A. Schlegel, F. Lamm, and D. O'Brien
Abstract: Research was conducted at Colby and Tribune, KS, from 2018–2020 to evaluate irrigation strategies, hybrid maturity, and seeding rate on corn production. Irrigation strategies were a combination of irrigation frequency/timing (weekly or bi-weekly) applied pre- and post-silking, and irrigation amounts (1 and 1.5 inch/week). Hybrid maturities were 108- and 111-day hybrids planted at 25,000 and 30,000 seeds/a. Average irrigation amounts ranged from 7.33 to 12.50 in. at Colby and 8.41 to 13.44 in. at Tribune. At Colby, average corn yields were not affected by irrigation strategies or seeding rate but were 8 bu/a greater with the 108-day hybrid. At Tribune, average corn yields were greater with weekly post-silking irrigation and with the higher seeding rate but not affected by hybrid maturity. The water limitations in this study are relatively severe and these results might not replicate under less stressful irrigation regimes.
Abstract: A limited irrigation study involving four cropping systems and evaluating four crop rotations was initiated at the Southwest Research-Extension Center near Tribune, KS, in 2012. The cropping systems were two annual systems (continuous corn and continuous grain sorghum) and two 2-year systems (corn-grain sorghum and corn-winter wheat). In 2020, corn yields were similar for all rotations, although averaged across the past 8 years, corn yields were greater following wheat than following corn. There were no significant differences in grain sorghum yields in 2020, which was similar to the multi-year average. Wheat yields were below the multi-year average.
A. Schlegel and H. D. Bond
Abstract: 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 2020, N applied alone increased yields 60 bu/a, whereas N and P applied together increased yields up to 83 bu/a. Averaged across the past 10 years, N and P fertilization increased sorghum yields up to 82 bu/a. The application of 160 lb/a N (with P) produced the maximum yield in 2020, which is slightly less than the 10-year average (2011–2020). The application of potassium (K) has had no effect on sorghum yield throughout the study period. The 10-year average grain N content reached a maximum of ~0.7 lb/bu while grain P content reached a maximum of 0.15 lb/bu (0.34 lb P2O5/bu) and grain K content reached a maximum of 0.19 lb/bu (0.23 lb K2O/bu). At the highest N, P, and K rate, apparent fertilizer recovery in the grain was 33% for N, 69% for P, and 40% for K. Nitrogen fertilization increased soil organic matter and decreased soil pH. Phosphorus fertilization tended to maintain or increase soil test P levels.
A. Schlegel and H. D. Bond
Abstract: Long-term research shows that phosphorus (P) and nitrogen (N) fertilizer must be applied to optimize production of irrigated corn in western Kansas. In 2020, N applied alone increased yields by 85 bu/a, whereas P applied alone increased yields 10 bu/a. Nitrogen and P applied together increased yields up to 136 bu/a which is 11 bu/a less than the 10-year average of 147 bu/a. The application of 120 lb N/a (with highest P rate) produced 98% of maximum yield in 2020, which is greater than the 10-year average (2011–2020). The application of 80 instead of 40 lb P2O5/a increased average yields 1 bu/a. The 10-year average grain N content reached a maximum of 0.6 lb/bu while grain P content reached a maximum of 0.15 lb/bu (0.34 lb P2O5/bu). At the highest N and P rate, apparent fertilizer nitrogen recovery in the grain (AFNRg) was 43% and apparent fertilizer phosphorus recovery in the grain (AFPRg) was 63%. Nitrogen fertilization increased soil organic matter and decreased soil pH. Phosphorus fertilization at 40 lb/a P2O5 was not sufficient to maintain soil test levels.
Schlegel, A.J. and J. L. Havlin. 2020. Irrigated grain sorghum response to 55 years of nitrogen, phosphorus, and potassium fertilization. Agron. J. n/a:n/a. DOI:10.1002/agj2.20453
Schlegel, A.J., Y. Assefa, and D. O`Brien. 2020. Productivity and profitability of four crop rotations under limited irrigation. Applied Eng. Agric. 36(1):1-9. DOI:10.13031/aea.13416
Rudnick, D. R., S. Irmak, C. West, I. Kisekka, T.H. Marek, J. Schneekloth, D. Mitchell McCallister, V. Sharma, K. Djaman, J. Aguilar, J.L. Chávez, M. Schipanski, D.H. Rogers, A.J. Schlegel. 2019. Deficit irrigation management of maize in the High Plains Aquifer region: A review. Journal of the American Water Resources Association. DOI:10.1111/1752-1688.12723
Rogers, D.H., A.J. Schlegel, J.D.Holman, J.P. Aguilar, and I. Kisekka. 2016. Irrigation of grain sorghum. p. 13. In I.A. Ciampitti and P.V.V. Prasad (eds.) Sorghum: State of the Art and Future Perspectives. Agron. Monogr. 58. ASA and CSSA, Madison, WI. doi:10:2134/agronmonogr58.2014.0072
Kisekka, I. A.J. Schlegel, L. Ma, P.H. Gowda, and P.V.V. Prasad. 2017. Optimizing preplant irrigation for maize under limited water in the High Plains. Agric. Water Mgmt. 187:154-163. DOI:10.1016/j.agwat.2017.03.023
Adee, E., K. Roozeboom, G.R. Balboa, A.J. Schlegel, and I.A. Ciampitti. 2016. Drought-tolerant corn hybrids yield more in drought-stressed environments with no penalty in non-stressed environments. Front. Plant Sci. 7:1534. doi: 10.3389/fpls.2016.01534
Schlegel, A.J., Y. Assefa, T.J.Dumler, L.A. Haag, L.R. Stone, A.D. Halvorson, and C.R. Thompson. 2016. Limited irrigation of corn-based no-till crop rotations in west central Great Plains. Agron. J. 108:1132-1141. DOI: 10.2134/agronj2015.0536
Schlegel, A.J., Y. Assefa, D. O’Brien, F.R. Lamm, L.A. Haag, and L.R. Stone. 2016. Comparison of corn, grain sorghum, soybean, and sunflower under limited irrigation. Agron. J. 108:670-679. DOI: 10.2134/agronj2015.0332