Southwest Research-Extension Center, Field Day 1999

Report of agricultural research from Southwest Research-Extension Center of Kansas State University.


Southwest Research-Extension Center
Once again, we had a wet year; in fact, 1998 was the tenth consecutive year with above average precipitation. Precipitation totaled 22.19 inches compared to 17.91 inches for the 30-year average. We accumulated 14.49 inches of growing-season precipitation (April -September) compared to 13.90 inches in an average year. July had 6.61 inches precipitation, which was the wettest July since 1958 and the third wettest since our records began in 1908. January was the driest month in 1998 and the driest January since 1986. Snowfall was light, measuring 12.15 inches, which was 5.55 inches below average. Measurable snowfall was recorded only in January, March, and December.
As usual, July was the warmest month in 1998 with an average temperature of 79.3°. This was the warmest July since 1986. January was the coolest month with an average temperature of 32.6°, slightly above the normal January temperature of 27.9°.
Daily minimum temperatures below zero were recorded on 4 consecutive days starting on December 22 and ending on Christmas day, with the low of -12°o n December 22. Temperatures of 100° or above were recorded on 20 days in 1998, with the highest of 107° on June 27.
Six record high temperatures were broken or tied in 1998. They were: 100ϒ on May 31, 107ϒ on June 27, 99ϒ on September 26, 94ϒ on September 27, 97ϒon September 30, and 79ϒon November 25. No record low temperatures occurred.
The last spring freeze (32ϒ) occurred on April 30, 4 days later than average. The first fall freeze (31ϒ) fell on October 18, 6 days later than average. The resulting frost-free period was 171 days compared to 169 days average.
Open pan evaporation from April 1 through October 31 totaled 69.38 inches. This is similar to the 73.76 inches average. Mean wind speed was 4.65 mph, considerably less that the 5.5-mph average.  ) calculated from National Weather Service. Average temperature, latest freeze, earliest freeze, wind, and evaporation are for the same period calculated from station data.
Precipitation for 1998 totaled 17.49 inches, which is 1.53 inches above normal. Precipitation was above normal in 5 months. July was the wettest month with 6.53 inches, which was 3.93 inches above normal, and January was the driest month with only 0.04 inch precipitation. The largest single amount of precipitation was 1.93 inches on July 25, and a total of 3.17 inches was recorded for the 4-day period July 23 through July 26. Measurable snowfall occurred in only 3 months; January with 1.0 inches, March with 6.75 inches, and December with 7.25 inches. Snowfall for the year totaled only 15.0 inches with a total of 14 days of snow cover. The longest consecutive period of snow cover, 7 days, was from December 20 to December 26.
The air temperature was above normal for 8 months of the year, with July being the warmest month with a mean temperature of 77.1°, and the average high temperature was 92.2°. The coldest month was December with a mean temperature of 30.4°, average high was 45.9°, and average low was 14.8°. Record high temperatures were set on March 26 and 27; April 12; May 31; June 27; September 26; and November 23 and 29. Record low temperatures were set on April 17; and June 6 and 18. Deviation from the normal was greatest in September, when the mean temperature was 6.0° above normal. Temperatures were 100° or above 15 days, compared to the 30-year average of 10 days, and 90° or above on 57 days, compared to the 30-year average of 63 days. The lowest temperature for the year was -15°o n December 22, and the highest was 106° on July 21. The last temperature of 32° or less was on June 6, 34 days later than normal, but no crop damage was apparent. The first temperature of 32° or less in the fall was on October 6, 3 days later than the normal date. The frost-free period was 122 days, which is 31 days less than the average of 153 days.
Open pan evaporation from April through September totaled 69.87 inches, which is 1.80 inches below normal. Wind speed for the same period averaged 4.8 mph, 0.9 mph less than normal.

INTRODUCTION
Fully irrigated corn in western Kansas usually consists of full-season hybrids (115 day or later) grown at populations of 30,000 to 35,000 plants/a. Research has shown no advantages to shorter-season corn in terms of yields, average water use rates, and water use efficiencies. Full irrigation of corn has been proven to be more profitable than limited irrigation. However, some farmers are converting irrigated acres to dryland because of declining groundwater. Very limited irrigation, meaning once or twice a season, may enable these farmers to conserve the remaining groundwater, while still producing adequate yields. The objective of this study is to determine whether very limited irrigation is an alternative to returning acres to dryland.

PROCEDURES
Two corn hybrids having maturities of 104 and 115 days were planted on May 13, 1998 at seeding rates of 18,000 and 33,000 seeds/a. The corn was planted in the stubble remaining from the 1997 wheat crop, following about 11 months of fallow. Single irrigation treatments were at the 8-leaf stage, and two irrigations were at the 8-leaf and tassel stages. Each irrigation consisted of 6 inches of water applied through gated pipe. A dryland treatment was included. The plots were bordered to prevent runoff.

RESULTS AND DISCUSSION
Results are presented in Table 1. Populations were somewhat lower than desired, 15,000 and 25,000 plants/a for the early hybrid and 17,000 and 27,000 plants/a for the later hybrid. Yield of the early hybrid increased with population at each irrigation level. Yield of the later hybrid was reduced by the high population in the dryland plot and increased only slightly with one irrigation. With two irrigations, yield of the later hybrid increased 25 bu/a at the high population. The later hybrid yielded more than the earlier hybrid at the low population when not irrigated, and at both populations when irrigated once or twice. Both hybrids produced similar yields with dryland and high population.
The corn was stressed prior to tassel by lack of rainfall. The combination of irrigation and rainfall during the remainder of the growing season resulted in excellent yields. As in previous studies, the later maturing hybrid produced the most grain. However, results may differ in years of less rainfall. Bracketed numbers indicate days to maturity.
LSD (0.10) Hybrid at same irrigation and population 13 Irrigation at same hybrid and population 12 Population at same hybrid and irrigation 9

INTRODUCTION
The wheat-sorghum-fallow rotation produces more grain and is more profitable than the wheatfallow rotation. A logical step up from wheatsorghum-fallow is wheat-corn fallow. Corn traditionally is thought to lack sufficient heat and drought tolerance for dryland production in southwest Kansas. However, research at Garden City indicates that dryland corn may be feasible, if attention is given to hybrid, planting date, and plant population. No-till has proven to be essential for adequate yields in dry years and has increased yields substantially in wet years. This no-till dryland corn study compares hybrids of five different maturities planted on two dates at three plant populations. The objectives of this study are to determine the corn maturity class, planting date, and plant population, or, more likely, a combination of these factors, that will allow successful dryland corn production in southwest Kansas.

PROCEDURES
Dryland corn was grown in the wheat-corn-fallow rotation in 1996 through 1998 to compare different maturity hybrids at different planting dates and plant populations. Five Pioneer hybrids having days to maturity of 75, 92, 98, 106 and 110 were planted in mid-April and early May each year. The two earliest hybrids were not planted in 1996. Populations were 12,000; 18,000; and 24,000 plants/a. The hybrids were no-till planted into the stubble remaining from the previous wheat crop.

RESULTS AND DISCUSSION
Results are given in Table 1. Yields of hybrids in 1996 increased with plant population. The 110-day hybrid produced the most yield, particularly at the highest population. Yields were improved by later planting, probably because of more favorable weather conditions. Yields were improved drastically by later planting in 1997, sometimes more than 100%. Hybrids planted on the second date were able to take advantage of rainfall that came too late for the earlier planting. The 110-day hybrid again produced the most grain, but yields were reduced at the high population. Results from the first and second planting dates in 1998 were similar to those of 1996, with corn planted on the second date yielding more. The 75-day hybrid was the lowest yielding on both dates. This hybrid apparently did not have enough yield potential to utilize the more favorable weather conditions following the later planting date.
Early planting can increase irrigated corn yield, and dryland yield, if there is no stress. Under dryland conditions in western Kansas, however, yield is determined by weather conditions, and rainfall distribution is most important. The best yield will result from the planting date followed by the best rainfall distribution. Thus far in this study, that has been the later of the two planting dates, but this could easily change if good rainfall distribution follows the first date, and poor distribution follows the second date. Yields also will increase with increasing maturity and higher plant populations, provided rainfall is 6 sufficient. However, higher populations use more soil water, or, at least, water is depleted faster than at a lower population. The results of dryland corn research done so far support a population of 18,000 plants, with the qualification that yields in dry years may be reduced compared to those of lower populations. The results of this and other studies also indicate that the yield reduction from a population too high in dry years is less than the yield reduction resulting from a population too low in wet years.

INTRODUCTION
Dryland corn is not as drought and heat tolerant as grain sorghum. For dryland corn to yield well, particular attention needs to be given to hybrid maturity, planting date, and plant population. Because the yield of dryland corn depends on stored soil water and growing season rainfall, it probably should be planted where maximum accumulation of water can occur. This study was designed to compare the yield of corn grown on a slope with that grown on flat land.

PROCEDURES
Five Pioneer hybrids of 92-, 98-, 106-, and 110day maturities were planted on sloped and flat plot areas in a wheat-corn-fallow rotation. The hybrids were planted in the stubble remaining from the 1996 and 1997 wheat crops. Planting dates were April 23, 1997 andMay 8, 1998. The planting rate was 18,000 seeds/a. Actual populations were closer to 12,000 plants/a in 1997 because of crusting. About 16,000 plants/a emerged in 1998.

RESULTS AND DISCUSSION
Yields are presented in Table 1. Growing season rainfall was above average in both years, but rainfall distribution was poor in 1997, particularly in July. Yields were variable in 1997 because of nonuniform stands and did not differ significantly between hybrids. Yields were from 31 to 53 bu/a higher on the flat plot area. Average yields were only 27 bu/a on the slope vs. 68 bu/a on the flat plot area. Less water was stored during fallow on the sloped area, and much of the rainfall ran off, reducing yield. Water ran onto the flat area, increasing yield. Yields were much better in 1998, but average yields were still 14 bu/a higher on the flat area. Yields generally increased with hybrid maturity in 1998, particularly on the flat area. Preliminary conclusions are that yields of dryland corn in dry years will be reduced substantially on sloped land. In years of low rainfall, less water will be stored on a slope, and much of the growing season rainfall will run off.

SUMMARY
Grain yields of wheat and grain sorghum increased with decreased tillage intensity. Yields for no-till wheat were 7 bu/a higher than those for conventionaltill, whereas reduced-till yields were 4 bu/a higher than those for conventional tillage. Grain sorghum yields for no-till and reduced-till also were considerably higher than those for conventional tillage. Production costs also increased with reduced tillage. The increased wheat yields were offset by these increased costs, resulting in returns being only slightly higher for no-till. However, the increased grain sorghum yields associated with reduced and no-till resulted in higher net returns.

INTRODUCTION
In the semi-arid regions of western Kansas and the Great Plains, research has shown that reduced tillage often has resulted in increased grain yields. Increased grains yields offer the opportunity for increased returns. This study was conducted to determine the economic impact of reducing tillage based on 8 years of agronomic data from Tribune, Kansas.

PROCEDURES
Research on different tillage intensities in a wheatsorghum-fallow rotation at the K-State Southwest Research-Extension Center at Tribune was conducted from 1991-1998. The three tillage intensities were conventional, reduced, and no-till. The conventionally tilled rotations were tilled as needed to control weed growth during the noncrop period. On average, this resulted in four tillage operations per year, usually with a blade plow or field cultivator. The reduced tillage rotations used a combination of herbicides and tillage (one to three tillage operations) to control weed growth during the noncrop period. The no-till rotations exclusively used herbicides to control weed growth during the noncrop period. All tillage systems used herbicides for in-crop weed control.
The actual tillage operation and herbicide application for each year of the study was used to determine the production costs for the three tillage intensities. These costs were based on average custom rates for southwest Kansas. Custom rates also were used for planting, harvesting, and fertilizer application costs. The remaining costs, including seed, fertilizer, and herbicides, were based on historical costs over the study period. Wheat and grain sorghum prices were average yearly prices for southwest Kansas from 1991 to 1998. Land costs and government payments were not included in the study.

RESULTS AND DISCUSSION
On average, wheat yields over the 8-year period were higher for no-till than for reduced and conventional tillage ( Figure 1). However, in some years, no-till wheat yields were less than or approximately equal to those for reduced and conventional tillage. Production costs, like yields, were also higher for no-till, resulting in returns being only slightly higher for no-till ( Figure 2).
Grain sorghum yields for reduced-till averaged 19 bu/a more than yields for conventional tillage ( Figure 3). Over this same time period, no-till yields averaged 5.5 bu/a more than reduced-till yields. Thus, there is a greater advantage to reducing tillage with grain sorghum than wheat. Similar to wheat, production costs for grain sorghum increased as tillage decreased. Figure 4 shows the sorghum tillage and herbicide cost components for conventional, reduced, and no-till. Although tillage costs decreased with reduced tillage, herbicide costs increased to a greater extent; therefore, total costs/a increased. Nevertheless, even with increased production costs, no-till sorghum returns were nearly twice those of conventional-tillage sorghum ( Figure 5). According to Figure 6, which includes both wheat and sorghum returns, the no-till rotation was clearly the most profitable. The returns per tillable acre for no-till, reduced-till, and conventional-till were $46.67, $42.55, and $29.71, respectively.    1991 1992 1993 1994 1995 1996 1997 1998 1991 1992 1993 1994 1995 1996 1997 1998 Ave  1991 1992 1993 1994 1995 1996 1997 1998

SUMMARY
Soil chemical properties were measured in irrigated fields in western Kansas with a history of animal waste applications. The fields varied in the type of waste applied (solid cattle manure or effluent water from swine or cattle wastewater lagoons) and the duration of application (from 3 to 30 years). At most sites, soil phosphorus (P) levels were increased (up to 150 ppm) by waste applications, indicating that application rates exceeded crop P demands. The highest P concentration in the surface soil (0 to 6-inch depth) was 200 ppm Bray-1 P, which is the maximum level established for continued application of swine waste. Soil nitrate levels also were increased (as much as 100 ppm) by waste applications. At some sites, considerable nitrate (30 to 50 ppm) had leached past the crop root zone to a depth of at least 10 feet.

INTRODUCTION
Application of animal wastes can enhance soil chemical and biological properties and serve as a valuable nutrient source for crop production. However, improper use of animal manure can adversely affect the environment. Two concerns associated with land application of animal waste are phosphorus (P) loss in surface water runoff, which causes eutrophication of streams and lakes, and nitrate leaching through the soil profile into the groundwater. The purpose of this study was to sample fields that have received land application of animal wastes and compare the soil chemical properties to similar fields that have not received manure applications.

PROCEDURES
Soil samples were collected from seven irrigated fields in western Kansas (in cooperation with local landowners) that had a history of manure application. The type of manure, number of years of application, and application method varied among sites. The application rate was unknown for most sites. The longest history of application was about 30 years. Two sites received swine wastes (effluent water) and the others received cattle manure (two sites received solid manure and three sites received effluent water). Each field was divided into three subfields. In each subfield, three soil cores to a depth of 10 ft were collected; divided into 12-inch increments (except for the surface foot), and composited. For the surface foot of soil, 6 additional cores were collected; divided into 0-to 2-inch, 2-to 4-inch, 4-to 6-inch, 6-to 8inch, and 8-to 12-inch increments; and composited. Similar fields that had not received manure (identified by the landowner) also were sampled in the same manner. The samples were dried and sent to the KSU Soil Testing Laboratory for analyses.

RESULTS AND DISCUSSION
Soil P levels were increased to about 200 ppm Bray-1 P (0-to 6-inch depth) in a field that had received manure for about 30 years (Table 1). In an adjacent field that had not received solid cattle manure, the soil P level was about 45 ppm. Soil nitrate levels also were considerably greater in the manured field (Table 2), with some accumulation below the crop root zone (generally about 5 ft). For instance, soil nitrate was 32 ppm in the 9-to 10-ft depth in the manured field compared to less than 1 ppm in the nonmanured field. At the second site that received solid cattle manure, soil P levels were about 180 ppm following three annual application of cattle manure (20 ton/year); however, similar soil P levels were observed in an adjacent area that had not received manure in the past 3 years. Also, at this site, soil nitrate levels were similar for both the manured and the control field, with considerable nitrate throughout 12 nitrogen would be readily available for crop growth. However, some movement of nitrate was observed below 5 ft, with 25 ppm nitrate in the treated area compared to 11 ppm in the untreated area.
Two sites were sampled that had received applications of effluent water from swine lagoons. At the site with the longest history of application (since 1970), soil Bray-1 P levels were about 135 ppm averaged across the top 6 inches of soil (Table  1). Considerable accumulation of nitrate occurred in the soil profile, with the highest concentration (170 ppm nitrate) at the 5-to 6-ft depth (Table 2). Nitrate had leached past the crop root zone; about 59 ppm occurred at the 9-to 10-ft depth. At another site that had received effluent water for about 8 years, soil P levels were about 70 ppm. Similar to the previous site, the highest level of soil nitrate (120 ppm) was at the 5-to 6-ft depth. Soil nitrate levels were also above 100 ppm in the 6-to 8-ft depths. Below 8 feet, soil nitrate levels decreased to 34 ppm in the lowest depth (9 to 10 ft). A concern with application of swine waste is accumulation of heavy metals (copper and zinc) in the soil that can have phytotoxic effects on crops. For these two sites, heavy metal accumulation was not a problem; DTPA-extractable Cu was less than 2 ppm, and DTPA-extractable Zn was 4 ppm. the soil profile (40 to 50 ppm at the 9-to 10-ft depth). Three fields were sampled that had received effluent water from wastewater lagoons at cattle facilities. The impact of effluent water application varied considerably among the sites. Soil P levels at the site with the longest history of effluent water application (about 15 years) were about 120 ppm (Table 1). Soil nitrate levels also were elevated at this site, with over 50 ppm nitrate in the 5-to 10-ft depths (Table 2). At another site, soil P levels were relatively unchanged following 10 years of effluent water application (about 37 ppm Bray-1 P for manured and nonmanured fields). However, the effluent water did increase soil nitrate levels; about 17 ppm nitrate occurred in the 5-to 10-ft depth in the field receiving effluent water compared to about 1 ppm in the control field. At a third site that had received effluent water for only 3 years, soil P levels were increased to about 115 ppm compared to about 10 ppm in an adjacent area that had not received effluent water. Soil nitrate levels were increased by effluent water application, but mostly in the upper profile. For instance, in the top foot of soil, the nitrate level was more than 100 ppm in the field receiving effluent water compared to less than 5 ppm in the area not receiving effluent water. This 13 SUMMARY Long-term research shows that phosphorus (P) and nitrogen (N) fertilizers must be applied for optimum grain yields of irrigated corn and grain sorghum in western Kansas. In this study, N and P fertilization increased corn yields more than 100 bu/ a. Application of 160 lb N/a tended to be sufficient to maximize corn yields. Phosphorus increased corn yields by 75 bu/a when applied with at least 120 lb N/ a. Application of 40 lb P 2 O 5 /a was adequate for corn, and higher rates were not necessary. Grain sorghum yields were increased over 40 bu/a by N and about 20 bu/a by P fertilization. Application of 80 lb N/a was sufficient to maximize yields in most years. Potassium fertilization had no effect on sorghum yield.

INTRODUCTION
This study was initiated in 1961 to determine responses of continuous corn and grain sorghum grown under flood irrigation to N, P, and potassium (K) fertilization. The study is conducted on a Ulysses silt loam soil with an inherently high K content. Because corn did not respond to K, it was discontinued in 1992. However, a yield increase from P fertilization has been observed since 1965, and concern has existed that the level of P fertilization might not be adequate. So, beginning in 1992, a higher P rate was added to the corn study.

PROCEDURES
Initial fertilizer treatments in 1961 to corn and grain sorghum in adjacent fields were N rates of 0, 40, 80, 120, 160, 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. In 1992, the treatments for the corn study 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 3379 (1992-94), Pioneer 3225 (1995-97), and Pioneer 3395IR (1998) planted at 32,000 seeds/a in late April or early May. Sorghum (Mycogen TE Y-75 from 1992-1996, Pioneer 8414 in 1997, and Pioneer 8505 in 1998 was planted in late May or early June. Both studies were furrow irrigated to minimize water stress. The center two rows of all plots were machine harvested after physiological maturity. Grain yields were adjusted to 15.5% moisture for corn and 12.5% for sorghum.

RESULTS AND DISCUSSION
Nitrogen and P fertilization increased corn yields averaged across the 7-year period by over 100 bu/a. In 1995, hail during the growing season reduced overall yields about 40%, but yields were still increased up to 80 bu/a by N and P fertilization. The apparent N fertilizer requirement was about 160 lb/a. Application of 40 lb P 2 O 5 /a increased yields more than 70 bu/a when applied with at least 120 lb N/a. No significant yield difference occurred between applications of 40 and 80 lb P 2 O 5 /a, averaged across all N rates. However, at 160 and 200 lb N/a, corn yields were 4 bu/a greater with 80 than with 40 lb P 2 O 5 /a. Grain sorghum yields were increased 43 bu/a by application of 80 N/a, averaged across the last 6 years. Phosphorus increased sorghum yields by about 20 bu/a, but K had no effect on sorghum yields.

SUMMARY
Yields were lower for second crops of wheat and sorghum in a wheat-wheat-sorghum-fallow and wheatsorghum-sorghum-fallow rotation than for the first crops. However, the difference was smaller for wheat than for sorghum. The second-crop grain sorghum yields were much more variable than second-crop wheat yields in these 4-year rotations. Returns per acre were highest for the wheat-wheat-sorghum-fallow rotation, followed by wheat-sorghum-fallow and INTRODUCTION Research in western Kansas has shown that increasing cropping intensity from a wheat-fallow rotation to a wheat-summer crop-fallow rotation can increase economic returns. Besides increasing returns through increased acres planted, increased cropping intensity also can be beneficial by reducing production and marketing risks through diversification and by reducing erosion. This study determined the economic feasibility of implementing 4-year crop rotations. The rotations evaluated were wheat-wheat-sorghum-fallow and a wheat-sorghum-sorghum-fallow.

Procedures
This study was initiated in 1995 at the Southwest Research-Extension Center in Tribune, KS. Complete yield data for the wheat-wheat-sorghum-fallow (WWSF) and wheat-sorghum-sorghum-fallow (WSSF) rotations were available for 1997 and 1998. Tillage was used initially during summer-fallow prior to the first wheat crop, but both rotations were exclusively no-till in 1998. To determine the production costs for each rotation, average custom rates for southwest Kansas were used for tillage operations, herbicide applications, fertilizer applications, planting, and harvesting. Average 1997 and 1998 costs were used for fertilizer, seed, and herbicides. The market prices for wheat and sorghum in 1997 and 1998 were average prices in southwest Kansas. Land costs and government payments were not included.
Although a separate wheat-sorghum-fallow (WSF) rotation was not included in the study, the two 4-year rotations were compared to a WSF rotation by using the net returns for wheat and the first sorghum crop in the WSSF rotation. Thus, we could determined whether it would be more profitable to increase cropping intensity from two crops in 3 years to three crops in 4 years.

RESULTS AND DISCUSSION
The wheat yields in the WWSF and WSSF rotations are shown in Fig. 1. In all three cases, wheat yields increased from 1997 to 1998. In both years, the second-crop wheat yielded lower than wheat following fallow, but in 1998, the difference was only 1 bu/a. The sorghum yields for the WWSF and WSSF rotations are shown in Fig. 2. The first-year sorghum yields in the WSSF rotation were the highest in both years. The sorghum yields, like the wheat yields, were higher in 1998 than 1997. However, the second-crop sorghum yields in the WSSF rotation were more variable than those of the first sorghum crops. In fact, these yields varied from 45 bu/a in 1997 to 100 bu/a in 1998. Fig. 3 shows the returns per tillable acre for the WWSF, WSSF, and WSF rotations. On average, the WWSF rotation had the highest net return at $72.76/ a. However, the difference between this rotation and the WSSF and WSF rotations was not large. The WSF rotation had returns of $68.00/a, and the WSSF rotation returned $66.75/a. Fig. 4 illustrates the yields at three price levels needed in the second wheat crop in a WWSF rotation to break even with a WSF rotation. Focusing on the middle price level of $3.30/bu, 35 bu/a would be needed in the second wheat crop if wheat yielded 40 bu/a in a WSF rotation. With lower wheat prices, higher yields are needed in a second wheat crop to break even with a WSF rotation. This occurs because the sorghum acres, which have higher returns than wheat, are reduced. The situation is similar for sorghum (Fig. 5). If the WSF sorghum yield is 80 bu/a, 65 bu/a would be needed in the second sorghum crop in WSSF rotation to break even with the WSF rotation, given that the sorghum price was $2.20/bu.

SUMMARY
Using subsurface drip irrigation (SDI) with lagoon wastewater has many potential advantages. The challenge is to design and manage the system to prevent emitter clogging. A study was designed and conducted in 1998 to test the operation of five types of driplines (with emitter flow rates of 0.15, 0.24, 0.40, 0.60, and 0.92 gal/hr/emitter) with lagoon wastewater. Filtration was with a disk filter (200 mesh), and shock treatments of chlorine and acid were injected periodically. Nearly 21 inches of wastewater were applied through the system from June to September. Flow rates of the two lowest flow-rate emitter treatments (0.15 and 0.24 gal/hr/ emitter) decreased by 15 and 11% of the original flow rates, respectively, indicating that some emitter clogging had occurred. Only a fraction (5%) of the original flow rate was reclaimed in the 0.24 gal/hr/ emitter plots, and none in the 0.15 gal/hr/emitter plots. The three highest flow-rate emitter treatments showed no signs of clogging; their flow rates did not decrease through the season. Long-term effects (>1 growing season) of wastewater on SDI have not yet been tested. The disk filter and automatic backflush controller performed adequately in 1998. Based on these results, the use of SDI with lagoon wastewater shows promise, but the smaller emitter sizes may not be appropriate.

INTRODUCTION
Use of subsurface drip irrigation (SDI) with water from animal waste lagoons has many potential advantages. They include, but are not limited to, reduced human contact with wastewater; no runoff of wastewater into surface waters; placement of phosphorus-rich water beneath the soil surface where runoff potential is reduced; greater water application uniformity resulting in better control of the water, nutrients, and salts; reduced irrigation system corrosion; reduced climatic-based application constraint (especially high winds and low temperatures); and increased flexibility in matching field and irrigation system sizes.
Very small emitters in SDI systems may be prone to clogging by the various constituents of the wastewater. The worldwide leading cause of microirrigation system failure is emitter clogging. The design and management challenge of using SDI with wastewater is to prevent emitter clogging. Given that challenge, the objective of this project was to measure the performance of five different dripline types as affected by irrigation with filtered but untreated water from a beef feedlot runoff lagoon.

PROCEDURES
This project was conducted at Midwest Feeders, Ingalls, KS, a beef cattle feedlot.
In April 1998, driplines were installed 17 inches deep and on a lateral spacing of 60 inches. Each plot was 20 ft wide (four driplines) and 450 ft long. The system installation was completed and the first wastewater was used for irrigation on June 17. After completion of the system, the lagoon wastewater was the only water applied with the SDI system. No clean water was used for irrigation, flushing, or dripline chemical treatment. Each dripline type was replicated three times, and two border plots were included, giving a total of 17 plots.
Five drip irrigation lateral line (dripline) types, each with a different emitter flow rate (and thus different emitter size), were tested. Emitter flow rates 20 were 0.15, 0.24, 0.40, 0.60, and 0.92 gal/hr/emitter. This wide range of emitter flow rates was selected to determine the optimum emitter size that would be less prone to clogging when used with lagoon wastewater. Agricultural designs of SDI in the Great Plains with fresh, clean groundwater typically use lower flow rate emitters.
The wastewater was filtered with a plastic grooveddisk filter, and the flow capacity was based on the filter manufacturer's recommendations. The disks were selected to provide 200-mesh equivalent filtration even though the manufacturer's recommendation for all driplines was filtration of 140 mesh or finer. A controller was used to automatically backflush the filter after every hour of operation or when the differential pressure across the filter reached 7 psi. Acid and chlorine also were injected into the system on July 9, July 27, August 4, August 31, September 4, October 6, and November 17 to help keep bacteria and algae from growing and accumulating in the driplines and to clean lines of existing organic materials. Acid was added to reduce the pH to approximately 6.3. Driplines were flushed on August 4, September 2, October 6, and November 17.
To test the system, irrigations of 0.20 to 0.40 inches were applied daily from June through early September. Each plot received the same application amount for a given day, so the run times for plots varied according to their emitter flow rates and emitter spacings. Each plot received the same seasonal application amount of nearly 21 inches. This amount is in excess of the typical crop water requirement but allowed a more thorough test of the SDI system. Following the final corn irrigation on Day of Year (DOY) 247, the system was not used until DOY 279, 280, and 321, when the system flow rates were tested.
Emitter flow rates for entire plots were measured weekly. Pressure gauges at the head and tail ends of the plots were used to measure the pressure within the driplines. Totalizing flow meters measured the amount and rate of wastewater delivered to each plot.
To test the flow rate of the driplines in an entire plot, the flow amount to each plot was measured and timed for approximately 30 minutes. Inlet and flushline pressures were recorded. To account for the variation due to fluctuating pressures from test to test, the inlet pressure was normalized to the design pressure using the manufacturer's emitter exponent for the dripline.

PRELIMINARY RESULTS
The three higher-flow emitter sizes (0.4, 0.6, and 0.92 gal/hr/emitter) showed little sign of clogging (Fig. 1). Flow rates at the end of the season for those emitters were within 2% of the initial flow rates, indicating that very little emitter clogging and resultant decrease of flow rate had occurred. The absence of emitter clogging indicates that emitters of these sizes may be adequate for use with lagoon wastewater.
The two lower-flow emitter sizes (0.15 and 0.24 gal/hr/emitter) showed some signs of emitter clogging (Fig. 1). Within 30 days of system completion, the flow rates of plots with both lower-flow emitters began to decrease. The 0.15 gal/hr/emitter plots showed a gradual decrease of flow rate throughout the remainder of the test. By DOY 321, the flow rate had decreased by 15% of the initial flow rate. The 0.24 gal/hr/emitter plots showed a decrease of flow rate of 11% of the initial flow rate by DOY 245. Following harvest and the first (32-day) idle period, flow rates in the 0.24 gal/hr/emitter plot increased approximately 5% over the minimum measured flow rate. This increase indicated that some cleaning of the emitters had occurred in response to the flushing. The flow rate then stabilized for the rest of this test at about 9% less than the initial flow rate.
The disk filter and automated backflush controller operated well in 1998. Based on our observations, the hourly backflush frequency was adequate to prevent excessive differential pressure accumulation, and the set point of 7 psi was never reached.

CONCLUSIONS
These results show that the drip irrigation laterals tested with SDI have potential for use with lagoon wastewater. However, the smaller emitter sizes normally used with groundwater sources in western Kansas may not be appropriate for use with lagoon wastewater, because they may be prone to clogging.
The results of this study, while very encouraging, should be considered preliminary. Questions still remain about the long-term, multiseason performance of SDI systems using livestock wastewater. Efficient long-term performance probably will be necessary to justify the higher investment costs of SDI systems.

FIELD APPLICATION OF ET-BASED IRRIGATION SCHEDULING IN WESTERN KANSAS 1
by Mahbub ul Alam, Todd Trooien, and Danny Rogers 2 SUMMARY Irrigation-scheduling demonstration fields planted to corn were set up in nine counties in southwestern Kansas. Each site was equipped with soil-water sensors at two locatioins and placed at three depths. Soil samples were taken to evaluate soil water. Neutron access tubes were installed at two sites with different soil textures. Evapotranspiration (ET) data from the weather station at the Southwest Research-Extension Center were used to calculate water balance. The Southwest Kansas Groundwater Management District #3 installed 12 weather stations that make ET data available. A simple device called an ET gauge also was installed along with a rain gauge. The local ET data from the ET gauge and GMD weather stations were in good agreement for the growing season. Scheduling based on ET helped producers to take advantage of rainfall to meet the crop's water need. The average corn yeild from the demonstration fields was 205 bu/a. Soil sensors helped in validating soil water status and making irrigation scheduling decisions. Irrigation scheduling for better irrigation management is the key to water conservation. An intensive educational effort is necessary to make the adoption of irrigation scheduling by farmers a reality. Spreadsheets and computer software are now available that make data retrieval faster and allow quick decisions.

INTRODUCTION
Irrigation scheduling means providing an appropriate quantity of water to the crop at the proper time to secure profitable production. Irrigation provides for consistent annual production of corn, grain sorghum, wheat, alfalfa, soybean, and sunflower in western Kansas. About 2 million acres in this region depend on the Ogallala aquifer, a confined system with very limited recharge. The water level is declining, and depletion of this nonrenewable reserve has become a major focus for economic sustainability. Introduction of center pivot irrigation systems has improved application uniformity, but irrigation scheduling and good management are required to achieve efficient water use. Various methods are available to make a decision on irrigation timing and to calculate the amount. Farmers have used the appearance of the crop to decide when to irrigate. However, by the time the visual symptoms become apparent, the crop already has suffered from stress, and the optimum production may have been affected. Evapotranspiration (ET)-based irrigation with appropriate soil-water monitoring is the most scientific method to implement irrigation scheduling.
Irrigation scheduling tools like soil-water sensors, ET data, and computer software to keep track of a water budget are available, yet field adoption of irrigation scheduling is limited. Unlike other agricultural inputs, irrigation necessitates continuous decision making during the entire crop season. Crop water demand, although varied in quantity, occurs throughout the growing season. Farmers in western Kansas tend to simplify the situation by turning on the pivot system and running it until the end of the season. This may be appropriate for irrigation wells with insufficient capacity. Long hot days with southwest dry winds make farmers fearful of falling behind in satisfying the crop demand. However, those who have high capacity wells, have the opportunity to shut down the irrigation system occasionally.
Crop water demand is low in the early growing season. The root system is less prolific and is drawing from the top layer of the reserve. Information on crop water use (ET), available soil water capacity, and root depth may help in deciding on when to irrigate and  how much to apply, especially at this time when the root zone is small. Most of the farmers hire consultants who guide them through the season. Consultants do not want to take risks with water application, because this is considered to be a relatively cheap input. They use a push type rod or regular soil probe to evaluate soil water from feel and appearance and tend to be conservative.
Kansas State University has launched an educational program, and County Extension Agents have set up demonstration sites to work one-on-one with owners/operators. According to the request of the owner of the demonstration field, agricultural consultants are involved in the program whenever possible. The goals are to educate producers in southwest Kansas and demonstrate the field application of ET-based irrigation scheduling.

PROCEDURES
Irrigation-scheduling demonstration fields planted to corn were set up in nine counties within southwest Kansas. The farmer operators agreed to keep irrigation application records and bulk yield data. Each demonstration site was equipped with soil-water sensors like gypsum blocks, Watermark sensors, and tensiometers. Three types of sensors were used to see which one suited the particular soil type. These were set up in two locations per field at three different depths. The choices for depths of placement in 1998 were 9, 18, and 30 inches below the soil surface.
Soil samples were taken periodically for gravimetric evaluation of soil water. Neutron access tubes were installed at two sites with different soil textures (Ulysses silt loam and Tivoli fine sand).
The ET data from the weather station at the Southwest Research-Extension Center were used to calculate water balance. Simple tools like atmometers (ET gauge) and rain gauges were set up to record ET and rainfall at each local site.
Southwest Kansas Groundwater Management District #3 has installed 12 new weather stations, which will make ET data available to local farmers. A sample of the spreadsheet that was used to track water balance using ET data, rainfall, and soil water status is shown in Table 1.

RESULTS AND DISCUSSION
This project was started in 1997. The plan in the first year was to record conditions without interfering with farmers' irrigation plans. This gave us the information to look for any opportunities to turn off the system occasionally. In 1998, a hot and dry spell occurred from mid June to mid July. Soil water in some fields fell below management allowable depletion levels. Fortunately, rain fell before the reproductive stage, and production did not suffer. Some fields with sandy soil showed some scorching in spite of good soil water conditions.
The reference ET data from ET gauges and Penman reference ET from Groundwater Management District (GMD) weather stations in the counties within District #3 are shown in Fig. 1. The cumulative ETs from both the sources are in good agreement for the growing season.
The ET gauge data for Farm No.1 and Farm No. 4 are compared to the data obtained from the weather station at the Southwest Research-Extension Center because of lack of data from GMD Stations. Soil water monitoring results for the gypsum block on Farm No. 5 are presented in Fig. 2. The dry weather period is reflected in the data set. The soil water tension rose to 9 bars between mid-June and mid-July. The irrigation system was able to catch up after rainfalls on July 9 (0.4 inch) and July 13 (1.1 inches). Tensiometer and Watermark sensors showed similar trends within the limits of their reading scales. Fig. 3 compares rainfall amount and irrigation applied to ET actual (ETa). It shows that the scheduling procedure helped the producers to take advantage of rainfall to meet the crop's water need. They were able to shut off the system when soil water was recharged.
The corn yield data for 1998 are shown in Fig: 4. The average yield for the demonstration plots was above 205 bu/a.
The ET data from the Southwest Research-Extension Center were posted manually on a web page in 1998. This will be automated in 1999, which will help producers to download the data automatically using the web browser. A spreadsheet has been developed to link data acquisition via the web browser from the web page. The producer or consultant can update the ET scheduling spreadsheet in the early morning. This will help make an irrigation decision quicker and easier.
The web address for the Kansas State University weather station at Garden City was: www.oznet.ksu.edu/wkarc/swrec/weather1.htm for 1998 and the website has been changed to http:// www.oznet.ksu.edu/wdl/wdl/et99b.htm for 1999.
The web address for Groundwater Management District weather stations is: www.ink.org/public/ksgm Irrigation field days were held at each site for educational purposes. A series of educational seminars and hands-on training on ET-based irrigation scheduling also were presented in cooperation with the Groundwater Management District #3. This effort will continue.

SUMMARY
Twenty-six corn hybrids (15 Bt-and 11 non-Btcorn) were evaluated for corn borer resistance and grain yield performance. The yield losses to girdling by southwestern corn borers averaged 30 bu/a for the unsprayed non-Bt hybrids, 2.9 bu/a for sprayed non-Bt hybrids, and 19.4 bu/a for hybrids with event 176. Hybrids with Bt11, MON810, and CBH351 had virtually no yield losses. A yield loss of 20.9 bu/a was associated with spider mite leaf damage. Grain yields averaged 187.9 bu/a across all hybrids in the sprayed block and 165.0 bu/a in the unsprayed block.

PROCEDURES
Corn plots were machine-planted on 13 May at 30,000 seeds/a at the Southwest Research-Extension Center near Garden City, KS. Spot replanting was done as necessary. Across hybrids, the number of plants with ears at harvest varied from 91 to 117 plants per 60 row-ft. Preplant herbicides applied on 10 April were 2 qt Milo-Pro, 1 qt 2,4-D and 1 pt Roundup/a. Postemergence herbicides applied on 2 June were 7 oz. Accent and 0.5 pt Banvel with 0.2 qt surfactant/a. The soil was a saline-Richfield silt-loam with a pH of 7.5 to 8.0. The field was furrow irrigated on 18 June, 2 July, 18 July, and 24 Aug. with 4.6, 4.1, 4.2, and 4.1 inches of water, respectively. Monthly rainfalls for April through Aug. were 0.9, 2.7, 0.9, 6.61, and 3.1 inches. The plots were four rows wide (10 ft) by 30 ft long. Two border rows (5 ft) of Bt corn were planted between the plots, and 10-ft alleyways at the end of each plot were left bare. The border rows and alleyways were included to reduce larval migration between plots. The experimental design was a split-plot with four replications. The main plots were insecticide-protected versus insecticide unprotected, and the sub-plots were the corn hybrids. The protected blocks were sprayed on 17 July with Capture (bifenthrin) at 0.08 lb. AI/a. We used 26 hybrids with relative maturity ratings of 110 to 118 days. An attempt was made to pair each non-Bt hybrid with its Bt sister line or with another related hybrid. Pioneer 3162IR was included as the standard commonly used hybrid.
On 22 and again on 29 June, 25 to 30 neonate European corn borers (ECB) were placed in the whorls of 10 plants in each plot to supplement the native first generation infestation. However, shot-hole damage was minimal, so no data were collected on first generation corn borers. In Sept., spider mite damage was evaluated by examining three leaves (the ear-leaf and the second leaf above and below it) on six plants in each plot. The percentage of each leaf having spider mite damage was recorded and averaged for each plot. Second generation corn borer infestations were entirely native. Data for second generation corn borers were taken from five consecutive plants in one of the two center rows of each plot. The plants were dissected to record corn borers and corn borer tunneling. Kernel damage was recorded as the estimated percentage of kernels damaged at the tip (mostly corn earworm) and at the base or side of the ear (mostly corn borer damage). In addition, lodged plants in the middle two rows were counted and separated into those girdled by southwestern corn borer (SWCB) and those that lodged from European corn borer tunneling or stalk rot. Yield was determined by separately harvesting ears from standing plants and from fallen plants. The lodged corn was harvested by hand, and the standing corn was machine harvested. The two middle rows of each plot were harvested in late October. Grain yield was calculated separately for standing and fallen corn and corrected to 15.5% moisture. The data were analyzed both as a two-factor experiment (including both sprayed and unsprayed plots) and as two single-factor experiments (sprayed and unsprayed plots analyzed separately). To simplify the discussion, results are averaged across the four Bt events and the sprayed and unsprayed non-Bt hybrids.
Spider mite pressure was high during the hot dry spell in August (Fig. 4). In the unsprayed block, spider mite leaf damage averaged 59.1%, and in the Capture-sprayed block, it averaged 27.1%. Capture is a good miticide that apparently was able to suppress the spider mite damage during the hot dry period in August. Across the Bt hybrids (with no corn borer damage), the yield difference between sprayed and unsprayed was 20.9 bu/a. This yield loss appeared to be associated with a 24% difference in spider mite leaf damage.
Corn earworm damage to kernels in the ear tip was relatively light, averaging only 1.5% in the unsprayed non-Bt (Tables 1 & 2). Hybrids with Bt11 and Mon810 averaged 51 and 30% reductions in kernel damage, respectively (Fig. 5). Hybrids with Bt176 or CBH351 and sprayed non-Bt hybrids had small reductions in kernel damage. Damage at the ear base was minor and did not differ significantly across the hybrids. Grain yields averaged 187.9 bu/a across all hybrids in the sprayed block and 165.0 bu/a in the unsprayed block (Tables 1 & 2, Fig. 6). The standard hybrid, Pioneer 3162IR, yielded 203.0 bu/a in the sprayed block, but only 159.1 bu/a in the unsprayed block. A number of Bt and non-Bt hybrids were among the top yielders.

Southwest Research-Extension Center
SUMMARY Treatment responses were very consistent across all locations. This test clearly showed the impact of injury to growing wheat from herbicide application in the fall in the absence of weed pressure. All treatments reduced yield at least 5 bu/a, with the exception of the applications of .023 lb/a picloram or 0.25 lb/a quinclorac. Except for treatments containing more than 0.375lb/a of dicamba, no treatment reduced yield more than 12 bu/a. These results should allow the producer to weigh the cost of crop injury against the future value of controlling bindweed. Prior work has shown that conventional applications applied 11 months before planting do not injure wheat and often provide better control than fall applications in growing wheat. Therefore, the loss of yield from fall herbicide applications can be avoided by timely planning a year prior to planting.

INTRODUCTION
Often when wheat prices are poor and cattle prices are high, producers will plant wheat early to increase fall forage production. This often will not allow the producer to properly apply bindweed control measures prior to planting wheat. In previous field day reports, fall application of bindweed-control treatments in growing wheat has been described as a modestly effective method to make the best of a poor situation. However, the studies could not separate the effects of the herbicide injury from the injury inflicted by the bindweed itself.
Therefore, these studies were initiated to measure the impact of the herbicide treatments in the absences of weeds to allow the producer to better judge what bindweed control method to use.

PROCEDURES
Wheat was planted as described in Table 1 in an area with little prior history of weed pressure. Continuous wheat was grown at the south Garden City location. All other locations were cropped to a fairly weed-free wheat-fallow-wheat rotation. Treatments were applied in the fall to growing wheat as described in Table 2. In all areas, weed pressure was very low throughout the test period.

RESULTS AND DISCUSSION
Although the magnitude of injury differed across the three locations, the relative degree of injury associated with each treatment did not, as evidenced by no statistically significant location by treatment interaction. The means of the individual locations are presented to show the consistency of responses across locations, but the reader need look only at the means averaged over the locations. All treatments containing dicamba caused some level of injury. This injury tended to increase with higher rates, from 16% at the lowest rate to 30% at the highest rate. All treatments but the 2,4-D reduced head number/foot of row. Only picloram/dicamba tank mixes reduced wheat height.
All treatments reduced yield at least 5 bu/a, with the exception of the applications of .023 lb/a picloram or 0.25 lb/a quinclorac. Except for treatments containing more than 0.375lb/a of dicamba, no treatment reduced yield more than 12 bu/a.
Previous work has shown that in a wheat-fallowwheat rotation, no yield loss is seen from bindweedcontrol treatments applied 11 months prior to planting. Also, control from these treatments is often superior to that from applications made in growing wheat in the fall. However, none of the treatments applied in

IMPACT OF FALL-APPLIED HERBICIDES FOR BINDWEED CONTROL IN WEED-FREE WHEAT
by Randall Currie this study caused greater than a 15 bu yield loss on average. In some situations, this yield loss may not be excessive; for example, spot spraying less than  10% of a field of wheat that is to be saved for seed or as part of an aggressive bindweed control program on land that will be planted to seed wheat in the future. Note: Moisture of wheat adjusted to 12.5% to determine bu/a.

SUMMARY
All herbicides provided good control at some rate in some years. However, herbicides varied greatly in consistency from year to year. In general, variability in control declined and overall control increased with increasing rates. Only quinclorac at 1 lb/a, glyphosate at 4 lb/a, and picloram at 0.25 lb/a or greater provided better than 93.5% control in all years. Quinclorac at 0.125 lb/a provided 81.8 to 95.7% control in all years. Dicamba at rates higher than 0.5 lb/a provided 72.8 to 100% control in all years. Although the averages across years are presented, these numbers should be used with great care.

INTRODUCTION
Fall-applied herbicide treatments are often very effective across a broad range of perennial weeds. Bindweed control, regardless of herbicide treatment, is often difficult to predict. However, in general, as the herbicide rate goes up, the efficacy and consistency of the treatment increase. Therefore, the objective of this study was to compare several herbicides at a broad range of rates to determine the rate of diminishing returns for each herbicide and to allow head-to-head comparisons of these herbicides at rates that produce similar levels of control.

PROCEDURES
Herbicide treatments were applied the fall after wheat harvest in a wheat-fallow-wheat rotation as described in Table 1. Bindweed control was measured in the following spring by calculating percent reduction in shoot length times shoot number per square foot.

RESULTS AND DISCUSSION
All herbicides provided good control at some rates in some years. However, herbicides varied greatly in consistency from year to year. In general, variability in control declined and overall control increased with increasing rates. Only quinclorac at 1 lb/a, glyphosate at 4 lb/a, and picloram at 0.25 lb/a or greater provided better than 93.5% control in all years. Quinclorac at 0.125 lb/a provided 81.8 to 95.7% control in all years. Dicamba at rates higher than 0.5 lb/a provided 72.8 to 100% control in all years. Although the averages across years are presented, these numbers should be used with great care. Because of losses to wildlife in 1998 in two or more of the replicates, only 2 years of data were used for the 0.25 and 0.5 lb/a quinclorac treatments.
Much yet needs to be learned about how climate affects these herbicides. The 1 lb/a rate of 2,4-D or glyphosate performed well in only 1 out of 3 years. Therefore, a producer should base his bindweed control choices on much more than one experience.

SUMMARY
Although time of application occasionally appeared to have an effect for most herbicides tested, this effect was not consistent across years. Regardless of time of application or tank-mix partner, picloram provided excellent woollyleaf bursage control. All other tank mixes provided poor or inconsistent control. The additon of dicamba to various tank mixes did not increase preformance more than the addition of 2,4-D.

INTRODUCTION
Woollyleaf bursage, also known as bur ragweed, is a noxious perennial weed infesting more than 80,000 acres in southwest Kansas. It is found most frequently in low-lying areas of fields but also in the higher areas because of movement of rootstocks and seeds by tillage equipment. Once established, this weed is very difficult to control. The objective of this study was to compare control of woollyleaf bursage by several herbicides applied at flowering and 30 days later.

PROCEDURES
The study was established in August, 1990August, , and replicated in the 1994August, , 1995August, , and 1997 growing seasons. The experimental design was a two-factorial randomized complete block with two levels of application timing, nine levels of herbicide treatment, and three replications (Tables 1 and 2). Herbicides were applied with a CO 2 -pressurized, hand-held sprayer equipped with a six-nozzle boom. Application volume was 20 gal/a. Herbicides were applied at flowering on August 15 and on September 15.
Both treatments were evaluated for woollyleaf bursage control 9 and 11 months later. The percent weed control was calculated by dividing the number of stems per unit area in the treated plots by the number in the corresponding control plot, subtracting this from 1, and multiplying the difference by 100.

RESULTS AND DISCUSSION
Although a rate response was seen in clopyralid treatments, some level higher than 0.25 lb/a may be necessary to provide control. The more ecomomical 2,4-D tank-mix partner performed as well as dicamba with fluroxypr, picloram, or glyphosate. All tank mixes of picloram consistently provided over 93% control in all years, regardless of time of application. All other tank mixes provided poor or inconsistent control. In 10 out of 12 tank-mix timing combinations over 3 years, less than 60% control was achieved with tank mixes containing 1.5 lb/a of glyphosate. Although glyphosate clearly has activity on woollyleaf bursage, a weed shift to this species might be expected if competition from other weeds is removed by continuous applications of conventional 0.5 to 1.5 lb/ a rates of glyphosate.

SUMMARY
When grain prices are low, producers more often consider wheat or other small grain cereal crops for winter pasturing in addition to harvesting for grain. This forage clipping comparison showed that wheat produced an average of 715 lb/a of dry matter, triticale an average of 702 lb/a of dry matter, and rye an average of 998 lb/a of dry matter prior to being allowed to mature for grain harvest. All three crops ultimately produced grain yields of about 80 bu/a.

INTRODUCTION
The production and use of small grain forages can be useful to producers based on the relative net returns of forage versus grain. Small grain cereals can be pastured until the jointing stage in early spring and then still produce a grain crop. This study was designed to address relative winter forage production as well as grain yields of some cereal grains that might be considered for dual-purpose use.

PROCEDURES
Ten varieties of wheat, triticale, and rye were seeded on October 16, 1997. Two Kansas wheats were included along with triticale and rye entries of Polish origin. The study was a randomized complete block design with four replications. Forage was collected by hand clipping at 1 inch above the soil surface, and data are shown as lb/a of oven-dried forage. Grain was harvested on June 30, 1998.

RESULTS AND DISCUSSION
Rye displayed its usual ability to produce higher forage yields during cold weather than other winter small grains. The forage yields of wheat and triticale were about 75% of rye forage yields. Results are shown in Table 1. All grain yields were similar, except that of Fidelio triticale. Fidelio was short statured, late maturing, and significantly lower yielding than other entries. Final grain-yield averages were 4615 lb/a, (77 bu/a at 60 lb/bu) for wheat, 4236 lb/a (85 bu/a at 50 lb/bu) for triticale, and 4692 lb/a (84 bu/a at 56 lb/bu) for rye.

INTRODUCTION
In an effort to increase yield potential, researchers are looking at row spacings that are narrower than the traditional 30 inches. Corn grown in closer rows more quickly shades the ground, because light energy is intercepted more completely by the crop early in the season. This increased crop utilization of earlyseason sunlight has increased corn yields as much as 10% in studies in some of the northern cornbelt states.

PROCEDURE
Four hybrids, Cargill 8021 Bt, Golden Harvest 2530 Bt, Northrup King 7590 Bt, and Pioneer 33A14 Bt were planted on May 12, 1998 in replicated splitplot design. Resulting stands were equalized at emergence by removal of excess plants in the 15-inch row treatments to provide populations of 30,000 plants/ a for both row spacings. Plots were irrigated three times during the summer and kept weed-free with Prowl/Bladex herbicide. On October 5, 1998, 25foot lengths of the center two rows of four-row plots were harvested for 30-inch row treatments, and 25foot lengths of the center four rows of eight-row plots were harvested for 15-inch row treatments.

RESULTS AND DISCUSSION
Grain yields of these corn hybrids increased about 5% (12 bu/a) from use of narrow 15-inch row spacing as compared to the more traditional 30-inch row spacing. Yields are presented in Table 1. An important consideration is that equipment to plant and harvest narrow rows is required to take advantage of this 5% yield enhancement.

INTRODUCTION
Canola is a new type of oilseed rape. It differs from traditional industrial rape in having a muchreduced amount of erucic acid and a lowered level of glucosinolates. Because of these changes, it can provide both a healthful cooking oil and a highquality protein meal supplement for livestock.

PROCEDURES
Twenty-four varieties and experimental lines were planted on September 5, 1997 at 9 lb seed/a in randomized complete block plots. Plots were combine harvested on June 25, 1998 by removing the reel to reduce shattering losses.

RESULTS AND DISCUSSION
Yields from 1998 on a dryland field are shown in Table 1. Excellent winter survival occurred in 1997-1998 such that yields ranging from 464 lb/a to 1280 lb/a were produced. However, in 1996-1997, stand survival following winter losses ranged from 0% to 58% depending upon variety. In 1995-1996, stand survival following winter losses ranged from 0% to 52% depending upon variety. At present, the most important factor in considering a canola variety to grow in Kansas is winter survival.