Abstract: A limited irrigation study involving four cropping systems and evaluating four crop rotations was initiated in 2012 at the Southwest Research-Extension Center near Tribune, KS. The cropping systems were two annual systems (continuous corn [C-C] and continuous grain sorghum [GS-GS]) and two 2-year systems (corn-grain sorghum [C-GS] and corn-winter wheat [C-W]). In 2019, corn yields were similar for all rotations, although averaged across the past 7 years, corn yields were greater following wheat than following corn. There were no significant differences in grain sorghum yields in 2019, which was similar to the multi-year average. Wheat yields were greater than 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 corn in western Kansas. In 2019, N applied alone increased yields by 71 bu/a, whereas P applied alone increased yields 10 bu/a. Nitrogen and P applied together increased yields up to 131 bu/a, which is 10 bu/a less than the 10-year average of 141 bu/a. Application of 120 lb N/a (with highest P rate) produced 97% of maximum yield in 2019, which is slightly greater than the 10-year average. Application of 80 instead of 40 lb P2O5/a increased average yields 4 bu/a. 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 41% and apparent fertilizer phosphorus recovery in the grain (AFPRg) was 60%.
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 2019, N applied alone increased yields 66 bu/a, whereas N and P applied together increased yields up to 85 bu/a. Averaged across the past 10 years, N and P fertilization increased sorghum yields up to 78 bu/a. Application of 160 lb/a N (with P) produced the maximum yield in 2019, which is slightly more than the 10-year average. Application of potassium (K) has had no effect on sorghum yield throughout the study period. Average grain N content reached a maximum of ~0.7 lb/bu while grain P content reached a maximum of 0.16 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 31% for N, 65% for P, and 38% for K.
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