5,000 plants/a while with skip row planting the highest yields were obtained with 0,000 plants/a. Averaged across plant populations, yields were similar for all row spacings.
In 2005 and 2006, increasing plant population tended to increase the percentage of barren plants. Averaged across planting arrangements in 2005, 25% of the plants were barren at the highest plant population compared to only 0% at the middle population. In 2006, with lower yields and more water stress, more than 60% of the plants were barren at the high population compared to less than 20% at the lowest population. Skip row planting had no effect on the percent of barren plants.

INTRODUCTION
Winter canola production has increased in the southern Great Plains states of Kansas, Oklahoma, and Texas in recent years. Close to 60,000 acres were seeded in the 2005-2006 growing season, with additional increases expected in 2006-2007. Winter canola is a broadleaf crop that was first introduced to the region as a rotational crop with winter wheat. Planting winter canola enables use of alternative herbicides for suppressing hard-to-control grassy weed species. It also disrupts disease cycles that often plague continuous wheat production systems.
Winter canola is well suited for the growing conditions of the southern plains and possesses a 20 to 30 percent yield advantage over spring canola. Spring types flower a month later and are harvested approximately two weeks later than winter types. Flowering during a hotter period of the growing season and reducing the grain fill period decreases the yield potential of spring types. Until heat-tolerant spring cultivars are developed, winter canola will be the primary oilseed rape crop grown in the region.
Winter canola establishes best in firm, well-drained, medium-textured soils. It is imperative that canola has appropriate seed-to-soil contact because of its small seed size and shallow planting depth. Obtaining a uniform seeding depth provides a challenge but can be accomplished with properly adjusted no-till seeding equipment. No-till cropping practices are well accepted and utilized across the semiarid Great Plains, allowing for the conservation of surface soil moisture and reducing the potential for soil erosion. A canola seedbed that is too fine or overworked will lose soil moisture rapidly and crusting normally occurs after a heavy rain. Overly coarse seedbeds result in poor seed placement, poor seed-to-soil contact, and soils dry out rapidly. These hindrances to establishment may be avoided with no-till seeding. In addition, fuel savings exist with no-till cropping systems.
As regional interest in renewable energy sources grows, demand for canola oil as a feedstock for biodiesel is outpacing our understanding and ability to establish the crop, especially under no-till cropping systems. Establishing winter canola is a more significant undertaking than establishing winter wheat, particularly in years when soil moisture is lacking at fall planting. Stand establishment impacts all other periods of the growing season; the most important being winter dormancy. Plants that fail to establish adequately in the fall will have limited time to attain the minimum amount of growth necessary to survive the winter in the southern Great Plains. Obtaining a quality stand provides the greatest opportunity for winter survival and is critical for harvesting a high yielding crop. The objective of this study is to identify varieties with good winter hardiness and best suited to the environmental conditions in southwest Kansas.

PURPOSE
The purpose of this project was to evaluate winter canola variety lines from the National Canola Variety Trial and the University of Idaho for fall stand, winter survival, bloom date, harvest maturity, height, lodging, shatter resistance, yield, and test weight.

PROCEDURES
Winter canola was planted September 2, 2006, at 8 lb/a in 9-inch row spacings in plots 8 feet wide by 30 feet long, replicated three times in a randomized complete block design. Two days after planting, the site was fully irrigated through flood irrigation.

RESULTS and DISCUSSION
Canola plants averaged 8 leaves per plant at the time of measuring fall stand establishment. Data on spring stand evaluation, including final yield, will be collected and reported in 2007. Wichita, which is currently one of the most commonly planted varieties in south-central Kansas, averaged a visual rating of 87.3% fall stand establishment and 90% winter survival. The variety lines from the University of Idaho averaged 80-84% stand fall stand establishment and 94-00% winter survival. Variety fall stand establishment ranged from 80-9% and averaged 85% across all varieties (Table ). Winter survival was from 6-00% and averaged 90%. Producers have reported having poor winter survival in southwestern Kansas; this experiment shows varieties vary in their winter hardiness in the region and that tests like this are important for identifying varieties best adapted to the region.
It is important to note that irrigation was provided after planting, which improved fall stand establishment. In a separate dryland study, winter canola failed to establish even after a second re-seeding attempt. Due to the small seed size of canola and the commonly dry surface soil layer during the fall in western Kansas, winter canola production might be restricted to full and limited irrigation production systems only.

BACKGROUND
The central Great Plains region is prone to low and variable precipitation patterns and early terminal crop growth due to low plant-available water. This semi-arid production region has relied on fallow periods to increase plant-available water and reduce production risk. In western Kansas, the primary dryland crop rotation was winter wheat-fallow (WF), but when producers switch to no-tillage systems, the cropping system can be intensified because of increased stored available water. Summer annual crops such as grain sorghum, corn, or sunflower have been successfully produced in rotation with winter wheat in a winter wheat-summer crop-fallow (WSF) rotation and often result in greater economic net returns than WF. Producers, however, have been slow to adopt WSF despite reduced economic risk compared to WF. Producing an annual forage crop in rotation with winter wheat might reduce economic risk comparable to WSF and have greater producer acceptance than WSF due to more flexibility in the cropping system.
Critical elements of Kansas cropping systems include increased costs and reduced availability of irrigation water, higher nitrogen fertilizer costs, and stagnant commodity prices. These factors have increased decision-making complexity for all crop production inputs (water, nutrients, and weed control) and presented challenges for designing sustainable cropping systems that minimize economic risk.
Integrating cover crops into the crop rotation has been promoted as a weed IPM tool capable of reducing weed population density while reducing nitrogen fertilizer requirements and increasing cropping system profitability and sustainability. Other semi-arid locations have shown that planting a cover crop in place of fallow in a WF rotation often does not reduce subsequent wheat yield and that soil nitrogen can be increased when a legume cover crop is planted. Cover crop harvest is flexible because it can be harvested as a forage or grain crop or left unharvested as a green manure crop, and harvest can be determined based on plant-available soil-water status and anticipated precipitation. Harvesting the cover crop as forage requires less soil moisture than growing a grain crop and can result in mois-ture savings for the following crop.
Many producers are interested in including a legume cover crop in their rotation as a way of increasing soil nitrogen and reducing fertilizer expense. This is often accomplished in organic systems by including a biennial or perennial legume such as yellow sweet clover or alfalfa. Although biennial and perennial forages can fix more nitrogen, they also generally require more water than annual legumes. This is particularly significant in the central Great Plains, where crop yields are often limited by water. Winter or spring annual legumes might provide a better trade-off between water use and nitrogen contribution.
Green manure cover crops can reduce herbicide and fertilizer expenses, but do not generate economic returns. Harvesting a cover crop as an annual forage might generate an economic return as well as reduce herbicide and fertilizer expense. Research is needed to identify appropriate crop rotations, environments, and crop species to successfully integrate annual forage crops in rotation with winter wheat.
Our goal is to integrate an annual forage crop into the fallow phase of our cropping systems directly after a winter wheat crop is harvested. Studies around the state and the central Great Plains have indicated that yellow sweet clover, hairy vetch, and winter peas demonstrate potential adaptation to the region. Previous research found that cover crop growth in the central Great Plains needs to be terminated by May to reduce adverse affects on the subsequent winter wheat yield. Planting a mixed species of canola or triticale with a legume as compared to planting a legume might result only in greater crop competition with weeds and increased forage biomass production, resulting in greater economic return.

a. determine the influence on weed population dynamics
At the initiation of the study, two quadrats of square meter will be geo-referenced within each sub-plot to measure the baseline weed community and changes over time. Weed species and density will be measured within each quadrat during the winter wheat phase of the rotation in the spring prior to herbicide application. Throughout the study, the naturally occurring weed community will be observed and documented within the established quadrats to document any changes in the weed community. Changes may not be observed initially, but are desired outcomes for a long-term rotation study.

b. determine crop water use efficiency (WUE) and fallow use efficiency (FUE) of several different crop rotations
Data on environmental conditions (air temperature, soil temperature, solar radiation, and precipitation) will be measured throughout the experiment. Volumetric water content will be determined using a calibrated soil neutron probe with measurements taken every 30 cm to a 3 m soil depth at the time of planting winter wheat and cover crops in the fall, the beginning of December to quantify fall water use, in the spring at the beginning of active plant growth, April , at time of harvesting forage cover crops on May , and at time of harvesting winter wheat and cover crops for grain. In addition, soil water will be measured at the beginning and ending of each fallow period.
All soil water measurements will be taken from the same area throughout the duration of the study. The decrease in volumetric water content plus precipitation received during the growing period will be converted to plant available water and used to calculate crop water use efficiency (WUE) for cover crop grain and forage production. Additionally, volumetric water content within the top 8 cm of soil depth will be measured at planting winter wheat using time-domain reflectance (TDR) to determine soil moisture status within the seed zone at planting. The efficiency of fallow in the different rotations will be evaluated by measuring the increase in plant available soil water compared to amount of precipitation received during the fallow period. The percent of precipitation stored in the soil profile during the fallow period will be used to calculate fallow use efficiency (FUE).

c. optimize the economic returns of the cropping system by integrating grain and forage production based on interactions among water and weed populations
Winter pea, winter wheat, and winter canola grain yield will be measured each year in every crop rotation. A subsample of the harvested grain will be evaluated for protein and test weight. Inorganic (plant-available) N (NH4+ and NO3-) will be measured from the top 6 cm at winter wheat planting by extraction with N KCl. The effect of cover crops on winter wheat yield and grain quality, soil nitrogen, and weed density will be used to derive economic crop enterprise budgets for each rotation, and the economic return of each rotation will be compared to the traditional WF rotation in western KS. A break-even economic analysis will evaluate each rotation under alternative forage and grain price scenarios. The value of including a forage crop in the rotation will be determined by measuring forage biomass and nutrient composition. Forage biomass will be calculated by harvesting three quadrats of 0.25 square meters per plot prior to harvesting the full plot area. Forage biomass wet and dry weight will be measured to determine the percentage of dry matter (DM) at harvest. Forage will be dried in a forced-air oven at 60°C for 48 hours and weighed. Harvested forage will be composited by plot and ground using a 2-mm screen, followed by a -mm screen. A sub-sample of the ground forage will be analyzed for forage nutrient composition. Nutrient components measured will include DM, crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), relative feed value (RFV), calculated total digestible nutrients (TDN), net energy for milk production (NE), net energy for gain (NEg), and net energy for maintenance (NEm). Crop enterprise budgets that include grain and forage cover crops in place of fallow in a WF rotation will be evaluated to determine the most profitable crop rotations. A breakeven economic analysis will evaluate each rotation under alternative forage and grain price scenarios.

a. field days highlighting the research plots as demonstrations of integrating cover crops into traditional crop rotations and increase adoption of weed IPM
Annual field tours will be provided to farmers, crop advisors, and other interested parties to provide first-hand exposure to the alternative cover crop rotations and their influence on typical KS cropping systems in a field setting. Annual field days already held in the spring dealing with wheat production attract a good portion of county extension agents from the surrounding counties, agronomy professionals, and influential farmers. These field days provide an excellent opportunity to discuss and demonstrate the impacts of the various cover crops on wheat production to a group of individuals with influence far beyond the land they may control. Ideas and input from these sessions can help adjust specific rotations or cover crop combinations as the research and demonstration plots are moved forward into succeeding cycles. The field days will provide opportunities to showcase and describe the various cropping systems, explain the underlying ecological principles, and facilitate opportunities for input and feedback.

PROCEDURES
A cropping systems study was initiated in 2006 at Garden City that includes 3 two-year, no-till, winter wheat-based crop rotations with both years of the rotation present each year.
The experimental design is a randomized complete block with four replications. Each block is split by crop phase with each phase of the crop rotation present every year. Rotational crop is randomized within crop phase. Each split-block (crop phase) is 60 m wide by 50 m long, and the rotational-crop plot is 4.6 m wide by 50 m long. No fertilizer is applied to the winter forage cover crops and 80 kg/ha N is applied to winter canola and winter wheat during year of the rotation. Winter cover crops will be seeded the end of August and winter wheat will be seeded in mid-September. Crops grown for forage will be terminated May with an application of glyphosate plus 2,4-D prior to harvest to stop water uptake and control any weeds present. Seeding rates and methods for grain and cover crops will follow local recommendations.

RESULTS AND DISCUSSION
Current research in western Kansas indicates that winter pea might have greater stand establishment than yellow sweet clover, hairy vetch, or winter canola. The greater stand establishment of winter peas is due to a large seed size and placing the seed deeper in the soil profile into wetter soil. Soils in western Kansas are commonly dry in the fall and seeding deeper allows for improved stand establishment. If winter pea can be successfully grown in the dryland regions of western Kansas, it might provide a key annual legume growth cycle that optimizes water use efficiency while reducing the amount of nitrogen fertilizer required and the weed density during the subsequent winter wheat crop.

No. Year
Year 2 Winter pea (harvested as grain) Winter wheat 2 Winter pea (harvested as forage) Winter wheat 3 Yellow sweet clover (

SUMMARY
Research on four-year crop rotations with wheat and grain sorghum was initiated at the K-State Southwest Research-Extension Center near Tribune in 996. The rotations were wheat-wheat-sorghum-fallow (WWSF) and wheat-sorghum-sorghum-fallow (WSSF), along with continuous wheat (WW). Soil water at wheat planting averages about 9 inches following sorghum, which is about 3 inches more than the second wheat crop in a WWSF rotation. Soil water at sorghum planting is approximately .5 inches less for the second sorghum crop compared to sorghum following wheat. Fallow efficiency prior to wheat was greater for the shorter fallow period following wheat than for the longer fallow following sorghum. Prior to sorghum, average fallow efficiency was 38-40% and not affected by the previous crop. Grain yield of continuous wheat averages about 75% of the yield of wheat grown in a four-year rotation following sorghum. Except for one year, there has been no difference in yield of continuous wheat and recrop wheat grown in a WWSF rotation. Yields are similar for wheat following one or two sorghum crops. Similarly, average sorghum yields were the same when following one or two wheat crops. Yield of the second sorghum crop in a WSSF rotation averages about 70% of the yield of the first sorghum crop.

INTRODUCTION
In recent years, cropping intensity has increased in dryland systems in western Kansas. The traditional wheat-fallow system is being replaced by wheat-summer crop-fallow rotations. With concurrent increases in no-tillage, the question arises as to whether more intensive cropping is feasible. The objectives of this research were to quantify soil water storage, crop water use, crop productivity, and profitability of four-year and continuous cropping systems.

MATERIALS AND METHODS
Research on four-year crop rotations with wheat and grain sorghum was initiated at the K-State Southwest Re-search-Extension Center near Tribune in 996. The rotations were wheat-wheat-sorghum-fallow and wheat-sorghum-sorghum-fallow, along with a continuous wheat rotation. No-till was used for all rotations. Available water was measure in the soil profile (0 to 8 ft) at planting and harvest of each crop. The center of each plot was machine harvested after physiological maturity and yields adjusted to 2.5% moisture.

RESULTS AND DISCUSSION
Soil water: The amount of available water in the soil profile (0 to 8 ft) at wheat planting varied greatly from year to year ( Fig. ). Soil water was similar following fallow after either one or two sorghum crops and averaged, across the 0-year period, (about 9 inches). Water at wheat planting of the second wheat crop in a WWSF rotation was always less than the first wheat crop except in 2003, which had the lowest water content at planting of any year. Soil water for the second wheat crop averaged more than 3 inches (or about 35%) less than the first wheat crop in the rotation. Continuous wheat averaged about inch less water at planting than the second wheat crop in a WWSF rotation. Fallow efficiency (amount of water accumulated from previous harvest to planting of current crop divided by precipitation during fallow) ranged from less than 0 to more than 60%. Fallow efficiency was greater for the shorter (3 month) fallow period following wheat than for the longer ( month) fallow following sorghum. Following sorghum, fallow efficiency prior to wheat averaged less than 30% compared to more than 40% for wheat following wheat.
Similar to wheat, the amount of available water in the soil profile at sorghum planting varied greatly from year to year (Fig. 2). Soil water was similar following fallow after either one or two wheat crops and averaged ( years) about 8.6 inches. Water at planting of the second sorghum crop in a WSSF rotation was always less than the first sorghum crop although sometimes by very little. For instance, in 998, there was less than 0.25 inch difference between them. When averaged across the entire study period, the first sorghum crop had about 1.5 inches more available water at planting than did the second crop. Similar to wheat, fallow efficiency prior to sorghum ranged from less than 0 to more than 60%. In contrast, to wheat, average fallow efficiency prior to sorghum was similar following wheat or sorghum at 38 to 40%.
Grain yields: Wheat yields were below the long-term average in 2006 (Table ). Averaged across 0 years, recrop wheat (the second wheat crop in a WWSF rotation) yielded about 86% of the yield of first-year wheat in either WWSF or WSSF rotations. Before 2003, recrop wheat yielded about 70% of the yield of first-year wheat. In 2003, however, the recrop wheat yields were more than double the yield in all other rotations. This is possibly due to the failure of the first-year wheat in 2002, resulting in a period from 2000 sorghum harvest to 2003 wheat planting without a harvestable crop. There has been no difference in wheat yields following one or two sorghum crops. The continuous-wheat yields have been similar to recrop wheat yields, except in 2003.
Sorghum yields in 2006 were more varied than the long- term yield average (Table 2). Sorghum yield following wheat was about the same or somewhat less than the longterm average while sorghum following sorghum was much less than the long-term average. The second sorghum crop yield averages about 70% of the yield of the first sorghum crop; however, in 2006, second year sorghum yields were less than 25% of the first-year sorghum yield. Averaged across years, sorghum yields were the same following one or two wheat crops.

SUMMARY
Research was initiated under sprinkler irrigation to evaluate limited irrigation in a no-till crop rotation. With limited irrigation (0 inches annually), continuous corn was more profitable in 2006 than multi-crop rotations, including wheat, sorghum, and soybean. Averaged across the past four years, continuous corn has been the most profitable system primarily because of spring freeze and hail damage to the wheat in the multi-crop rotations. In multi-crop rotations, relatively poor results with one crop (in this case wheat) can reduce profitability compared to a monoculture, especially when the monoculture crop does well. However, the multicrop rotation may reduce economic risk when the monoculture crop does not perform so well. All of the multi-crop rotations had net returns of only $20 per acre less than continuous corn, so only relatively small changes in prices or yields would be needed for any of the rotations to be more profitable than continuous corn, indicating the potential for alternate crop rotations under limited irrigation.

PROCEDURES
Research was initiated under sprinkler irrigation at the Tribune Unit of the Southwest Research-Extension Center in the spring of 200. The objectives are to determine the impact of limited irrigation on crop yield, water use, and profitability in several crop rotations. All crops are grown no-till; other cultural practices (hybrid selection, fertility practices, weed control, etc.) are selected to optimize production. All phases of each rotation are present each year and are replicated four times. All rotations have annual cropping (no fallow years). Irrigations are scheduled to supply water at the most critical stress periods for the specific crops and are limited to .5 inches per week. Soil water is measured at planting, during the growing season, and at harvest in one-foot increments to a depth of 8 feet. Grain yields are determined by machine harvest. An economic analysis determines optimal crop rotations. The rotations include one-, two-, three-, and four-year rotations. The crop rotations are ) continuous corn, 2) corn-winter wheat, 3) corn-wheatgrain sorghum, and 4) corn-wheat-grain sorghum-soybean (a total of 0 treatments). All rotations are limited to 0 inches of irrigation water annually, but the amount of irrigation water applied to each crop within a rotation varies depending upon expected responsiveness to irrigation. For example, continuous corn receives the same amount of irrigation each year, but more water is applied to corn than to wheat in the corn-wheat rotation. The irrigation amounts are 5 inches to corn in two-, three-, and four-year rotations, 0 inches to grain sorghum and soybean, and 5 inches to wheat.

RESULTS AND DISCUSSION
The wheat in all rotations followed corn and received 5 inches of irrigation. All rotations were limited to 0 inches of irrigation, however the corn following wheat received 5" since the wheat only received 5 inches. This extra 5 inches of irrigation increased corn yields about 50 bu/a compared to the continuous corn (which only received 0 inches of irrigation) (Table ). Corn yields tended to be greater with the longer rotations. Grain sorghum yields were the same in the three-and four-year rotations.
Averaged across the past four years, corn yields were 42 to 47 bu/a greater in the multi-year rotations with an additional 5 inches of irrigation compared to continuous corn (Table 2). Wheat and grain sorghum yields were similar regardless of length of rotation.
An economic analysis (based on October grain prices and input costs from each year) found that the most profitable rotation was continuous corn ( Table 3). All of the multiyear rotations had similar net returns of about $20/acre less than continuous corn. The reason for the lower returns in the rotations was the low returns from wheat. In two of the past four years, wheat yields were depressed by spring freeze damage, which lowered the average wheat yields reducing the net returns from the multi-year rotations.

SUMMARY
Research was initiated under sprinkler irrigation to evaluate limited irrigation with no-till for four summer crops. In 2006, crop yields were generally greater than the longterm average yields. Corn responded the most to increased irrigation. Because of changes in growing conditions, the most profitable crop may be a different one from year to year. Growing different crops when irrigation is limited can reduce risk and increase profitability. Averaged across the past six years, corn has been the most profitable crop at higher irrigation amounts, while grain sorghum and soybean have been the more profitable crops at the lowest irrigation amount.

PROCEDURES
A study was initiated under sprinkler irrigation at the Tribune Unit of the Southwest Research-Extension Center in the spring of 200. The objectives are to determine the impact of limited irrigation on crop yield, water use, and profitability. All crops are grown no-till and other cultural practices (hybrid selection, fertility practices, weed control, etc.) are selected to optimize production. All water levels are present each year and replicated four times. Irrigations are scheduled to supply water at the most critical stress periods for the specific crops and limited to 1.5 inches per week. Soil water is measured at planting, during the growing season, and at harvest in one-foot increments to a depth of 8 feet. Grain yields are determined by machine harvest. An economic analysis determines optimal water allocations. Irrigation amounts are 5, 0, and 5 inches annually. The crops evaluated are corn, grain sorghum, soybean, and sunflower grown in a four-year rotation (a total of 12 treatments). The crop rotation is corn-sunflower-grain sorghum-soybean (alternating grass and broadleaf crops). The irrigation amounts for a particular plot remain constant throughout the study; e.g., a plot receiving 5 inches of water one year when corn is grown will also receive 5 inches in the other years when grain sorghum, sunflower, or soybean are grown.

RESULTS AND DISCUSSION
Precipitation from June through August 2006 was 4.45 inches (57% of normal). Corn responded most to irrigation, with yields of 67 bu/a greater when receiving 0 inches rather than 5 inches of irrigation. It yielded 78 bu/a more with an additional 5 inches of irrigation (Table ). Sorghum yields were improved least by increased irrigation. In 2006, the original plots in the limited irrigation study were split, as they were in 2005, and a seeding rate approximately 20% higher was added to each crop except corn, where the seeding rate was reduced by 20%. The original seeding rates were 30,000 for corn, 80,000 for sorghum, 50,000 for soybean, and 23,500 for sunflower. The same hybrids were used for each crop except for sorghum, where a longer-season hybrid was planted at the higher population. For corn, the lower seeding rate increased corn yields at the lower irrigation amounts and slightly decreased yields at the high-  223 (2) 23 (65) 49 (48) 360 (300) The values in parentheses are for about 20% different seeding rate.
est irrigation amount. The increased seeding rate had little effect on soybean and sunflower. Sorghum yields were greater with the higher seeding rate at the higher irrigation amounts, but since this also involved a different hybrid, it is not possible to determine which factor affected yield. Averaged across 200-2006, corn was the most responsive to higher irrigation amounts (Table 2). Corn yields increased 8% when irrigation was increased from 5 inches up to 5 inches while grain sorghum increased 34%, soybean by 48%, and sunflower by 21%.
An economic analysis (based on original seeding rates, October grain prices each year, and input costs from each year) found that, at the lowest irrigation level, average net returns  were similar for soybean and sorghum (Table 3) followed by corn. At the higher irrigation levels,

SUMMARY
Total soil water management during the growing and non-growing season can be enhanced with crop residue management. Capture and retention of soil water plus supplemental irrigation at critical growth stages can maximize limited irrigation resources. This research quantifies the water use and irrigation requirements of corn, winter wheat, grain sorghum and sunflower crops grown with optimum water management using all water conservation techniques available. Differences in grain yields between conventionally tilled and no-till management tended to increase as irrigation decreased. Crops in no-till practices utilized water better unless both systems were fully irrigated. The outcome is the potential reduction of irrigation requirements for more fully irrigated crops and increased grain yields for limited-irrigation crops.

INTRODUCTION
Past irrigation management research has demonstrated that annual grain crops respond best to water applications during flowering and seed-fill growth periods. No-till management systems, which leave crop residues on the surface, have been beneficial in reducing soil water evaporation in sprinkler irrigation. At the same time, there are pressures from the livestock industry to use these same crop residues for livestock forages. This project is designed to combine the best irrigation and crop residue management techniques into one management system. The products of this project are relationships between grain yield and water use, as well as grain yield and irrigation. By harvesting the plots for both grain and forage, the value of crop residues either for water conservation or livestock rations can be estimated. The objectives of this study were: () to measure the grain yield-irrigation and grain yield-water use relationships for corn, grain sorghum, winter wheat, and sunflower crops in no-till management with irrigation inputs from 3 inches to full irrigation, and (2) to compare the relationships between whole plant forage yield, quality, and estimated feed value for limited and fully irrigated corn and grain sorghum in a livestock system to the value of the same material as surface residue for water conservation and soil water evaporation suppression in a total grain production system.

PROCEDURES
The experimental field (18 ac) was subdivided into six cropped strips that were irrigated by a four-span linear move sprinkler irrigation system. The cropping sequence was corn-corn-soybean-winter wheat-sunflower-grain sorghum. The soil was a silt loam with pH 8.3 and a slope of less than %. Irrigation amounts varied in this experiment. The six irrigation treatments, replicated four times, received from 3 to 5 inches of water during the growing season, if needed. If rainfall was sufficient to fill the soil profile to field capacity, irrigation was not applied. The extra irrigation allocation was rolled over to the next growth stage. If there was extra allocation at the end of the year, it was not carried over to the next year.
Soil water was measured once every two weeks with the neutron attenuation method in increments of 2 inches to a depth of 8 feet. There was one sampling site per plot. These measurements were used to calculate crop evapotranspiration (ETc) for each two-week period during the season.

RESULTS AND DISCUSSION
This study was based on no-till crop and irrigation management from soil water data. Each crop responded differently to irrigation (figure 1). Average crop yield responses from irrigation for 2004, 2004, and 2005 were compared with yields from conventional till practices. The yield-irrigation relationships for conventional tillage management were derived from 20 years of field plot research in western Kansas. These three years provided a range of growing conditions. In 2004, weather provided desirable crop growing conditions which produced above-average yields of 230 bu ac-for corn. An early July hail storm in 2005 reduced corn's peak leaf area index (LAI) by 33% from 2004. The result was maximum corn yields of 65 bu ac-in 2005. Although less hail damage was measured in from a storm in mid-July 2006, corn's peak LAI was reduced by 4% from 2004. The maximum 2006 corn yield was 85 bu ac-.
Corn yields increased the most with added irrigation, but no-till sorghum, wheat, and sunflower had little response to irrigation. Conventional tillage research indicated that all crops would increase yields with added water, but by different amounts. Generally, conventional and no-till management had the same yields when irrigation did not limit production. No-till management provided more yields for the same irrigation when water was limited.
The common result among all crops is the tendency for no-till management to produce more grain from the same water applied than conventional management. This result could be produced by several factors. Crop residue coverage on the soil surface could positively impact precipitation capture (runoff control and enhanced infiltration) and storage in the root zone. The same residue could reduce soil water evaporation from the root zone. The results clearly reinforce the long-known ability of corn to increase production per unit of water applied more than other common annual crops do.
Crop residues provide surface coverage that has positive benefits for water conservation, as this study's results indicate. However, competing pressures for other uses of stubbles and forages are becoming more common. They can provide livestock roughages and cellulose for fuel generation. For example, the dairy industry can compete for alternative use of crop residues. Forage samples from the study's plots were harvested and analyzed for quality factors important in dairy rations (table ). Potential mild production from corn and sorghum forage was estimated utilizing the Milk2000 program, which converted forage quality factors into milk production. The program predicted that corn forage would produce more milk than would grain sorghum forage. Decreasing amounts of irrigation caused reduced forage yields, which led to less milk production. This result could be correlated with less biomass produced with less applied water.
Forage quality did not change greatly with increasing amounts of irrigation. It appears from these data that dry matter yield was more important than changes in forage quality. Increasing irrigation on corn increased estimated milk revenue by 38%; however, increasing irrigation on grain sorghum only increased estimated milk revenue by 7%. These data indicate that corn was more responsive to irrigation than grain sorghum in terms of dry matter produced. Corn also had better forage quality as measured by TDN than did grain sorghum over all irrigation treatments.
Systems management, including crop residues and irrigation timing, for limited water resources has the potential for reducing water applications and/or increasing crop yields. Competition for uses of crop forages will need careful scrutiny with respect to impacts on water resources. These forage harvest results will help understand the tradeoffs between using forage for livestock feed or for water conservation.

SUMMARY
Soil water evaporation was measured beneath sprinkler irrigated no-till corn and soybean crops with mini-lysimeters. The frequency and wetting patterns of sprinkler irrigation keep the soil surface vulnerable to evaporation controlled by radiant and convective energy. This study documented the role of irrigation frequency and crop residues on the soil surface in reducing this evaporation. Soil water evaporation from bare soils can be reduced by half with nearly 00% surface coverage of crop residues during the growing season in sprinkler irrigation management. Reducing soil water evaporation with adoption of crop residue management techniques can lead to reduced pumping and energy costs for irrigators with adequate water and increased crop production for irrigators with limited water supplies.

INTRODUCTION
High-frequency sprinkler irrigation leads to a preponderance of energy-limited evaporation during the growing season. Crop residues left in place on the surface can have an impact on reducing evaporation. Shifts in tillage systems may influence evaporation (E) and transpiration (T) partitioning so that yield-ET (evapotranspiration) relationships evolve and threshold ET values change. A better understanding of the energy balance components of crop canopies, surface residue, and soil surface is needed. The objectives of the study were: . To measure soil water evaporation in a corn canopy with wheat stubble or corn stover surface cover simulating no-till residue management. 2. To find the fraction of ET credited to E for three soil surface conditions. 3. To measure E from partially covered soil surfaces.

PROCEDURES
A field study was conducted in Garden City during [2003][2004][2005][2006] to test the effectiveness of corn stover and wheat stubble for evaporation suppression in soybean and corn grown in 30-inch rows. Two 2 inch diameter PVC cylinders that held 6 inches deep soil cores were placed between adja-cent soybean or corn rows. These "mini-lysimeters" were pressed into undisturbed soil. The soil was bare or covered with no-till corn stover or standing wheat stubble to test the maximum effectiveness of various residues for evaporation suppression. Crop and mini-lysimeter treatments were replicated four times. Mini-lysimeters were irrigated once or twice weekly when rainfall did not satisfy crop needs. The mini-lysimeters were weighed daily, and the weight differences were translated into the evaporation amounts. Corn plant populations in the surrounding plot area were reduced to match irrigation management in the once per week frequency treatment.
A second set of replicated mini-lysimeters was established in a controlled outdoor, non-cropped setting. Irrigated mowed grass surrounded the control area. The minilysimeters were buried in the ground until flush with the surface. The 2 experimental treatments included six possible surface cover treatments (bare soil; 25%, 50%, 75%, or 00% coverage with corn stover; or 89% coverage with wheat stubble) with one of two irrigation frequency treatments (once per week or twice per week). Partial-cover corn stover treatments were established by evaluating the residue application with line-transect methods using mesh grids over the mini-lysimeters. The 00% corn stover and wheat stubble treatment lysimeters were similar to the field plot study treatments. The partial cover treatments were intended to simulate tillage practices equivalent to one-pass chisel, one-pass tandem disc, and two-pass tandem disc for approximately 75%, 50%, and 25% of corn stover cover remaining, respectively.

RESULTS AND DISCUSSION
Data in figure 1 are averaged over irrigation frequency (full or limited irrigation) and lysimeter placement position (to the east or west of the centerline between two adjacent crop rows). Crop evapotranspiration (ETc) was the same across surface cover treatments, when considering the average irrigation results. Average daily evaporation (E) was significantly different among the three surface treatments. Corn stover surface cover and dry matter were somewhat more than wheat stubble (see below), which contributed to more E from the wheat stubble mulch. Variations in E were similar to variations in E/ETc because ETc was constant when averaged over surface treatments.
Average E decreased as the crop grew and matured (figure 2). ETc increased from the vegetative to reproductive growth stages. Then ETc decreased during grain fill. These trends are typical for corn.
The mass of corn residue remaining on the mini-lysimeters at the end of the no-canopy study was 0.68, 2.9, 2.0, and . tons/ac for respective surface cover values of 25%, 55%, 75%, and 00%. One wheat stubble treatment was covered with 8.9 tons/ac which corresponded to 89% coverage. Average daily E data were correlated with surface coverage (SC) by crop residue or dry matter (DM) of the crop residue (figure 3). Average daily E remained fairly constant over the range of 0 to 60% surface cover. From 60 to 00% coverage, average daily E decreased until the E rate for complete surface cover was half that of the no-cover treatment. Daily E rates decreased steadily with increasing dry matter. The maximum crop residue dry matter also yielded half of the daily E rate compared with bare soil.
No matter how efficient sprinkler irrigation applications become, the soil is left wet and subject to evaporation. Frequent irrigation and shading by the crop leave the soil surface in the state of energy limited evaporation for a large part of the growing season. This research found that evaporation from the soil surface (E) is a substantial portion of total ET. As much as 30% of ET was E for bare soil conditions during the irrigation season under corn and soybean canopies with silt loam soils. Under a variety of climatic conditions, crop residues reduced the evaporation from soil in half even beneath an irrigated crop canopy.

SUMMARY
Reducing income risk is often an irrigator's motivation for switching crops as water availability declines. The Crop Water Allocator (CWA), in its present form, ranks alternative planting patterns based on mean income alone, without considering outcomes associated with changes in input variables. This risk arises from a variety of factors that are uncertain at the time of planting; the most important of these is weather conditions during the growing season. For example, although corn often generates the highest mean income, it is also likely to have a highly uncertain yield because its growth is very sensitive to water stress during critical stages of the growing season. Adding trend analysis to CWA can project net returns over a range of input variables. Wet, dry, and median rainfall years can be simultaneously examined to find trends in net returns. The same methods can be used to project income trends from commodity prices, maximum yields, production costs, irrigation costs, and irrigation efficiency. Trend processing capabilities were added to the CWA. Ranges of user input variables can be entered with ranges of net economic returns as the output. These results indicate the income risks when rainfall, irrigation costs, crop production costs, irrigation efficiencies, commodity prices, or crop maximum yields vary. The CWA is available to download to an individual's computer from the following world wide web site: oznet.ksu.edu/mil.

INTRODUCTION
Income risk analysis has been added as a feature in existing CWA software. This option allows users to account for net-income shifts in response to trends in program inputs that vary from year to year. These input variables are: rainfall, irrigation efficiency, commodity prices, maximum crop yields, irrigation costs, and crop production costs. The trends of net-income or net-return are the basis for user decisions about the most appropriate cropping system.
Trend analysis allows the user to find net returns over a range of possible inputs: rainfall, irrigation efficiency, commodity prices, maximum crop yields, irrigation costs, and crop production costs. Fixed trend and variable trend processing are available. Fixed trend analysis starts with the user's execution of CWA and selection of one resulting cropping system. Two input ranges can be simultaneously processed in fixed trend analysis to find the influence of both inputs on net return. The results from fixed trend analysis are the changes in net return from a range of one or two inputs for a selected cropping system. The variable trend analysis is derived from the range of one of the possible inputs. The CWA is not executed in the normal fashion by the user. Crop choices, irrigation allocations and land allocations vary as part of the analysis. The outcome from variable trend analysis is the response of cropping patterns, land allocations, and water allocations to the range of the input. Variable trend analysis may be used by policy makers to forecast shifts in regional cropping systems from changes in an input variable The original CWA has been preserved. If a user wants to ignore trend analysis, the choice can be made at the initial program screen. Output from trend processing is captured in EXCEL spreadsheets. This feature gives the user the ability to process output into table or graphical formats.

RESULTS AND DISCUSSION
Trend processing is an extension of CWA that permits entry of a range of values or the variables commodity price, maximum yield, production costs, irrigation system efficiency, and irrigation costs. For example, the program user may be interested in the response of net returns if irrigation costs vary from $5 to $5 per acre-inch. CWA executes a series of calculations over the range of irrigation costs, producing the corresponding range of net returns. Trend processing should be attempted only after the user becomes familiar with execution of CWA for one scenario at a time. Trend processing is initiated as an added feature of CWA with the "Trend Processing Start" on the entry page. Trend processing can be discontinued or enabled with the "Tools" option on the main input page.
Fixed trend processing is one of two option of trend processing, available after CWA normally executes the user's scenario. All basic inputs for the scenario must be entered (land area, irrigation costs, land split, irrigation efficiency, available water, rainfall, and production costs, prices, and maximum yields for each crop selected). The "generate output" key will initiate calculations of net returns for over all possible combinations of land and irrigation allocations. The user must select one of the options for fixed trend processing. The fixed trend feature processes only the one selected option. Activating the "Run Fixed Trend" on the selected option" will take the user to a page for the input variable range selection. For example, the range of commodity prices will lead to a corresponding range of net returns. An added option for fixed trend processing is the ability for CWA to consider two input ranges simultaneously. "Add a trend variable" switches the input entries to the second variable. For example, ranges of a commodity price and irrigation costs may be considered and results are presented in a two-way table of net returns in EXCEL. Users can further represent these results in three dimensional graphs (figure 1).
Variable trend processing is the second option for trend processing in CWA. In variable trend processing, crop selections, water allocation, and land applications can change to find optimum solutions for each value in the range of input specified. All input values must be entered before executing variable processing (land area, irrigation costs, land split, irrigation efficiency, irrigation amount, rainfall, production costs, prices, and maximum yields for each crop selected). However, the "generate output" button is not used to ini-tiate variable trend procession. Variable trend processing is initiated from the TOOLS option on the main input page only after all input values have been entered. The range of the chosen input variable is entered before execution. Only one input variable can be examined with variable processing. Execution of the variable processing will precede any normal execution of CWA results. The limitation of variable trend processing is that options one to four of each solution will be examined and reported in the EXCEL output. Applications of variable trend solutions are predictions of trends in crop selections and land and water allocations over a range of an input variable. For example, if annual precipitation varied from to 2inches, how would cropping patterns change (Table )?
The trend analysis feature of CWA opens the door for users to examine the risks in net returns when input values vary over a specified range. Volatile commodity prices, escalating production and irrigation costs, uncertain rainfall and possible water allocations cause producers and policy makers to project micro and macro economic effects. CWA has been a model that predicts crop selections, land allocations, and water allocation from one set of inputs. The trend analysis extends CWA's capability for results from a range of inputs.

SUMMARY
KanSched2, an ET-based irrigation scheduling program, was developed and released for public distribution for use by farmers, crop consultants, researchers, government agency personnel, and others in the Ogallala Aquifer region. Evapotranspiration (ET)-based irrigation scheduling can help conserve water and energy resources. KanSched-2 has many new features and options, including an expansion of pre-programmed summer crops, an alfalfa/summer forage crop module, a fuel use and cost module, a crop water use forecast tool, improved data input/output options, and a storage module for well and water meter records. Kan-Sched2 retains the layout and control button format of the original version, allowing KanSched users to make an easy transition to KanSched2 use. New users will find that KanSched2 to be user-friendly.

INTRODUCTION
As farmers and crop consultants face rising fuel costs and limited water supplies, sound irrigation water management decisions are needed. With current computer technology and readily available weather data, computer-based irrigation scheduling models can be used by almost anyone. However, the model needs to be user-friendly and must meet consumer needs. While computer-based irrigation scheduling models have been in existence for some years, most were not adopted and used because they required extensive training and/or were difficult to use. The KanSched model was designed to be very user friendly and easily adopted through minimal training. The success of that model has been demonstrated through the Kansas Mobile Irrigation Lab (MIL) water conservation project (www.oznet.ksu. edu/mil/). However, the original KanSched model was developed for irrigated corn in southwestern and south-central Kansas. While successful patches have been developed to include other crops and soil conditions, it became necessary to redesign and code the original model to meet the needs of a larger customer base and to include other cropping systems common to the entire High Plains region. The objective was to redesign and rewrite the KanSched irrigation scheduling program for use with common High Plains irrigated crop production systems.

PROCEDURES
The general functionality of the new KanSched2 program is similar to the general format of the existing KanSched program. KanSched2 has been built in an object-oriented programming language using Microsoft's Visual Basic. During 2005, KanSched2 was designed and developed using the following elements in addition to the functions of the existing KanSched program: . additional summer crop modules include corn, cotton, dry beans, sorghum, soybean, and sunflower; 2. wheat (winter and spring) crop modules and an alfalfa/ summer forage crop module; 3. an initial soil profile moisture content that is now userdefined; 4. a data input/output structure was incorporated to use and store data in an ASCII comma-delimited mode; 5. a crop water-use forecast tool (this tool uses current ET data and a crop coefficient curve to predict future crop water requirements for the next 5 days, and it also uses current soil water storage to estimate the next irrigation date); and 6. a fuel cost input page (similar to FuelCost Online, www. oznet.ksu.edu/mil/) that can be used to track and display fuel use and cost on each system (required user inputs will include: system capacity [gpm], depth to pumping water level in feet, wellhead operating pressure in psi, pumping plant energy type [diesel, natural gas, electricity, propane] and unit cost of fuel, as well as the option to input actual energy costs to estimate future costs). KanSched2 allows for easier sharing of field information. Fields can be grouped together into field collections. Individuals using KanSched2 will most likely have only one field collection that would contain all irrigated fields being scheduled. Agency personnel and crop consultants would likely make a collection for each producer client.

Supported in part by
KanSched2 also allows import of ET and rainfall data in the formats noted in Figure . Data from the daily budget page can also be exported (as noted in item 4 on previous page).
Activation of the "Field Setup" control button results in five input pages being revealed to the user. The general information page, shown in Figure 2, allows input of the crop type. The selection of crop type automatically triggers the proper selection of crop coefficient information. Eighteen crop options are pre-programmed into KanSched2. A new feature that can be utilized on this page is the ability to customize existing crop coefficients or add new crops to the selection list. This makes KanSched2 more versatile and adaptable to other climatic regions.
The initial soil water content at the start of the water budget date is easily entered on the "Soil and Roots" page during field setup shown in Figure 3. Notice also that asso-ciated with most input boxes is text that describes the input needed, making on-screen help instantly available, but with minimal or no distraction for the user.
"Forecast" is a new feature of KanSched2 shown in Figure 4. The estimated ET demand can be adjusted by using the sliding marker on the ET demand bar. Predicted crop ET and the associated soil water level for the prediction period are shown in the text at the lower section of the page. "Irrigation System," shown in Figure 5, is also a new feature of KanSched2. If activated, the cost of application for each irrigation will be tracked and displayed on the budget page (not shown).
KanSched2 also has a feature, called "Water Information," that allows a producer to store well and water meter information for a field. This feature may be useful to any user of KanSched2, but could be particularly useful to Kansas producers when preparing irrigation water use reports required by the State of Kansas.

CONCLUSION
KanSched 2's official release was publicized via radio interviews and news releases, as well as e-mail notices to county extension agents and Kansas NRCS personnel. Kan-Sched2 also has been submitted for approval by the NRCS computer software review committee. Survey information gathered after multiple hands-on training sessions with various groups indicate that KanSched2 and the training format is being well received. The quality assessment by participants ranked the quality and organization of presentation very close to excellent (4.22 on a scale of 5). The depth of the material was ranked in the median (3.37, where was "too difficult" and 5 "too easy"). For usefulness or applicability of KanSched2, the ranking was again close to excellent (4.22 on a scale of 5).

K STATE INTRODUCTION
Drip irrigation has proven to be an effective irrigation method for saving water and improving returns for highdollar cash crops. However, surface drip systems are not as suitable to the field cropping system practiced in the Central Great Plains. Kansas State University's research on suitability of using subsurface drip irrigation (SDI) has shown that it is a feasible technology for irrigating field crops like corn. More than 2 million acres out of 3 million irrigated in Kansas depend on groundwater from the Ogallala Aquifer. Producers are experiencing water-level declines and rising pumping costs because of greater depth of pumping and increasing fuel costs. Economic comparison of systems indicates that a well managed SDI system with a promise of fifteen or more years of life is economically competitive, although it requires a high investment initially. Extension demonstrations have encouraged a steady increase in acreage irrigated by SDI; initially, many of these systems were installed in small farms with limited water where a part of the water supply was diverted from existing flood or center pivot sprinkler irrigation systems. Lately, producers with large acreage under flood irrigation have started switching to SDI. Statewide SDI acreage is estimated at 20,000 acres, most of which is in western Kansas and represents about % of irrigated crop land. Although no major concern regarding system failure has surfaced, the present operational condition of these systems was evaluated to provide fieldperformance information to farmers intending to adopt SDI. The study objective was to assess the operational condition of the existing SDI systems and the level of producer satisfaction. Information could help address clientele needs and keep service providers informed.

PROCEDURES
A questionnaire was sent out to 297 producers. The sample questionnaire may be viewed at http:www.oznet.ksu. edu/SWAO/Irrigation/sdi.htm under the link"Field Performance of SDI." The mailing list of producers was prepared from sign-up lists of farmers attending extension educational meetings on SDI and a list obtained from the Kansas State Division of Water Resources of producers reporting use of microirrigation. Recipients of survey forms were asked to return the survey form even if they were not SDI users. The survey requested information regarding acreage, installation, and performance satisfaction.

RESULTS AND DISCUSSION
Results indicated that producers were generally satisfied with their SDI systems. The majority of SDI systems were installed by the joint efforts of producers and contractors (54%). Contractor-installed systems account for 9% and the remainder (27%) were self-installed by the producers.
When asked if the producers had received an "as-built" drawing or diagram of the system from the contractors, 34 positive responses were received and 4 were negative. The response on receiving operational and maintenance instructions or operating procedures for the SDI system was similar; 33 received instructions and 5 did not receive instructions on operational procedures.
The survey asked about the level of satisfaction with the SDI system, using a level of satisfaction scale of ("very satisfied") to 5 ("unsatisfied"). The majority rated their level of satisfaction as "very satisfied" (17) or "satisfied" (19); other response options were "almost satisfied" (4), "somewhat satisfied" (4), and "unsatisfied" (2).
Most respondents (30) planned to expand acreage under SDI; however, 9 indicated they did not plan to expand their SDI acreage at that time.
The survey asked producers to list their own concerns regarding the SDI systems. The major concerns were: • Rodent, gopher, and other vermin damage requiring many hours of repair; this was the most-cited concern (37 responses). • Filtration is a concern, but with a good system and maintenance there was no problem. Some asked if there were better filtration systems available or should one oversize to avoid frequent cleaning. (5) • Clogging due to iron bacteria and calcium precipitation is a concern. Some reported clogging from pumpoil drips. Clogging from drip oil is more evident in pumps with low capacity or fluctuating water levels. Finally, the survey asked producers to list information needs that Kansas State Research and Extension might be able to address. The responses from the producers were as follows: • Rodent control -how and what to use. • Fertilizer use through SDI, including micronutrients. • More educational meetings, seminars on management (both pre and post season). Arrange field tour to visit systems and exchange information with other operators.
• Drip tape spacing for crops other than corn. More research for alternative crops under SDI.
• More information about planting alfalfa under SDI. • How to germinate seed in dry soil or conserving moisture in surface soil for planting. • How to unclog drip lines. How one may keep systems clean with different water supplies.
• System capacity, how much water to use, and limited water issues. • Comparisons of crop yield advantage from SDI over sprinkler.
• Any changes to cut costs, improve filtration, and decrease maintenance requirements.
• Property taxation classification for SDI needs to be developed to avoid over-taxation where producers currently are being penalized for conserving water. • Why assistance is unavailable to conservation-conscious farmers who want to install SDI, whereas it is available to circle irrigators

FOLLOW-UP
Producers were asked if they would like an in-field analysis of their SDI systems. Approximately 30 responded that they would be willing to participate. Eight individuals were selected for the site visit based on criteria of system age and location. Three systems have been visited and two of those appear to be performing near their original design specifications. The other was suffering from extensive rodent damage, with many large leaks. Leakage was so extensive that no flow was occurring in flush lines. Rodent infestation and lack of timely maintenance has brought the system to the point that abandonment is being considered. The system is still in operation and was installed 0 years ago.

SUMMARY
Most glyphosate labels recommend that ammonium sulfate should be added to a spray solution to counteract effects of hard water and improve weed control. Recommended ammonium sulfate (AMS) rates with glyphosate are relatively high and generally inconvenient to use. Several lowrate water conditioner products are available as alternatives to AMS with glyphosate. Pesticide applicator testimonials suggest performance with those products is inconsistent. Glyphosate control of crop and weed species was enhanced consistently by adding 7 lbs AMS per 00 gallons -in some cases by 40%. Adding 8.5 lbs AMS per 00 gallons to glyphosate generally provided control similar to or slightly less than treatment with 7 lbs AMS. Commercial products with an ammonium sulfate component at the equivalent rate of 8.5 lbs controlled equally to or slightly better than glyphosate plus 8.5 lbs AMS. Commercial water conditioners without AMS or applied at a much lower rate of AMS gave less control than glyphosate with 8.5 lbs or 7 lbs AMS and often were no better than glyphosate alone. Glyphosate tank mixed with low-rate water conditioners did not provide the same level of control compared to the recommended AMS rate.

PROCEDURES
Field experiments were conducted at Manhattan, Garden City, andTribune in 2005 and2006. Roundup WeatherMax at below-labeled rates (8-11 fl oz) was applied to various assay species in combination with the recommended label rates of AMS and various commercial water conditioners. Sprayer application information and stage of plant growth at the time of application are shown below in Table . All control evaluations were made visually on a scale of 0 to 00, with 00 being complete control of the species being rated and 0 being no effect on the species. The rates of the additives are shown at % v/v or as lbs/00G. The % v/v indicates a liquid formulation of the product and refers to gallons of product/00 gallons of spray solution. The lbs/00G indicates a dry formulation and refers to pounds of the dry product/00 gallons of spray solution.

RESULTS AND DISCUSSION
Volunteer wheat was controlled by all Roundup Weath-erMax (glyphosate) treatments regardless of the tank mix partner in the 2005 Garden City experiment two weeks after treatment (Table 2). Roundup WeatherMax (11 fl oz/a) controlled 4-leaf wheat regardless of additive. Palmer amaranth control was 97% when glyphosate was applied with the full load of N PAK AMS at 5% v/v (5 gallon/00 gallon spray solution). This AMS rate is equivalent to 7 lbs dry AMS per 00 gallons of spray solution. Class Act NG enhanced glyphosate efficacy similarly to Alliance, but slightly less than 7 lbs of AMS. Choice, Request, and Guardian Crabgrass 2-4" " Velvetleaf 6-0" 6-8" Sorghum 8" 2-5" 0-2" Corn 24" 2-6" 2-5" Sunflower 2-8" 7-0" 0" Wheat 4-leaf P. Amaranth 2-6" gave less activity with glyphosate than all other products and controlled Palmer amaranth similarly to glyphosate applied alone. Roundup WeatherMax at 8 fl. oz/a applied alone generally gave the lowest control of species evaluated in the 2005 Manhattan experiment (Table 3). Clearly, velvetleaf is the most difficult species to control ,as glyphosate alone gave 40% control. The addition of NPAK AMS at 5% v/v enhanced control of all species with glyphosate compared to glyphosate alone. Class Act NG, Alliance, and N-Tank also enhanced efficacy with glyphosate. The remaining products did not consistently improve control of species evaluated, especially velvetleaf.
Roundup WeatherMax at 8 fl oz/a alone controlled sorghum 56%, corn 74%, and sunflower 84% in the Tribune 2006 experiment (Table 4). NPAK AMS increased the level of control compared to glyphosate alone; however, the full AMS rate of 5% v/v was required to maximize control. All products applied at % v/v or more enhanced control with glyphosate compared to glyphosate alone. N-Tank was the most effective product with a use rate of 0.5% v/v.
Roundup WeatherMax at 8 fl oz/a alone was ineffective on the species evaluated in Manhattan in 2006 (Table   5). The 450 ppm water hardness apparently deactivated the glyphosate. NPAK AMS at 5% v/v enhanced glyphosate dramatically, but control still ranged from only 40% for velvetleaf to 85% for sunflower. All products applied at 0.5% v/v provided little to no enhancement of glyphosate, with the exception of N-Tank, which enhanced glyphosate efficacy slightly, but not equal to NPAK AMS.
In summary, the efficacy of glyphosate consistently was enhanced most by addition of NPAK AMS at 5% v/v (equal to 7 lbs dry AMS / 00 gallon) at all locations in all years. The addition of AMS at 2.5% v/v generally provided similar or slightly less control than with 5% v/v AMS. Commercial products that provided comparable rates of AMS provided a similar enhancement of glyphosate efficacy.
Most commercial water conditioners added at low use rates generally gave much lower weed control than recommended rates of AMS and often were no better than glyphosate alone. The most effective low-rate water conditioner with glyphosate tended to be N-Tank. Under ideal conditions and higher rates of glyphosate, differences in weed control due to adjuvant may be less or even negligible at high levels of weed control.     -   K STATE

INTRODUCTION
With increasing use of glyphosate-resistant corn hybrids, volunteer corn has become a difficult weed to control. Therefore, the objective of these studies was to determine a nonglyphosate tank mix to control this emerging weed problem.

PROCEDURES
Volunteer corn was simulated by planting standard glyphosate-resistant corn hybrids in conventionally randomized complete-block experiments, with four or more replications, conducted near Stillwater, Oklahoma, and Garden City, Kansas. The plot area was kept weed-free with applications of glyphosate as needed. In the first experiment conducted near Stillwater, two-leaf or three-leaf corn was sprayed with 0.05 lbs or 0.03 lbs of clethodim. In a second study three-leaf or six-leaf corn was sprayed with glufosinate, At 0.42 lbs/a or clethodim at 0.06 lbs/a, or paraquat at 0.56 or 0.64 lbs/a or these rates of paraquat tank mixed with 0.5 lbs of atrazine or 0.4 lbs/a metribuzin. The first study at Garden City applied 0, 0.15, 0.03 or 0.06 lbs/a clethodim to four-leaf or eight-leaf corn. In a second study, glufosinate at 0.42 lbs/a or paraquat at 0.28, or 0.56 or 0.64 lbs/a or these rates of paraquat tank mixed with 0.04 lbs/a metribuzin or 0.5 lbs/a linuron were applied to four-leaf or eight-leaf corn.

RESULTS AND DISCUSSION
In Stillwater, two-leaf corn control was 00% at all rates of clethodim. At the three-leaf stage, control declined to 90% with 0.05 lbs/a clethodim. Twice as much clethodim was needed to kill 00% of the three-leaf corn. In a second study, 0.06 lb/a of clethodim was needed to get 00% control of three-leaf or six-leaf corn. In Garden City, as seen in Stillwater, 0.06 lbs ai/a of clethodim controlled more than 90% of the corn 2 DAT, regardless of timing. In contrast, regardless of treatment or timing, all corn recovered to various degrees and was harvested for grain as an index of injury. Although the lowest clethodim rate yielded 6 bu/a more than the control (no clethodim), this was not statistically significant. When 0.015-lb/a of clethodim was applied to eight-leaf corn, yield was reduced from 52 bu/a to 23 bu/a. Clethodim applied at 0.03 lbs/a to four-leaf corn resulted in a yield of 22 bu/a. In contrast, when application of the 0.03lb/a was delayed to the eight-leaf stage, yield dropped to 3.9 bu/a. Regardless of timing of application, corn treated with 0.06 lb/a yielded less than .7 bu/a. Depending on the objectives of a producer, these treatments would have been commercially acceptable.
Although corn was completely defoliated at Garden City by paraquat at rates from 0.28 to 0.64 lb/a by itself or tankmixed with 0.5 lbs/a linuron or 0.4 lb/a or metribuzin, in all instances, the corn recovered and produced a crop that ranged from 23 to 39 bu/a, which was not a statistically significant difference from no treatment. Glufosinate at 0.42 lb/a also produce similar levels of control. Delaying application of these tank-mixes until the eight-leaf stage reduced corn yield from 36 to 2 bu/a. None of these tank-mixes produced a level of control that would be considered commercially viable. At Stillwater, 00% control of three-leaf corn was achieved with Paraquat at 0.57 lb/a tank mixed with 0.4 lb/a or metribuzin or 0.5/a atrazine. Only 44% control of six-leaf corn was seen with any paraquat tank mix. These studies suggest that clethodim, when applied early at lower rates or applied late at the higher rates, might provide the best control of volunteer glyphosate-resistant corn. Oklahoma State University, Stillwater, OK.

SUMMARY
In contrast to winter wheat as a cover crop (as shown by previous research), downy brome (often called cheat) did not consistently affect corn grain yield. During the second and third imposition of treatments on the plot area, downy brome at planting had declined to less than 0% cover. Higher herbicide rates increased corn yield (7.8 bu/a) in only one combination of location and year. The presence of downy brome at planting time depressed corn yield between 3.7 and 12.1 bu/a in two of the five location-year combinations and increased yield by 8.9 bu/a in one location-year. The decision to control downy brome prior to planting is complex and affected other production inputs.

INTRODUCTION
Previous work has shown that a wheat cover crop can improve water-use efficiency (WUE), weed control, and yield of irrigated corn. Therefore, we hypothesized that downy brome may not need to be controlled in irrigated corn if it provides some of the same benefits as a wheat cover crop.

PROCEDURES
A split-plot experiment was established within four blocks, with irrigation as the main plot and a random factorial four-way split consisting of densities of downy brome and two rates of herbicide. The main plots were 20 by 98 feet with 49 by 60-foot subplots. Downy brome was allowed to naturally reseed in the fall of 2003. In March 2004, two of four subplots were treated with 0.75 lb ae/a of glyphosate to remove downy brome. Just prior to planting in the first week of May, the entire plot area was sprayed with glyphosate at 0.75 lbs ae/a and corn was planted at 26,000 kernels per acre across the whole plot area with no-till techniques. Two rates of preemergence herbicides, Isoxaflutole+atrazine+Smetolachlor at .05 +.5+2 lbs/a or at half of this rate, were applied on each of the two levels of downy brome within the larger main plot. Irrigation began when total soil available water in the top four feet was depleted 25-40% in the high water treatments. The high-water treatment simulated a well capacity of 5 gal/min/a to supply a maximum of 2 inches of water per week. The low-water treatment simulated half of the full capacity with a maximum application of inch per week. Corn was harvested when grain moisture dropped below 15.5%. Irrigation-water-use efficiencies (IWUE) were calculated by dividing total corn grain mass by total water applied. The experiment was repeated in 2005 at a separate location. Further, these same treatments were imposed on the same plots at location in 2005 and 2006. The experiment was repeated at location 2 in 2005 and 2006. The third season of location 2 will be executed in the spring of 2007. Johnsongrass was present in the second and third seasons. Therefore, nicosulfuron was applied at 0.03 lb ai/a, or half this rate, to the high-and low-input herbicide plots, respectively.

RESULTS AND DISCUSSION
During the second and third imposition of treatments on the plot area, downy brome at planting had declined to less than 0% cover so impact of this factor was due to the history of brome control, not presence of heavy cover prior to planting. There were no three-way interactions of corn grain yield, irrigation, or herbicide inputs, nor level of downy brome in any of the five location-year combinations. In four of the five location-year combinations, irrigation increased yield from 3.8 to 20 bu/a (Fig. ). The higher herbicide rates increased corn yield (7.8 bu/a) in only one locationyear combination (Fig. 2). The presence of downy brome at planting time depressed corn yield between 3.7 and 2. bu/a in two of the five location-year combinations and increased yield by 8.9 bu/a in one location-year (Fig. 3).
IWUE at location in 2004 and location 2 in 2006 produced a complex interaction of three inputs. At both of these locations, the presence of downy brome at planting did not change IWUE at the high level of irrigation regardless of the level of herbicide input. However, with less irrigation, the presence of brome at planting decreased IWUE, regardless of the level of herbicide inputs at location in 2004 (Fig.  4). In subtle contrast, at location 2 in 2006 (with reduced irrigation inputs and in the presence of downy brome), IWUE increased with added herbicide inputs (Fig. 5). In the other three location-years, IWUE was increased from 3.9 to 5.4 bu/in with reduced irrigation inputs (Fig. 6). More herbicide inputs increased IWUE (0.8 bu/in) in only one of these three location-year combinations (Fig. 7). At a single location, IWUE was depressed (0.2bu/in) by the presence of downy brome at planting (Fig. 8). Clearly, the decision to control downy brome prior to planting is complex and affected other production inputs.

SUMMARY
Six treatments had season-long control of all weeds that was not statistically different from the best treatment. These six treatments had corn yields that were not statistically different from 245 bu/a. Over-irrigation and timely rainfall allowed even the untreated controls to produce a very competitive corn canopy which produced corn yields in excess of 90 bu/a.

INTRODUCTION
With the advent of glyphosate-resistant weeds, the profit potential in herbicide development might be returning to crop protection companies. Therefore, they have begun to release new non-glyphosate herbicides such as the herbicides Impact (topramezone) and Laudis (tembotrione). These emerging herbicides have some similarities to Calisto (Mesotrione) and Balance (Isoxaflutole). Therefore it was the objective of this experiment to compare herbicide standards from the early 990s to Glyphosate tank mixes and these new herbicides.

PROCEDURES
The field was bedded in the fall of 2004 and planted to winter wheat. In the fall of 2005, irrigation furrows were reformed by interow cultivation that left the wheat stubble on top of the beds while removing enough wheat residues to allow efficient furrow irrigation in the spring of 2006. To avoid the poor emergence seen in last year's studies the plot area was prewatered with inches. Due to the level nature of the field and its small size, this excessive amount of water need to be applied to insure uniformity. As any good pessimist could have predicted this excessive irrigation was followed by rain fall that delayed the start of the experiment 0 days past what is often considered the optimum planting date.
Palmer amaranth, yellow foxtail, crabgrass, sunflower, barnyard grass, and shatter cane were seeded at 700,000; 344,24; 9,800,000; 40,000; 87,000; and 9,000 seeds/ acre, respectively, into prepared fields on May 24, just before the corn was planted. All weeds except shatter cane were planted with a carrier mixture of cracked corn at a rate of 40 lb/acre by using a 4-foot Great Plains Drill with tubes removed to allow weed seed to be dropped on the soil surface. Shatter cane was simulated by drilling the forage sorghum 'Rox orange' separately, with every third hole set at inch deep, at 2 inches deep, or with the tube pulled for seed to be dropped on the soil surface. Weed seed was planted in 0-inch rows and soil moisture was ideal.
DeKalb DK-609 RR corn was planted .5 inches deep in 30-inch rows at a rate of 36,000 seeds/acre with a John Deere Max Emerge II planter. The experimental design was a randomized complete block with four replicates. The crop emerged on May 31 prior to the first major flush of weed.
Irrigation was begun before tasseling, on June 28 and 29th. Two inches of rainfall fell in a two-day period on or around the 4th of July. The topography of the field field does not permit run off once irrigation pipe is laid. Therefore all subsequent rainfall and irrigation was absorbed. Although locally derived irrigation models were used to supply enough water to carry the crop to physiological maturity, timely rain fell after many of the irrigation events, which supplied the crop with abundant soil moisture without causing injury to the crop. Corn was combine-harvested and yields were adjusted to 5.5 % moisture.

RESULTS AND DISCUSSION
Enough rain fell within two days of planting to incorporate the preemergence herbicides without crusting in the corn, which allowed the crop to emerge before the first flush of weeds. This was followed by three gentle rains totaling .3 inches at or near crop emergence. This was followed by 15 days with no significant rainfall. This gave the crop a tre-mendous competive edge over the weeds even in the control plots. The corn yield in the control plots were the highest seen in 5 years at this location. (Table). However, the excellent weed control treatments still elevated crop yield 55 bu/A, which would return more than 0 times their cost at current corn prices.

SUMMARY
We tested a foliar fipronil insecticide treatment applied to six soybean varieties to determine effectiveness in reducing Dectes stem borers (Dectes texanus) in soybean. The foliar application of fipronil significantly reduced Dectes stem borer infestations between 76% and 88%. However, these treatments increased yield only 2.9%, and this was not statistically significant. Dectes stem borer infestation averaged 55% infested plants.

PROCEDURES
Seed of six commercial soybean varieties in maturity groups II through to IV was machine-planted at 6 seed per row-foot on May 17, 2005, at the irrigation experiment field near Scandia,. The plots were four rows wide and 20 feet long. There was a 3-foot-wide alley at each end of the plot. The design was a randomized block experiment with three replications. There was a treated and untreated plot of each variety in each replication. The foliar treatment of fipronil was applied July 18 during the beetle flight. This treatment targeted the first two instars developing inside the plants.
The foliar treatment was applied with a backpack sprayer, using a hand-held boom with two nozzles (Conejet TXVS 6) directed at a single row. The nozzles were held 6-8 inches from the plants to maximize coverage of the upper canopy. The sprayer was calibrated to deliver 20 gal/acre (8.0 sec per 20 ft row at 30 psi). A chronometer was used to measure the time spent on each row to help maintain appropriate speed.
The experiment was analyzed as a two-factor experiment with six levels of variety and two levels of treatment.
Dectes stem borer infestations were recorded at the end of the season (September 22) by dissecting five consecutive plants from each of the four rows in each plot for a total of 20 plants. The plants were dissected to record entry nodes, upper stem tunneling, tunneling that reached the base of the plant, and presence of live Dectes larvae. Grain yield data was collected by machine harvesting the plots October 2 and converted to bushels per acre based on 2% moisture.

RESULTS AND DISCUSSION
Dectes stem borer infested 55% of plants in 2006. This was similar to the infestation of 2004, when we were able to show yield responses with fipronil treatment. In this 2006 trial, the fipronil treatment significantly reduced Dectes stem borer infestations (8%, 78%, 82% and 88% for entry nodes, stem tunneling, base tunneling and live larvae, respectively; Table 1). However, the fipronil treatment only increased grain yield 2.9%, and this was not a significant increase. There were some significant differences in Dectes infestation across the different varieties, but there was no significant yield difference across the varieties. This was surprising because there was such a wide difference in maturity across the varieties. The 2006 results suggest there was no physiological yield loss associated with Dectes stem borer infestations. We were not able to show differences in tolerance of the different varieties to Dectes stem borer infestations.

SUMMARY
We tested systemic insecticides applied as seed treatments for their effectiveness in reducing Dectes stem borers (Dectes texanus) in soybean. Fipronil was applied to the foliage later in the season as a positive check based on previous studies. Of the seed treatments tested, only fipronil significantly reduced Dectes stem borer infestations, but it gave 100% control. The foliar application of fipronil also significantly reduced Dectes stem borer infestations, but it gave 85% control. Dectes stem borer infestation averaged 34% infested plants.

PROCEDURES
Soybean seed (Pioneer 93B85, maturity group 3.8) was machine-planted at 0 seeds per row-foot on May 27, 2006, in a half circle of irrigated soybeans of the same variety on the Ramsey Brothers Farm four miles north of Garden City, Kansas. A quantity of seed was sent to be treated with the seed treatments. Other seed without seed treatments was saved and planted in plots designated to receive foliar treatments later in the season or to serve as check plots. The plots were four rows wide and 20 feet long. There was a 3-foot-wide alley at each end of the plot. The original design was compromised when some plots were over-sprayed with insecticides later in the season, so the experiment was analyzed as a completely randomized experiment. We analyzed only those treatments with three or four surviving plots together with 4 check plots and 4 plots receiving the foliar fipronil treatment. The foliar treatment of fipronil was applied August 3, after the plants had recovered from hail damage. This treatment targeted the first two instars of the insect developing inside the plants. The foliar treatment was applied with a backpack sprayer, a hand-held boom, and two nozzles (Conejet TXVS 6) directed at a single row. The nozzles were held 6-8 inches from the plants to maximize coverage of the upper canopy. The sprayer was cali-brated to deliver 20 gal/acre (8.0 sec per 20 ft row at 30 psi). A chronometer was used to measure the time spent on each row to help maintain appropriate speed. For statictical analysis, we used multiple t-test comparisons of the least square means (LSMeans) produced with the SAS-GLM procedure. LSMeans were compared with the check LSMean.
Dectes stem borer beetle populations were estimated by making 00 sweeps across the plants in single rows. Sweep samples were made at irregular intervals during the flight and the numbers were plotted to determine the relationship between the treatment timing and the beetle flight. Dectes larval infestations were recorded at the end of the season (September 8-20) by dissecting 20 plants in each plot. Five consecutive plants were taken from each of the four rows in each plot. The plants were dissected to record entry nodes, upper stem tunneling, tunneling that reached the base of the plant, and presence of live Dectes larvae. When dissected, plants showed very few larvae had tunneled to the base of the plant, so that variable is not reported. Grain yield data was not collected because infestations were low and the plants had been heavily damaged by a hail storm.

RESULTS AND DISCUSSION
Dectes stem borer populations were lower in 2006 than in 2005. On July , a hail storm seriously defoliated the soybeans. This defoliation not only damaged plants, but also knocked off many leaf petioles in which the Dectes beetles had oviposited, thus reducing the potential infestation. The hail also broke or bruised the stems, making it difficult for the larvae to tunnel to the base of the plants. Although the plants recovered, the resulting plants were smaller, later maturing, and more branched than normal. The plants were almost a month late in developing the larger petioles that are attractive to the Dectes beetles. This meant most of the plants escaped Dectes infestation. The Dectes infested an average of 34% of the plants. The delayed development of the Dectes infestation also made it difficult to time the foliar treatment.
Of the seed treatments tested, only fipronil appeared to suppress the Dectes stem borer. It gave 00% control, significantly reducing Dectes stem borer infestations (Table 1). The foliar treatment of fipronil also gave a significant (69-85%) control of the Dectes stem borer. It was clear that the timing of the foliar application was late, because many of the larvae had begun tunneling in the main stem, but were killed there. The fipronil treatment was able to kill larvae tunneling in the main stem and thus prevent them from girdling the plants later in the season. It is hoped the fipronil seed treatments can be registered for use in soybean production, because it appears to be an extremely effective treatment option for the Dectes stem borer.
In 2004, we were able to show a significant difference in yield (4.6 to 6.6 bu/acre) for the fipronil treatments. However, we were not able to take yield data in this trial due to the heavy hail damage and resulting low infestation rate.

SUMMARY
The greatest crop improvements over the past 50 years clearly have occurred in irrigated corn hybrid development. In addition to hybrid improvement, increasing plant populations and improving weed and insect control have been contributors to the increased yields. Irrigated and dryland wheat improvements have trended upward, but year-to-year yield variability continues to plague wheat. Hot temperatures during grain fill, spring freezes, rust, and hail contribute to the variability. In addition, seasonal precipitation variation contributes to variability in dryland wheat varieties. These environmental challenges likely mask yield improvements made in wheat varieties. Irrigated grain sorghum has consistently yielded 00 to 40 bu/a and has a flat yield trend since 1956. Standability and yield potential have been improved, allowing irrigated sorghum growers to harvest standing grain sorghum. Dryland grain sorghum has had a slight upward trend. Hybrid development and improved farming practices contribute to this yield increase. Irrigated soybeans also have a slight upward yield trend. Variety/hybrid performance tests have and will continue to assist the producer making decisions of what varieties or hybrids should be planted. It is always most important to plant more than one variety or hybrid, as well as more than one crop, to minimize production risk due to environmental and economic conditions. PROCEDURES Crop variety/hybrid performance tests, irrigated corn, irrigated wheat, dryland wheat, irrigated grain sorghum, dryland grain sorghum, and irrigated soybeans have been conducted at the SWREC annually over the past 50 years. For each crop, the varieties/hybrids yields were averaged for each year from 956 through 2006. These trial averages were regressed against year to measure the level of crop yield improvement throughout the 50-year period.

RESULTS AND DISCUSSION
Advancements in irrigated corn yields since 956 have exceeded all other crops evaluated during the same period of time at the SWREC. Regression analysis of the irrigated corn performance test averages predicts that irrigated corn yields have increased 2.2 bu/a/year (Figure ). The development of corn hybrids, as well as fertility, plant population increases, improved weed control practices, and genetically modified organism GMO corn borer resistance have all contributed to the increased corn yields. Annual average yields are shown on Figure . The lowest average yields were less than 00 bu/a in 956 and 957, while the two highest average yields occurred in 2002 and 2003 (both exceeding 250 bu/a).
Irrigated wheat has had a slight upward trend over the 50-year period (Figure 2). The regression predicts wheat yield improvements of 0.28 bu/a/year from 956 through 2006. Although huge improvements have been made on wheat standability, earlier maturity, disease resistance, and variety yield potential, environmental conditions continue to control wheat yields, resulting in significant year-to-year variation. High temperatures during grain fill, freeze damage, rust, and hail contribute to low-yielding years. Omitting the zero yielding years, two years had average yields of less than 30 bu/a and two years have had average yields exceeding 80 bu/a. Dryland wheat, like irrigated, has had a similar upward trend of 0.25 bu/a/yr (Figure 3). Growing-season precipitation variability, along with spring freezes, high temperatures during grain fill, rust, and hail contribute to large variability in dryland wheat yields masking the true increase in wheat variety yield potential improvement. The long term yields indicate that we raise wheat in a harsh environment. In only 7 years since 956 has the dryland wheat variety trial averaged more than 40 bu/a. In fact, 2 years have had average yields of 20 bu/a or less. This includes 967, 979, 987, and 996, when the dryland wheat variety trial was abandoned.
Irrigated grain sorghum yield does not trend upward but remained flat from 1956 through 2006 (Figure 4). The excellent yields in the 950s and '60s perhaps were higher than farmer yields because plots were primarily hand harvested. Varieties and hybrids at that time were prone to lodging, which significantly reduced the amount of crop a producer could machine harvest. Improvements have been made in sorghum standability and hybrids have been shortened in height. They also possess improved stalkrot resistance, which has allowed producers to harvest standing irrigated grain sorghum, resulting in increased harvested yields. Greater variation in sorghum yield has occurred since 983. Four years of the irrigated sorghum hybrid trials have been abandoned, including three years to hail (967, 979, and 992) and one to freeze (983) . It is amazing that the irrigated hybrid sorghum yield averages have equaled or exceeded 00 bu/a in all but four years that yield data has been collected; yet, in only three years did the average irrigated sorghum yield exceed 40 bu/a. From 957 through 2006, irrigated sorghum has consistently yielded 00 to 40 bu/a.
Dryland grain sorghum (conventional tilled sorghum/fallow) yield has trended upward 0.67 bu/a/year ( Figure 5). The trend is a result of hybrid improvements for dryland, as well as improved farming practices for fertility and weed control. Since 990, the occurrence of average yields exceeding 80 bu/a has increased. Like dryland wheat, year-toyear variation is high due to variability in precipitation and other environmental challenges, such as hail.
Irrigated soybean yields have had a slight upward trend of 0.22 bu/a/year ( Figure 6). In 984, the soybean variety trail was split into Group II & III or Group IV bean experiments and remained in that format until 2002. Data in Figure 6 from the periods prior to 984 and after 200 include all groups of soybean varieties. The Group IV bean variety averages remained flat from 1984 through 2001 (Figure 7).

ACKNOWLEDGMENTS
The staff of the Southwest Research-Extension Center and Kansas State University appreciate and acknowledge the following companies, foundations, and individuals for their support of the research that has been conducted during the past year.