Long-Term Nitrogen and Phosphorus Fertilization of Irrigated Grain Sorghum

Authors

A. Schlegel, Kansas State UniversityFollow
H. D. Bond, Kansas State UniversityFollow

Keywords

Nitrogen fertilization, phosphorus fertilization, irrigated grain sorghum, long-term fertility, nutrient removal

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 2015, N applied alone increased yields 66 bu/a, whereas N and P applied together increased yields up to 92 bu/a. Averaged across the past 10 years, N and P fertilization increased sorghum yields up to 76 bu/a. Application of 40 lb/a N (with P) was sufficient to produce 88% of maximum yield in 2015 which is slightly above 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 0.15 lb/bu (0.34 lb P₂O₅/bu) and grain K content reached a maximum of 0.19 lb/bu (0.23 lb K₂O/bu).

Recommended Citation

Schlegel, A. and Bond, H. D. (2016) "Long-Term Nitrogen and Phosphorus Fertilization of Irrigated Grain Sorghum," Kansas Agricultural Experiment Station Research Reports: Vol. 2: Iss. 6. https://doi.org/10.4148/2378-5977.1244