Kansas Fertilizer Research 2004

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Introduction
Fertilizer companies continue to evaluate different products and processing technology for producing crop nutrients. Studies were established in Ellis County in western Kansas and Saline County in central Kansas to evaluate several P fertilizer products being evaluated by Cargill.

Procedures
Soil tests for these locations are presented below. Broadcast/incorporated N, NP, or NPS applications (rates below) were made on September 23, 2003 and wheat planted within the next two weeks. Both locations were topdressed (N rates of 50 and 80 lbs N/A at Ellis and Saline County, respectively) in late February 2004.

It was a difficult year for wheat in parts of
Kansas this year, with drought conditions and late freeze in the western part of the state severely limiting yields. In addition, persistent wet weather in June early July hampered wheat harvest across the state, with sprouting causing problems in local areas across the state.
The Ellis County location provided yields of about 15-20 bu/a with no response to applied P fertilizer. Saline County provided response to P application and some differences among P products. Tissue and grain P analysis data are presented along with grain yield data from the two locations in Tables 2 and 3.

Introduction
Limited research has focused on using chloride fertilizers to increase smooth bromegrass production. For wheat and some other cereal grains, chloride (Cl) has been reported to have an effect on plant diseases, either suppressing the disease organism or allowing the plant to be able to withstand infection. The objective of these studies were to evaluate the effects of Cl fertilization on forage yields of smooth bromegrass in Kansas.

Procedures
Three field sites in Kansas were identified that had a history of brome production. Sites were located in Riley County, Pottawatomie County, and Osage County. Treatments consisted of three chloride rates (0, 10, 20 lb Cl/a) and two chloride sources (KCl, NH 4 Cl). All treatments were balanced at 90 lb N/a. Treatments were replicated four times in a randomized complete-block design. Treatments were applied in late February 2004 and plots were harvested on May 25, 2004. Yields were determined by harvesting a 30-in. section of each plot and weighing the biomass. A sub-sample from each plot was collected and dried to determine moisture content. Samples were then ground and analyzed for plant nitrogen and chloride concentration.

Results
Results from this study are presented in Tables 1 and 2. Chloride concentration in soil samples collected from each site indicated that the Osage County site was the only site that tested medium to low for chloride concentration (#6 ppm).
On average, chloride concentration in tissue increased with increasing rates of chloride at all sites. However, nitrogen percentage in tissue was not effected by chloride fertilization. Forage yield was increased at Osage County with the application of 20 lb Cl/a as NH 4 Cl, compared with the control. In addition, 10 lb Cl/a as KCl increased forage yield, compared with that of the control at Osage County. The results of this study indicate a yield response may be observed if chloride fertilizer is applied to bromegrass on low-testing chloride soils (6 ppm or below). This study will be continued in 2005. lb/a --------------------lb/a --------------------0 ---  Soil Test Cl, ppm 11 9 6 Nitrogen balanced at 90 lb/a on all treatments

A.J. Schlegel
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 2004, N and P applied alone increased yields about 95 and 30 bu/a, respectively; however, N and P applied together increased yields up to 173 bu/a. Averaged across the past 10 years, corn yields were increased more than 100 bu/a by N and P fertilization. Application of

Introduction
This study was initiated in 1961 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 content remained high so the K treatment was discontinued in 1992 and replaced with a higher P rate.

Procedures
Initial fertilizer treatments in 1961 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 were changed, with the K variable being replaced by a higher rate of P (80 lb P 2 O 5 /a).
Hail damaged the 2002 crop and destroyed the 1999 crop. The corn was irrigated to minimize water stress. Furrow irrigation was used through 2000, and sprinkler irrigation has been used since 2001. The center 2 rows of each plot were machine harvested after physiological maturity. Grain yields were adjusted to 15.5% moisture.

A.J. Schlegel
Summary Long-term research shows that phosphorus (P) and nitrogen (N) fertilizer must be applied to optimize production of irrigated grain sorghum in western Kansas. In 2003, N and P applied alone increased yields about 50 and 13 bu/a, respectively; however, N and P applied together increased yields more than 65 bu/a. Averaged across the past 10 years, sorghum yields were increased more than 50 bu/a by N and P fertilization. Application of 40 lb N/a (with P) was sufficient to produce >90% of maximum yield in 2003 and for the 10-year average. Application of K had no effect on sorghum yield in 2003 or averaged across all years.

Introduction
This study was initiated in 1961 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 2001.

Procedures
Fertilizer treatments initiated in 1961 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. All fertilizers were broadcast by hand in the spring and incorporated before planting. The soil is a Ulysses silt loam.
Sorghum (Mycogen TE Y-75 from 1992-1996, Pioneer 8414 in 1997, and Pioneer 8500/8505 from 1998-2003 was planted in late May or early June. Irrigation was used to minimize water stress. Furrow irrigation was used through 2000, and sprinkler irrigation has been used since 2001. The center 2 rows of each plot were machine harvested after physiological maturity.
Grain yields were adjusted to 12.5% moisture.

Results
Grain sorghum yields in 2003 were higher than the 10-year average (Table 1). Nitrogen alone increased yields up to 51 bu/a, whereas P alone increased yields 13 bu/a. Nitrogen and P applied together increased sorghum yields more than 65 bu/a. Only 40 lb N/a was required to obtain >90% of maximum yields which was consistent with the 10-year average. Sorghum yields were not affected by K fertilization, which has been true throughout the study period.

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 (effluent water from a lagoon) and cattle (solid manure from a beef feedlot) wastes have been applied annually since 1999 at rates to meet estimated corn P or N requirements, along with a rate double the N requirement. Other treatments were nitrogen (N) fertilizer (60, 120, and 180 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 w as initiated in 1999 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 1). The Kansas Dept. 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 105 lb P 2 O 5 /a because soil test P levels were less than 150 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 2001 and 2002 were great enough to eliminate the need for additional N. So no swine effluent was applied to the 1xN treatment in 2002 or 2003 or to the 2xN requirement treatment, because it is based on 1x treatment (Table 1). 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 17.5 lb available N and 25.6 lb available P 2 O 5 per ton of cattle manure and 6.1 lb available N and 1.4 lb available P 2 O 5 per 1000 gallon of swine effluent (actual analysis of animal wastes as applied differed somewhat from the estimated values, Table  2). Subsequent applications were based on previous analyses. Other nutrient treatments were three rates of N fertilizer (60, 120, and 180 lb N/a), along with an untreated control. The experimental design was a randomized complete block with four replications. Plot size was 12 rows wide by 45 ft long.
The study was established in border basins to facilitate effluent application and flood irrigation. The swine effluent was floodapplied 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 10-ft fertilizer applicator (Rogers Mfg.). The entire study area was uniformly irrigated during the growing season with flood irrigation in 1999 through 2000 and sprinkler irrigation in 2001 through 2004. 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 1999 because of severe hail damage. Hail also damaged the 2002 crop. The center four rows of each plot were machine harvested after physiological maturity, with yields adjusted to 15.5% moisture.

Results
Corn yields were increased by all animalwaste and N-fertilizer applications in 2004, as has been true for all years except 2002, in which yields were greatly reduced by hail damage (Table 3). The type of animal waste affected yields in 3 of the 5 years, with higher yields from cattle manure than from swine effluent. Averaged across the 5 yr, corn yields were 14 bu/a greater after application of cattle manure than swine effluent on an Napplication basis. Over application (2xN) of cattle manure has had no negative impact on grain yield in any year. However, overapplication of swine effluent reduced yields in 2004 because of considerably greater salt content (2-3 times greater electrical conductivity than any previous year), causing germination damage and poor stands.

Summary
During a 20-year grain sorghum-soybean rotation, grain sorghum yields were generally greater with conventional or reduced tillage than with no tillage and with N fertilization, especially as anhydrous NH 3 . In contrast, during the 20 years, soybean yield was unaffected by tillage or residual N. At the end of the 20-year study, tillage options resulted in distribution differences of soil organic-matter content in the top six inches, but no overall difference in concentration. Soil bulk density at the end of 20 years was unaffected by tillage or N fertilization choices.

Introduction
Many rotational systems are employed in southeastern Kansas. This experiment was designed to determine the long-term effect of selected tillage and nitrogen (N) fertilization options on the yields of grain sorghum and soybean in rotation.

Procedures
A split-plot design with four replications was initiated in 1983, with tillage system as the whole plot and N treatment as the subplot. The three tillage systems were conventional, reduced, and no tillage. The conventional system consisted of chiseling, disking, and field cultivation. The reducedtillage system consisted of disking and field cultivation. Glyphosate (Roundup®) was applied each year at 1.5 qt/a to the no-till areas. The four N treatments for the oddyear grain sorghum crops from 1983 to 2001 were: a) no N (check), b) anhydrous ammonia knifed to a depth of 6 in., c) broadcast urea-ammonium nitrate (UAN -28% N) solution, and d) broadcast solid urea.
The N rate was 125 lb/a. Harvests were collected from each subplot for both grain sorghum (odd years) and soybean (even years) crops. Effects of residual N were measured for soybean, even though N fertilizer was applied only to grain sorghum. Soil samples were collected at the end of the 20-year study and were analyzed for bulk density and organic-matter content.

Results
Analyzed across all grain sorghum years (odd-numbered years) from 1983 to 2001, yield was affected by tillage and nitrogen fertilization ( Figure 1). Without N fertilizer, grain sorghum averaged approximately 40 bu/a in conventional and reduced tillage systems and around 30 bu/a in no-tillage. Anhydrous NH 3 application generally increased yields more than the other nitrogen fertilizers, except for broadcast urea in the reduced-tillage system. Although anhydrous NH 3 application improved yields in no-till, yields were still less than with anhydrous NH 3 applications in the other tillage systems. Grain sorghum yields were only statistically less with no-tillage in 5 of the 10 grain sorghum years (individual year data not shown). In those years, however, grain sorghum yield averaged 21 and 25 bu/a less with no-tillage than with reduced or conventional tillage, respectively. In contrast, analyzed across all soybean years (evennumbered years) from 1984 to 2002, soybean yield averaged 22.2 bu/a and was unaffected by tillage system or N residual (data not shown), even though growing conditions varied widely during this time, with soybean yields ranging from near 5 bu/a to more than 40 bu/a. Long-term continuous use of different tillage systems and N fertilization schemes has the potential to affect soil quality. Two of the measures of soil quality are organicmatter content and bulk density.
Soil organic-matter content in the 0-to 3-inch zone was less with conventional tillage than with either reduced or no-tillage (Table 1). In the 3-to 6-inch zone, however, organicmatter content was less with no tillage than with conventional or reduced tillage. As a result, when composited across the 0-to 6inch zone, which is the typical soil-sampling depth, organic matter was not statistically affected by tillage. These data show that distribution of organic matter may change in the top 6-inch soil zone, but that the overall concentration is not affected by tillage.
Organic-matter content in the 6-to12-inch zone was also not affected by tillage. Nitrogen fertilization schemes also did not affect organic-matter content at any soil depth. Bulk density was not affected after twenty years by tillage system or N fertilization scheme at any soil depth (Table  2). In this claypan soil, soil quality, as indicated by organic-matter content and bulk density, was not greatly affected by twenty years of different tillage systems or N fertilization schemes.  Organic Matter Treatment 0-3" 3-6" 0-6" 6-12" Bulk Density Treatment 0-3" 3-6" 0-6" 6-12"

Introduction
The response of soybean to phosphorus (P) and potassium (K) fertilization can be sporadic, and producers often omit these fertilizers. As a result, soil test values can decline. Acreage planted with no tillage may increase because of new management options such as glyphosate-tolerant soybean cultivars. But data are lacking about the importance of soil P and K concentrations on yield of glyphosate-tolerant soybean grown with no tillage.

Procedures
The experiment was established on a Parsons silt loam in spring 1999. Since 1983, fertilizer applications have been maintained to develop a range of soil P and K concentrations. The experimental design is a factorial arrangement of a randomized complete block, with three replications. The three residual soil P amounts averaged 5, 11, and 28 ppm, and the three soil K amounts averaged 52, 85, and 157 ppm at the conclusion of the previous experiment. Each year, Roundup Ready® soybean was planted during late May to mid June with no tillage.

Results
Environmental conditions in 2003 resulted in soybean yields averaging about 20 bu/a (Table 1). Soil P concentrations had no effect on soybean yields.
But an increased number of pods per plant with the greatest soil test P may suggest a potential for increased yield under better growing conditions.
Greater soil K amounts increased glyphosate-tolerant soybean yield by as much as 21%, compared with plots that have never received K fertilizer. This yield increase may have been related to changes in pods per plant and seeds per pod. Yield was affected by a P x K interaction in which an increase in soil K resulted in a yield increase in the absence of P fertilization or with greater amounts of P fertilization, but not in soil that had received lesser amounts of P fertilization.

Summary
Tillage selection did not significantly affect short-season corn yields in 2003. Early-spring fertilization with N and P solutions resulted in greater yield than did N-P fertilizer application in late fall.

Introduction
The use of conservation-tillage systems is promoted to reduce the potential for sediment and nutrient losses. In the claypan soils of southeastern Kansas, crops grown with no tillage may yield less than those grown in systems involving some tillage operation. But strip tillage provides a tilled seed-bed zone where early-spring soil temperatures might be greater, while leaving residues intact between the rows as a conservation measure similar to no tillage.

Procedures
The experiment was established on a Parsons silt loam in late fall 2002. The experimental design was a split-plot arrangement of a randomized complete block, with three replications. The four tillage systems constituting the whole plots were: 1) strip tillage in late fall, 2) strip tillage in early spring, 3) reduced tillage (1 pass with tandem disk in late fall and 1 pass in early spring), and 4) no tillage. The subplots were a 2×2 factorial arrangement of fertilizer timing and fertilizer placement.

Introduction
The quality of our water resources is an important topic. Agricultural practices are perceived to impact surface water quality by being a non-point source of pollutants. Producers need to use voluntary practices, such as Best Management Practices (BMP), to protect and improve surface water quality in the state. Recent state-wide efforts in Kansas are designed to look at large, fieldscale integrations of BMP to determine their effects on losses of sediment, nutrients, and pesticides into surface waters.

Procedures
The experiment was established on a Parsons silt loam in spring 1999 at the Greenbush Facility in Crawford County, but was not fully implemented until 2000. The four treatments were: 1) Conventional tillage (spring chisel, disk, field cultivate, plant); Low management: nitrogen (N) and phosphorus (P) broadcast, with incorporation by tillage; and atrazine and metolachlor herbicides applied preemergence, 2) Conventional tillage; High management: N and P knifed in, followed by tillage; metolachlor applied preemergence and atrazine applied post-emergence, 3) No tillage; Low management: N and P broadcast; atrazine and metolachlor applied preemergence, and 4) No tillage; High management: N and P knifed in; metolachlor applied preemergence and atrazine applied postemergence. For grain sorghum, the total N rate was 120 lb/a and P was 40 lb P 2 O 5 /a. The background crop in 1999 was soybean. Grain sorghum was planted in 2000, 2001, and 2003, and soybean was planted in 2002. At the downslope end of each 1-acre plot, a soil berm was constructed to divert surface water flow through a weir. In March 2001, soil berms were planted with fescue grass and covered with erosion matting material to minimize the potential for berm erosion to affect sediment values from runoff samples, as it seemed had occurred in 2000. Each weir was equipped with an ISCO ® sampler that recorded flow amounts and collected runoff samples.
Water samples were analyzed at the Soil Testing Laboratory for sediment, nutrients, and selected herbicides.

Results
Runoff and loading rates during 2001 to 2003 have been variable (Table 1). No tillage with high management (NTH) often resulted in greater runoff and total losses of potential pollutants, although the differences are not always significant. Regardless, measured sediment, nutrient, and pesticide loadings (Table 1) and concentrations (Table  2) from all treatments generally seem small.   2.9a 2.5a 5.5a 13.0a † CHL = conventional tillage with low management, CHH = conventional tillage with high management, NTL = no tillage with low management, NTH = no tillage with high management.
‡ Values within a column followed by the same letter are not significantly different at P=0.20.

Summary
In 2004, corn yields were increased by top dressing nitrogen. Nitrogen rates were applied to corn that received 120 lbs N as anhydrous before planting. Nitrogen, side dressed at 45 or 60 lbs/a, increased yields by 10 bu/a over plots not side dressed.

Many corn producers in Southeastern
Kansas apply all their nitrogen on corn ground before planting. Most years, in the spring, the claypan soils become saturated, and denitrification can occur. This study was designed to determine if top dressing nitrogen to the growing crop improves yields.

Procedures
Study was conducted on a Parsons silt loam that is an upland, claypan soil on a farm north of McCune in Crawford County.
Before planting, anhydrous ammonia fertilizer was applied at the rate of 120 lbs N/a.
Phosphorus and potassium were applied and incorporated. When the corn was 10 to 12 inches tall, nitrogen as urea was applied at: 0, 15, 30, 45, and 60 lbs/a was broadcast over soil surface. A 30 lb/a rate was also applied directly along side of the row to see if placement affected production.
The short-season Pioneer 35P12 hybrid was planted April 2, 2004, at kernel drop of 24,000/a. Nitrogen was broadcast May 6, when corn was 10 to 12 inches tall.

was a wonderful corn year.
Adequate and timely rainfall resulted in high corn yields. Long-time average yields for short-season corn is 88 bu/a. Yields in the test plots ranged from 129 to 139 bu/a (Table  1). Nitrogen top-dress applications of 45 or 60 lbs/a resulted in yields of 139.0 and 135.3 bu respectively. The two 30-lb N applications resulted in yields being significantly higher when the nitrogen was sidedressed along the row and not broadcast over the entire surface. Yields were 131.4 and 127.2, respectively.
Did it "pay" to top dress corn? Forty-five lbs of N at $0.32/lb = $14.40/a plus application cost. Yield response of 10 bu/a at $1.80/bu = $18.00. It depends on yield response, corn price, and of course, fertilizer cost.
Using anhydrous ammonia to sidedress would significantly reduce N cost.

Summary
Winter wheat was grown in rotation with grain sorghum in three no-till cropping systems, two of which included either a latematuring Roundup Ready® soybean or a sunn hemp cover crop established following wheat harvest in 2002. Nitrogen (N) fertilizer was applied for each grain crop at rates of 0, 30, 60, and 90 lb/a. Residual effects of soybeans on wheat were comparable to those of sunn hemp. At low N rates, wheat grew taller in systems with cover crops than where no legume had been grown. Increases in plant N attributed to cover crops ranged from 0.2% N to 0.27% N when N rates of 30 and 60 lb/a were applied. Differences in wheat N concentration among the cropping systems tended to disappear at the 90 lb/a N rate. Wheat yield increases of 5 to 9 bu/a from cover crops occurred at N rates of 0 and 30 lb/a, but higher N rates resulted in no significant differences in wheat production among cropping systems. Grain test weight and protein content were not affected by cover crop, but test weights tended to decrease somewhat with increasing N rate. Protein content increased only at the 90 lb/a N rate.

Introduction
Cover-crop research at the KSU Harvey County Experiment Field in the past has focused on the use of hairy vetch as a winter crop following wheat in a winter wheat-grain sorghum rotation. Results of long-term experiments showed that, between September and May, hairy vetch can produce a large amount of dry matter with an N content on the order of 100 lb/a. But significant disadvantages also exist in the use of hairy vetch as a cover crop. These include the cost and availability of seed, interference with the control of volunteer wheat and winter annual weeds, and the possibility of hairy vetch becoming a weed in wheat after sorghum.
In 2002, an existing experiment was modified to include late-maturing soybean and sunn hemp, a tropical legume, in lieu of hairy vetch. These summer cover crops were grown from early July through mid-October following wheat harvest, and produced an average of 3.91 and 3.52 ton/a of above-ground dry matter. Corresponding N yields of 146 and119 lb/a were potentially available to the succeeding grain sorghum crop. It was subsequently observed that when averaged across N fertilizer rates, soybean and sunn hemp significantly increased sorghum leaf nutrient content by 0.24% N and 0.29% N.
Sunn hemp increased grain sorghum yields by 10.6 bu/a, whereas soybean did not significantly benefit sorghum under existing conditions. In 2004, the residual effects of these cover crops, as well as those of fertilizer N, were determined in no-till winter wheat planted shortly after sorghum harvest.

Procedures
The experiment was established on a Geary silt loam site that had been used for hairy vetch cover-crop research in a wheatsorghum rotation from 1995 to 2001. In keeping with the previous experimental design, soybean and sunn hemp were assigned to plots where vetch had been grown, and the remaining plots retained the no-cover crop treatment. The existing factorial arrangement of N rates on each cropping system also was retained.
After wheat harvest in 2002, weeds were controlled with Roundup Ultra Max® herbicide. Hartz H8001 Roundup Ready® soybean and sunn hemp seed were treated with respective rhizobium inoculants and notill planted in 8-inch rows with a CrustBuster stubble drill on July 5 at 59 lb/a and 10 lb/a, respectively. Sunn hemp began flowering in late September and was terminated at that time by a combination of rolling with a roller harrow and application of 26 oz/a of Roundup Ultra Max®. Soybeans were rolled after initial frost in mid October. Forage yield of each cover crop was determined by harvesting a 3.28-feet 2 area in each plot just before termination. Samples were subsequently analyzed for N content.
Weeds were controlled during the fallow period and row crop season with Roundup Ultra Max®, atrazine, and Dual II Magnum®. Pioneer 8505 grain sorghum treated with Concept® safener and Gaucho® insecticide was planted at approximately 42,000 seeds/a on June 12, 2003.
All plots received 37 lb/a of P 2 O 5 banded as 0-46-0 at sorghum planting. Nitrogen fertilizer treatments were applied as 28-0-0 injected at 10 inches from the row on July 9. Grain sorghum was combine harvested on October 24, 2003. N rates were reapplied as broadcast 34-0-0 on October 28, 2003. Jagger winter wheat was then no-till planted at 90 lb/a with 35 lb/a P 2 O 5 fertilizer banded as 0-46-0 in the furrow.

Results
Early summer rains were sufficient to facilitate good stand establishment by soybean and sunn hemp cover crops. Despite below-normal July and August rainfall in 2002, both crops developed well. Late-maturing soybean reached an average height of 35 inches, showed limited pod development, and produced 3.91 ton/a of above-ground dry matter with an N content of 1.86%, or 146 lb/a (Table 1). Sunn hemp averaged 82 inches in height and produced 3.52 ton/a dry matter with 1.71% N, or 119 lb/a of N. It was noted that sunn hemp roots had little or no nodulation, evidence that the inoculant was ineffective. Soybean and sunn hemp effectively suppressed volunteer wheat and, in the fall, reduced the density of henbit, in comparison with areas having no cover crop.
Grain sorghum planted in mid-June suffered extreme drouth stress during the summer of 2003. Cover crops shortened the period from sorghum planting to half bloom by an average of two days and increased leaf N concentration across N rates by 0.24% to 0.29% N. Sunn hemp increased grain sorghum yields by 10.6 bu/a, whereas soybean did not significantly benefit sorghum under existing conditions.
Winter wheat responded to prior cover crops with increases in plant heights on the order of 2 to 3 inches at zero fertilizer N. This effect diminished or disappeared at N rates of 60 or 90 lb/a. When averaged over fertilizer rates, an increase of 0.12% plant N in wheat at early heading was noted as a positive residual effect of both cover crops. At low N rates of 30 and 60 lb/a, the increases in plant N attributed to cover crops were larger, ranging from 0.2% N to 0.27% N. Wheat N concentration differences among cropping systems tended to disappear only at the 90 lb/a N rate. The main effect of cover crops on wheat yield was significant, with increases of 4 bu/a from soybeans and 2.3 bu/a from sunn hemp. This was attributable to yield increases of 5 to 9 bu/a from cover crops at N rates of 0 and 30 lb/a. Higher N rates resulted in no significant differences in wheat yield among cropping systems. Grain test weight was not significantly affected by cover crops, but tended to decrease with increasing fertilizer N as a dilution effect associated with higher grain yields. Grain protein also was not significantly affected by prior cover crops. A 1.4% grain protein increase occurred only at the 90 lb/a N rate.

Summary
A potassium study was initiated on a field with presumed potassium deficiency. This study included K application rates of 0, 40, 80, and 120 lbs K 2 O/a and was conducted in Atchison county, Kansas. All fertilizer was broadcast applied. Extreme K deficiency was observed across most of the field, except at the far west end of the affected field. Discussion with the seed dealer prior to study establishment indicated that the intended hybrid was a 'K responsive, western hybrid'. Additional discussions with the farmer indicated that he had planted a different hybrid in two of the eight replications on the western end of the field. The seed dealer indicated that this hybrid was a more 'K non-responsive hybrid'. Significant and large grain-yield and test-weight advantages were associated with K application to the 'K responsive' hybrid, but no response was noted on the 'K non-responsive' hybrid.

Introduction
Potassium deficiency in row crops has become much more common in the western corn belt over the past decade. The increased K deficiency is most often associated with no-till/ridge-till production, but has also been reported in minimum tillage systems. Often, traditional soil testing programs have not indicated a need for applied potassium because soil tests are often in a 'sufficient' range.
This study is part of a larger project to improve corn and grain sorghum crop nutrient recommendations. A follow-up to this study is planned in the 2005 crop year.

Procedures
Soil samples from the 0-to 6-inch depth were collected from individual plots of the study. Soil test values ranged from 112 to 229 ppm exchangeable K. These soil tests would not have been expected to result in the severe potassium-deficiency symptoms observed at this site. This study was located in a farmer field that had a history of production problems.
Potassium rates of 0, 40, 80, and 120 lbs K 2 O/a were preplant broadcast applied in late winter. The applied K was incorporated on half of the plots and unincorporated in the other half. The treatments were replicated eight times across the field.
Most of the plot area (six replications) was planted to what the seed dealer referred to as a 'K responsive' hybrid, whereas the farmer planted a different 'non-responsive' hybrid on the two remaining replications. Two replications were lost to severe weed infestation. Grain yields were obtained by hand harvesting 20 feet of row from the center of each plot.

Yields
were not affected by incorporation of the K fertilizer, so tillage treatments were combined for analysis. A large yield response was measured with the hybrid referred to as a 'responsive' hybrid, whereas little if any response resulted in the non-responsive hybrid. This points to the fact that at least some seed sellers have hybrid-specific information that may be useful for making management decisions. In addition to grain-yield response, tests weights also benefitted from K application.

Summary
A series of corn and grain sorghum studies have been initiated across the state over the past two years to help refine the information needed for crop nutrient recommendations. These studies were conducted for corn and included P rates of 0, 20, 40, 80, and 120 lbs P 2 O 5 /a and were conducted at three locations across the state. All fertilizer was broadcast applied. Significant, large yield responses were obtained at two of the locations. In addition, the P and K content of the grain increased with increasing P rate, whereas the grain moisture content decreased.

Introduction
Several corn and grain sorghum studies have been initiated across the state to improve crop nutrient P and K recommendations. To meet this objective, the following information is being gathered from various studies conducted across the state of Kansas; 1) crop response to various rates of P and/or K application at various soil test values, 2) percentage sufficiency (for maximum yield) at various soil test values, 3) amounts of P and K nutrient application/crop removal to change soil test values, and 4) amounts of P and K removed in the harvested grain.
This project was initiated for the 2003 crop and will continue for the 2005 crop year.

Procedures
Soil samples from the 0-to 6-inch depth were collected from individual plots at some locations and from individual replications at others. Bray P1, Mehlich 3 colorimetric, and Mehlich 3 ICP soil test procedures were run on individual samples. For this report, only the Bray P1 results will be presented.
The Greeley County study was located on the K-State research station; the Republic and Stevens County studies were located in farmer/cooperator fields. All locations were sprinkler irrigated.
Phosphorus rates of 0, 20, 40, 80, and 120 lbs P 2 O 5 /a were preplant broadcast applied in late winter. Applied P was incorporated at the Republic and Greeley County sites; the Stevens County site was no-till except for strip-till, spring-applied nitrogen application. The treatments were replicated six times in Greeley and Republic Counties and five times at the Stevens County site. Grain yields were obtained by hand harvesting 20 feet of row from the center of each plot.

Results
Significant, large yield responses were obtained at both the Greeley and Stevens County locations. The large response at Stevens County was particularly interesting because the surface broadcast applications were not incorporated. Grain P contents were increased with increasing P application rate, whereas grain moisture declined.

Summary
Corn and grain sorghum studies have been initiated across the state to help refine the crop nutrient recommendations for corn and grain sorghum. This study included P rates of 0, 20, 40, 80, and 120 lbs P 2 O 5 /a and K rates of 0, 40, 80, and 120 lb K 2 O/a. All fertilizer was broadcast applied and incorporated with a disc. There was no response to applied P this year, but there was a 25-bu/a response to applied K (18%). In addition, the P and K content of the grain increased with increasing P rate, whereas the K content of the grain increased with increasing K application rate.

Introduction
Corn and grain sorghum studies have been initiated across the state to improve crop nutrient P and K recommendations. To meet this objective, the following information is being gathered; 1) average crop response to various rates of P and/or K application at various soil test values, 2) average percentage sufficiency (for maximum yield) at various soil test values, 3) amounts of P and K nutrient application/ crop removal to change soil test values, and 4) the amounts of P and K removed in the harvested grain.

Procedures
Studies involving both P and K were established at a Cherokee County location during the winter of 2003-04. Phosphorus soil tests ranged from 11-28 ppm Bray P1 and averaged 18 ppm across the whole study. Potassium soil test values ranged from 86-197 ppm exchangeable K and averaged 134 ppm.
Phosphorus rates of 0, 20, 40, 80, and 120 lbs P 2 O 5 /a and K rates of 0, 40, 80, and 120 lb K 2 O/a were broadcast applied in late winter and subsequently incorporated by the farmer/cooperator. The treatments were replicated five times and arranged in a randomized complete-block design. Grain yields were obtained by hand harvesting 20 feet of row from the center of each plot.

Results
The results of these Cherokee County studies are summarized in Tables 1 and 2. Neither grain yield or moisture was affected by P application, whereas grain nutrient P and K contents increased with increasing P application rate. Grain yield and grain K content were significantly increased by K application. Both yield and grain K content were still increasing at the highest rate of application.
In 2002, in an adjacent field, grain yields trended higher with increasing P application and were not affected by K application. Soil samples from individual plots will be collected during the fall-winter of 2004-05.

Summary
Growing concern over elevated groundwater NO 3 concentrations has emphasized the importance of efficient N management, particularly on coarse irrigated soils that are highly susceptible to NO 3 leaching. A 2-yr study evaluating corn response to N rate and timing was completed in 2004. Average grain yield achieved at eight study sites throughout Kansas ranged from 58 to 209 bu/a. Maximum grain yield was achieved at eight study sites over two years with a split application of 165 lb N/a, and in most instances a split application of 110 lb N/a was sufficient to achieve maximum yield. The optimum N rate observed for each study site was generally less than the corresponding KSU N recommendation, especially when N was split-applied.

Introduction
Nitrogen management is of particular concern in areas of Kansas where irrigated corn production commonly occurs on coarse-textured soils with high yield potential. Nitrogen applied in excess of that required for maximum grain yield can lead to elevated concentrations of NO 3 in the soil profile and an increased susceptibility to NO 3 loss by leaching. Timing of N fertilizer application is central to efficient use of N, particularly on sandy-textured soils that are susceptible to downward movement of NO 3 .
The negative environmental impacts associated with corn production can be minimized through efficient N management, including accurate N fertilizer recommendations. Recommendations for N must be formulated to address both yield concerns and environmental issues. The use of excess N, as an "insurance" mechanism, is perpetuated by the fact that a moderate amount of over-fertilization represents a smaller economic risk than a possible yield reduction associated with inadequate N. An improved effort is needed to confront the attitudes and motivations that influence the decisions concerning application rates of N fertilizer. Adjustments to the N recommendations currently used, such as reductions in N rate for more efficient N management or reductions in the yield goal factor used for some soil types (especially soils susceptible to N loss), will be an important part of this effort. Identifying N-and water-management practices that minimize the NO 3 leaching potential for corn production along Kansas rivers will be essential to improving N recommendations in this region, while maximizing economic return for Kansas producers. The objective of this study was to evaluate grain yield response to alternative N-and water-management strategies for irrigated corn in the sandy soils along major Kansas tributaries.

Field experiments in 2001 and 2002
were established along the Republican, Kansas, and Lower Arkansas Rivers. Locations included Scandia, Manhattan, Rossville, St. John, Ellinwood, and Pretty Prairie. Each field was in continuous corn under conventional tillage and was sprinkler-irrigated. Plot dimensions were 20 ft (8 rows, 30-in. row width) wide and 30 ft long. Nitrogen treatments were arranged in a randomized complete-block design (RCBD) and included: 0, 110, 165, and 220 lb/a (split applications, preplant and V6); and 220 and 270 lb/a (single preplant applications). Nitrogen treatments were adjusted at Pretty Prairie and St. John to accommodate producer N-management practices. There were two irrigation treatments at the Ellinwood site (optimal water rate, 1.0X, and 25% greater than optimal, 1.25X), each of which included a RCBD with the described N treatments. Soil samples were collected preplant and post-harvest to 8 ft (1-ft incr.), and at V6 to 2 ft (1-ft incr.). Grain yield at all sites except Rossville (plot combine used) was determined by hand harvesting a 20-ft length of each of the middle two rows from each plot. The N recommendation (NREC) for each site and year was determined by using the formula developed at KSU (2003).
Research data were used to compute each NREC. Yield goal for each site was determined by using the highest grain-yield mean (for a treatment) from the two research years. Soil profile N was calculated by using the average of pre-season sample NO 3 concentrations, 0 to 24 in, from a given site for each study year. Nitrogen credits from irrigation were calculated by using application rates estimated from actual field measurements or from values typical for each. Statistical analyses were performed according to General Linear Procedures (SAS), and F-tests for analysis of variance (ANOVA) were considered significant at the 0.10 probability level.

Results
Soil physical characteristics at these locations were representative of the sandy soils along Kansas' main rivers. Dry-bulkdensity values ranged from 1.31 to 1.81 g cm -3 across all locations and depths (Table  1), and sandy-textured soils were predominant in the 0-to 8-ft soil profile at each site, with sand content often exceeding 80% (Table 2).
Average grain yield at sites ranged from 58 to 209 bu/a. Maximum grain yield was achieved at eight study sites over two years with a split application of 165 lb N/a, and in most instances a split application of 110 lb N/a was sufficient to achieve maximum yield (Tables 3 and 4). The optimum N rate observed for each study site was generally less than the corresponding KSU NREC (Table 5), and was greater than the NREC for only Pretty Prairie West in 2001. For each location except Pretty Prairie West, the KSU NREC ranged between 156 and 270 lb N/a, corresponding to between 6 and 213 lb N/a in excess of that required to achieve maximum grain yield. On average, across all sites that responded to any N fertilizer, the NREC was 75 lb N/a greater than that required to reach maximum yield. The major contributor to maintaining crop yield with reduced rates of N fertilizer may be the increased recovery of N by the corn plant when N is split-applied. Split applications provide some measure of N use efficiency not accounted for in the KSU NREC, although a single preplant application of 220 lb N/a, 51 lb N/a less than the maximum NREC, was sufficient for maximum yield for all but one site year (Ellinwood 1.0X, 2001). The KSU NREC was similar to the minimum N rate to achieve maximum yield at the Manhattan and Pretty Prairie West locations, which had the lowest yield goals of all the study sites (Table 5). Results from this research indicate that corn N rates on these coarsetextured, irrigated soils can be reduced by an average of about 40% of the current NREC, when N is split-applied, while maintaining corn grain yields.

Introduction
Several corn and grain sorghum studies have been initiated across the state to improve crop nutrient P and K recommendations. To meet this objective, the following information is being gathered from various studies conducted across the state of Kansas; 1) crop response to various rates of P and/or K application at various soil test values, 2) percentage sufficiency (for maximum yield) at various soil test values, 3) amounts of P and K nutrient application/crop removal to change soil test values, and 4) The amounts of P and K removed in the harvested grain.
This project was initiated for the 2003 crop and will continue for the 2005 crop year.

Procedures
Soil samples from the 0-to 6-inch depth were collected from individual plots at some locations and from individual replications at others. Bray P1, Mehlich 3 colorimetric and Mehlich 3 ICP soil test procedures were run on individual samples. For this report, only the Bray P1 results will be presented.
All of the reported studies were located in farmer/cooperator fields and all locations were dryland. A fourth irrigated grain sorghum study was established at the Tribune Research Station in Greeley County, but had not dried enough for harvesting as of early November.
Phosphorus rates of 0, 20, 40, 80, and 120 lbs P 2 O 5 /a were preplant broadcast applied in late winter. Applied P was incorporated at the Republic and Ford County sites, whereas the Sheridan County site was a no-till location. The treatments were replicated six times at Ford and Republic Counties. Six replications were established at the Sheridan County location as well, but two replications were lost to drought. Grain yields were obtained by hand harvesting 20 feet of row from the center of each plot.

Results
Droughty conditions affected all locations, with the Sheridan County site being the most severely affected. As a result, significant variability existed in grain yield data at each site. However, grain yield was consistently improved with P applications at each location, although differences were not significant at traditional significance levels.

Summary
Since 1992, responses of grain sorghum to tillage system, N rate, N source, and N placement have been investigated. One half of the study has been continuous no-till and one half has been under conventional tillage. For 2004, N rates were 0, 30, 60, and 120 lb N/A broadcast applied in the spring. Nitrogen sources included urea, ammonium nitrate, and a polymer-coated, slow-release urea. Conventional tillage resulted in much higher grain yields at the lower N rates than no-till; however, conventional and no-till grain yields were similar at the high N rate examined. In general, all N sources performed similarly.

Introduction
Tillage methods can influence grain sorghum yields through a number of mechanisms. Residue that accumulates at the soil surface with no-tillage increases soil moisture and cools soil temperatures. Cool, wetter soils may affect N availability by altering the rate of microbial mineralization and immobilization. In addition, there is the potential for volatilization loss from unincorporated, surface-applied urea under certain conditions.
In addition to tillage system, this longterm study has evaluated several N management factors over the past 20 years, including N application rate, N application method, urease inhibitors, and more recently, slow-release urea.

Procedures
Three N sources at three rates (30, 60, and 120 lb N/a) were used. The three N sources used were ammonium nitrate, urea, and a slow-release urea N fertilizer. The conventional tillage includes fall chisel and field cultivation in the spring before planting. For the conventional tillage, the N was applied before spring cultivation. Treatments were replicated three times and arranged in a split-plot design, with tillage as the main plot treatment and N rate/source as split-plot treatments. Twenty feet of row were hand harvested from the center of each plot.

Results
Results are summarized in Table 1. Yields were increased with increasing N rate by all sources in both tillage systems. In general, both N sources performed similarly under conventional tillage, but urea and ammonium nitrate performed better than the slow-release product did under no-till at the lower N application rates. Conventional tillage resulted in much higher grain yields at the lower N rates than no-till; however, conventional and no-till grain yields were similar at the high N rate examined.
This research will continue in future years.

Yield
Tissue

Summary
Zinc fertilizer products of differing water solubility increased zinc soil test values in relationship to water solubility of products. The greater the water solubility, the more that DTPA Zn soil tests increased, regardless of Zn application rate. As the applied Zn rate increased, DTPA soil test values increased regardless of inorganic Zn source. Only the low rate of compost has been applied so far, and soil tests have changed very little in response to compost application.

Introduction
There are many zinc fertilizer products on the market, and these products often differ considerably in water solubility. Although questions about efficacy of these products to increase soil test values are often raised, there is little information on which to base an answer. Questions abound as to the effect of manure/compost on resulting Zn soil test values. Presented are preliminary results of a study initiated early in 2003.

Procedures
Locations of these zinc studies are distributed across a broad section of western Kansas. Dryland locations included Thomas, Ness, and Ford (near Dodge City) Counties. In addition, an irrigated site was established in Ford County (near Ford). Soil samples (0-6") were collected from each individual plot before fertilizer application. Products were broadcast applied.
Because of drought conditions, it was not possible to resample the Ness and Thomas County locations until 18 months after initial zinc product application. About 10 to12 individual soil cores were collected from each plot and combined into a composite sample, and the sample was then submitted to the laboratory for analysis.
Zinc products used included a zinc sulfate product (96% water soluble), an oxysulfate product (50% water solubility), an older zinc product with limited water solubility (15% water solubility), and a beef feedlot compost material.

Results
Although these results are preliminary, it seems that the efficacy of zinc fertilizer products is directly related to water solubility over the time frame studied. Follow-up sampling will continue in 2005 for these studies.

Location
Tillage NS 0.01 0.01 * Only the 5-lb Zn/a compost rate had been applied as of this fall on the 15 lb Zn/a plots. Additional compost will be applied this winter.

Introduction
The Bray P1 extractant has traditionally been the common extractant used for soil testing in the Midwest and Great Plains, whereas the Olsen P test has been the dominant phosphorus (P) extractant used in many western states. The use of the Mehlich-3 extractant for determining soil test P in private and state-operated soil test laboratories has become more commonplace in recent years. The ability to extract multiple elements is a major advantage of the Mehlich-3 test. Although the Mehlich-3 test is often run using the more traditional colorimetric procedure, the use of ICP in conjunction with the Mehlich-3 extractant is also becoming more commonplace as pricing declines. With changes in extractants and analytical techniques also comes the need to evaluate these new tests for agronomic and environmental-stewardship purposes. As part of a larger P management project, this study used 367 soil samples collected from 10 locations across Kansas and western Missouri that were analyzed by Bray P1 with colorimetric determination (BP1), Mehlich-3 with colorimetric determination (M3-Col), and Mehlich-3 with ICP determination (M3-ICP).

Procedures
A total of 367 soil samples were collected from individual plots at nine locations throughout Kansas and one from western Missouri. Selected soil properties for each location are presented in Table 1. Fifteen soil cores were collected from the 0to 6-inch depth for each sample location at each site. The samples were analyzed for Bray-P1 soil test P, soil pH was determined, and free lime estimates were done at the Kansas State University soil test laboratory. Mehlich-3 colorimetric and ICP determinations and soil organic matter were run by Servi-Tech soil test laboratory. All soil test determinations were made using the same dried and ground sample.

M3-Col and M3-ICP vs. Bray P1
In general, the M3-Col and BP1 procedure and the M3-ICP and BP1 procedures were well correlated at individual locations. The main exceptions were the Brown and the Dekalb sites (Table  2). It is unknown why these locations were so different from the rest of the sites. It is interesting that the Dekalb location was previously in pasture, with the sod being worked up in late winter 2003, and also had very low Bray P1 soil test values.
At Ellis County, 12 of the 90 samples collected contained appreciable amounts of free lime (calcareous soils). Although the correlations between both the M3-Col and M3-ICP procedures to the BP1 extractant were very good, many of these 12 samples appeared as outliers (Figure 1). These outliers resulted in lower-than-expected BP1 values relative to either Mehlich-3 determination. The r 2 value of the M3-ICP to BP1 comparison was not improved by removal of these soils (0.84 vs. 0.84), but the relationship of the M3-Col to BP1 was improved (0.79 to 0.85).
Both the M3-Col and M3-ICP methods were highly correlated with BP1 when all locations were combined for analysis ( Figure 2). Calcareous samples were excluded for this analysis. Overall, the M3-Col method extracted about 12% more P than the BP1 extractant. The M3-ICP extracted more P than either the M3-ICP or BP1 procedures did.

M3-Col and M3-ICP
The M3-Col and M3-ICP determinations were very highly correlated, with r 2 values exceeding 0.70 at all locations except for the Dekalb County site (r 2 = 0.35); the r 2 values were greater than 0.96 at seven of ten locations. Although it is unknown at this time why the Dekalb location provided such results, the differences at Dekalb County were striking. The average soil test values at this location were 3.6, 3.2, and 9.8 ppm for the BP1, M3-Col, and M3-ICP determinations, respectively. It is possible that the only recently disturbed pasture residues resulted in greater amounts of organic P being measured by the M3-ICP procedure, compared with either the BP1 or M3-Col procedure.
When the samples from all locations are combined (Fig. 3), including the calcareous soils, the M3-Col and M3-ICP determinations were very highly correlated (r 2 = 0.98). At low soil test values, however, the M3-ICP procedure extracted relatively more P than the M3-Col procedure did. Figure 3 presents the ratio of the M3-Col determination divided by the M3-ICP determination. The data clearly suggests that the relationship between M3-Col and M3-ICP varies depending on the relative P soil test levels. It is hoped that this relationship will become clearer as additional years of data are included.

Overall
The BP1 test was highly correlated with both the M3-Col and M3-ICP procedures, especially for non-calcareous soils (r 2 = 0.91-0.93). Likewise, M3-Col and M3-ICP were highly correlated across all soils (r 2 = 0.98). However, the relationship of M3-Col to M3-ICP differs, depending on the M3-Col soil test value. Additional work to further define this relationship and the relationship of each of these tests to crop response and grain nutrient content will continue.