Alkaline Hydrolyzable‐Nitrogen of Clayey Soils Reduces Supplemental Fertilizer Nitrogen Requirement of Rice in Arkansas

The Illinois Soil Nitrogen Test (ISNT) and the Nitrogen Soil Test for Rice (N‐STaR) are alkaline hydrolyzable‐N (AH‐N) soil test methods that can potentially improve N fertilization of cereal crops by predicting a site‐specific fertilizer‐N rate; however, neither method has been evaluated for rice ( Oryza sativa L.) grown on clayey soils. The study objectives were to: (i) evaluate unfertilized (0 kg N ha −1 ) N uptake and yield response of rice...