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Southwest Research Center – Tribune

Contact Info

Southwest Research Center - Tribune
1474 State Highway 96
Tribune, Kansas 67879
Phone: (620) 376-4761
Fax: (620) 376-2278

Fertility

Long-Term Nitrogen, Phosphorus and Potassium Fertilization of Irrigated Grain Sorghum

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 2018, N applied alone increased yields 44 bu/a, whereas N and P applied together increased yields up to 67 bu/a. Averaged across the past 10 years, N and P fertilization increased sorghum yields up to 75 bu/a. Application of 80 lb/a N (with P) produced the maximum yield in 2018, which is slightly less than the 10-yr 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 0.15 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 31% for N, 65% for P, and 38% for K.

Long-Term Nitrogen and Phosphorus Fertilization of Irrigated Corn

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 2018, N applied alone increased yields by 76 bu/a, whereas P applied alone increased yields by more than 17 bu/a. Nitrogen and P applied together increased yields up to 169 bu/a. This is 26 bu/a more than the 10-year average, where N and P fertilization increased corn yields up to 143 bu/a. Application of 120 lb/a N (with highest P rate) produced 97% of the maximum yield in 2018, which is slightly greater than the 10-year average. Application of 80 instead of 40 lb P2O5/a increased average yields 9 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 43% and apparent fertilizer phosphorus recovery in the grain (AFPRg) was 62%.

Related Publications

  • Obour, A.K., A.J. Schlegel, R. Perumal, J.D. Holman, D. Ruiz Diaz. 2019. Evaluating grain sorghum hybrids for tolerance to iron chlorosis. J. Plant Nutrition. DOI:10.1080/01904167.2018.1549677

  • Schlegel, A.J., Y. Assefa, H.D. Bond, L.A. Haag, and L.R. Stone. 2017. Changes in soil nutrients after 10 years of cattle manure and swine effluent application. Soil Tillage Res. 172:48-58. DOI: 10.1016/j.still.2017.05.004

  • Schlegel, A.J. and J.L. Havlin. 2017. Corn yield and grain nutrient uptake from 50 years of nitrogen and phosphorus fertilization. Agron. J. 109:335-342. DOI: 10.2134/agronj2016.05.0294

  • Schlegel, A.J., Y. Assefa, H.D. Bond, S.M. Wetter, and L.R. Stone. 2015. Corn response to long-term applications of cattle manure, swine effluent, and inorganic N fertilizer. Agron. J. 1701-1710. DOI: 10.2134/agronj14.0632

  • Schlegel, A.J., Y. Assefa, H.D. Bond, S.M. Wetter, and L.R. Stone. 2015. Soil physicochemical properties after 10 years of animal waste application. Soil Sci. Soc. Am. J. 79:711-719. DOI: 10.2136/sssaj2014.11.0461

  • Sohm, G., C.R, Thompson, Y. Assefa, A.J. Schlegel, and J. Holman. 2014. Yield and quality of bermudagrass as a function of nitrogen rate. Agron. J. 106:1489-1496