Profit-Maximizing Potash Fertilizer Recommendations for Rice.

Potassium (K) fertilizer recommendations for rice (Oryza sativa L) decrease as the amount of initial soil-test K increases until a point where no fertilizer K is recommended. These recommendations are primarily based on observed agronomic yield response trials conducted across time. Since rice price, fertilizer cost, and initial soil-test K values play roles in developing profit-maximizing fertilizer use, this analysis compares current K₂O fertilizer rate recommendations to rates estimated by maximizing profit and yield-maximizing rates. Using the last ten years of rice and fertilizer prices, we conclude that application recommendations should be revised to lower fertilizer-K application rates. [ABSTRACT FROM AUTHOR]