Current Research Projects
- Irrigation of Corn with Diminished Well Capacities (PDF)
Alan Schlegel, Loyd Stone, Troy Dumler, Freddie Lamm
Many of the irrigation systems today in the Central Great Plains no longer have the capacity to apply peak irrigation needs during the summer and must rely on soil water reserves to buffer the crop from water stress. Considerable research was conducted on preseason irrigation in the US Great Plains region during the 1980s and 1990s. In general, the conclusions were that in-season irrigation was more beneficial than preseason irrigation and that often preseason irrigation was not warranted. The objective of this study was to determine whether preseason irrigation would be profitable with today’s lower capacity wells. A field study was conducted at the KSU-SWREC near Tribune, KS, from 2006 to 2009. The study was a factorial design of preplant irrigation (0 and 3 in), well capacities (0.1, 0.15, and 0.20 in day-1 capacity), and seeding rate (22,500, 27,500, and 32,500 seeds a-1). Preseason irrigation increased grain yields an average of 16 bu a-1. Grain yields were 29% greater when well capacity was increased from 0.10 to 0.20 in day-1. Crop productivity was not significantly affected by well capacity or preseason irrigation. Preseason irrigation was profitable at all well capacities. At well capacities of 0.10 and 0.15 in day-1, a seeding rate of 27,500 seeds a-1 was generally more profitable than lower or higher seeding rates. A higher seeding rate (32,500 seeds a-1) increased profitability when well capacity was increased to 0.2 in day-1.
- Crop and Soil Responses to Land Application of Cattle and Swine Waste (PDF)
Alan Schlegel, L Stone, HD Bond, M. Alam
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 for ten years at rates to meet estimated corn phosphorus (P) or nitrogen (N) requirements along with a rate double the N requirement. Other treatments were N fertilizer (60, 120, and 180 lb/a N) and an untreated control. Corn yields were increased by application of animal wastes and N fertilizer. When applied on an N-basis, corn yields averaged 18 bu/a greater from cattle manure than swine effluent. Over application of cattle manure has not had a negative effect on corn yield, while over application of swine effluent reduced corn yields in one year. Total N, organic C, and soil test P in the surface soil were increased more by application of cattle wastes than from swine effluent. The amount of increase in soil N, C, and P reflected the rate of application of both cattle and swine wastes. Application of N fertilizer had little effect on surface soil chemical properties. Nitrate concentration in the soil profile was increased by application of animal wastes with concentrations exceeding 100 ppm from the P-based swine effluent treatment. However, when animal wastes were applied on an N-basis, NO3 concentrations in the soil profile were not significantly greater than the control or N fertilizer treatments.
- No Till and Crop Rotations in Western Kansas (PDF)
Alan Schlegel, Troy Dumler, John Holman, and Loyd Stone
Grain yields of wheat and grain sorghum increased with decreased tillage intensity in a wheat-sorghum-fallow (WSF) rotation. Averaged over the past 10 years, no-till (NT) wheat yields were 6 bu/a greater than reduced tillage and 9 bu/a greater than conventional tillage. In 2010, grain sorghum yields were 58 bu/a greater with long-term NT than short-term NT. Averaged across the past 10 years, sorghum yields with long-term NT have been twice as great as short-term NT (57 vs. 26 bu/a). Grain yield of recrop wheat averaged about 80% of the yield of wheat following sorghum in a 4-yr rotation of wheat-wheat-sorghum-fallow. Grain yield of continuous wheat averaged about 70% of the yield of wheat grown in a 4-year rotation following sorghum. Wheat yields were similar following one or two sorghum crops. Similarly, average sorghum yields were the same following one or two wheat crops. Yield of the second sorghum crop in a wheat-sorghum-sorghum-fallow rotation averaged about 70% of the yield of the first sorghum crop.
- Land Application of Animal Wastes on Irrigated Corn (PDF)
Alan Schlegel, Loyd Stone, H. Dewayne Bond, and Mahbub Alam
Animal wastes are routinely applied to cropland to recycle nutrients, build soil quality, and increase crop productivity. This study evaluates established best management practices for land application of animal wastes on irrigated corn. Swine waste (effluent water from a lagoon) and cattle waste (solid manure from a beef feedlot) have been applied annually since 1999 at rates to meet estimated corn P requirements, corn N requirements, or a rate double the N requirement. Other treatments were 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.
- Long-Term Nitrogen and Phosphorus Ferilization on Yield of Irrigated Corn (PDF)
Long-term research shows that phosphorus (P) and nitrogen (N) fertilizer must be applied to optimize production of irrigated corn in western Kansas. In 2006, N and P applied alone increased yields about 70 and 30 bu/a, respectively; however, N and P applied together increased yields up to 160 bu/a. Averaged across the past 10 years, corn yields were increased up to 125 bu/a by N and P fertilization. Application of 120 lb N/a (with P) was sufficient to produce maximum yields in 2006, which was slightly more than the 10-year average. Phosphorus increased corn yields in 2006 an average of more than 100 bu/a when applied with at least 120 lb N/a. Application of 80 instead of 40 lb P2O5/a increased yields 20 bu/a when applied with at least 120 lb N/a.
- Four-Year Crop Rotations w/ Wheat and Grain Sorghum (PDF)
Alan Schlegel, Troy Dumler, and Curtis Thompson
Research on four-year crop rotations with wheat and grain sorghum was initiated at the K-State Southwest Research-Extension Center near Tribune in 1996. The rotations were wheat-wheat-sorghum-fallow (WWSF) and wheat-sorghum-sorghum-fallow (WSSF), along with continuous wheat (WW). Soil water at wheat planting averages about 9 inches following sorghum, which is about 3 inches more than the second wheat crop in a WWSF rotation. Soil water at sorghum planting is approximately 1.5 inches less for the second sorghum crop compared to sorghum following wheat. Fallow efficiency prior to wheat was greater for the shorter fallow period following wheat than for the longer fallow following sorghum. Prior to sorghum, average fallow efficiency was 38-40% and not affected by the previous crop. Grain yield of continuous wheat averages about 75% of the yield of wheat grown in a four-year rotation following sorghum. Except for one year, there has been no difference in yield of continuous wheat and recrop wheat grown in a WSF rotation. Yields are similar for wheat following one or two sorghum crops. Similarly, average sorghum yields were the same when following one or two wheat crops. Yield of the second sorghum crop in a WSSF rotation averages about 70% of the yield of the first sorghum crop.
- No-Till Limited Irrigated Cropping Systems (PDF)
Alan Schlegel, Loyd Stone, and Troy Dumler
Research was initiated under sprinkler irrigation to evaluate limited irrigation in a no-till crop rotation. With limited irrigation (10 inches annually), continuous corn was more profitable in 2006 than were multi-crop rotations including wheat, sorghum, and soybean. Averaged across the past 4-yr, continuous corn has been the most profitable system primarily because of spring freeze and hail damage to the wheat in the multi-crop rotations. In multi-crop rotations, relatively poor results with one crop (in this case wheat) can reduce profitability compared to a monoculture especially when the monoculture crop does well. However, the multi-crop rotation may reduce economic risk when the monoculture crop does not perform so well. All of the multi-crop rotations had net returns only $20/acre less than continuous corn so only relatively small changes in prices or yields would be needed for any of the rotations to be more profitable than continuous corn indicating the potential for alternate crop rotations under limited irrigation.
- Effect of Tillage Intensity in a Wheat-Sorghum-Fallow Rotation (PDF)
Alan Schlegel, Loyd Stone, Troy Dumler, and Curtis Thompson
Grain yields of wheat and grain sorghum increased with decreased tillage intensity in a wheat-sorghum-fallow (WSF) rotation. Averaged across the past 16 years, no-till wheat yields were 4 bu/a greater than with reduced tillage and 8 bu/acre greater than with conventional tillage. In 2006, wheat yields were very low but no-till produced 16 bu/a while reduced or conventional tillage resulted in almost complete failure. Grain sorghum yields were also low in 2006 and similar to wheat, no-till sorghum yielded 29 bu/a while conventional or reduced tillage sorghum yielded less than 5 bu/a. Averaged across the past 16 years, no-till sorghum yields were 14 bu/a greater than with reduced tillage and 33 bu/acre greater than with conventional tillage. Averaged across the past 6 years, sorghum yields were 25 bu/a greater with long-term no-till compared to short-term no-till. Skip Row Corn for Improved Drought Tolerance Alan Schlegel Research on skip row planting of dryland corn was initiated at the K-State Southwest Research-Extension Center near Tribune in 2004. The objective was to determine whether some pattern of skipping rows would improve drought tolerance of dryland corn. The planting arrangements were to plant one row and skip one (P1S1); plant two rows and skip one (P2S1); plant two rows and skip two (P2S2); and plant every row (P-All). Target plant populations were 10,000, 15,000, and 20,000 plants per acre. Corn was no-till planted into standing wheat stubble in early May of each year from 2004 to 2006. Corn yields were above average in 2004 and 2005, with yields above 90 bu/a in both years. In these high-yielding years, corn planted every row at a plant population of 15,000 acre-1 produced the highest yields; however, the P1S1 arrangement produced similar yields. The other two planting arrangements (P2S1 and P2S2) tended to reduce yield. In 2006, yields were less than 50 bu/a and corn planted every row at 15,000 plantsa again produced the best yields, although similar yields were obtained with all other planting arrangements. Plant population had more impact on yield that skip row planting. In 2004, with yields in excess of 100 bu/a, yields increased with plant population, while in 2006, with much lower yield potential, yields were generally better with lower plant populations. Overall, yields similar to those of every-row planting could be obtained with skip-row planting in low- and high-yielding years; however, skip-row planting did not result in higher yields than every-row planting in any year.
- Long-Term Nitrogen and Phosphorus Fertilization on Yield of Irrigated Grain Sorghum (PDF)
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 2006, N and P applied alone increased yields about 50 and 18 bu/a, respectively; while 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 2006 and for the 10-year average. Application of K has had no effect on sorghum yield throughout the study period.