Nitrogen management for furrow-irrigated rice produced on silt-loam soils

Rice is typically produced under flooded conditions, but upward of 120,000 ha of furrow-irrigated rice (FIR) were produced in Arkansas and Missouri in 2020. Nitrogen management will inherently vary under FIR production due to greater N loss potential, especially via nitrification-denitrification stimulated by wetting and drying cycles of the soil. A series of trials were conducted from 2018 to 2020 to determine the optimum N management program for FIR grown on a silt-loam soil. Eight sites were used in a split-plot design, with the whole-plot factor being location within the field (top vs. bottom) and the split-plot factor being N management regime. The N management regimes ranged from a single application to a four-way split. Trial results suggest that multiple N management programs can maximize rice grain yield, including those with a greater number of N applications or season total N rate. The recovery efficiency of N ranged from 53.6 to 76.2% and the agronomic N efficiency ranged from 8.3 to 29.3 kg kg(-1). The findings suggest that three weekly applications of 52 kg N ha(-1) will allow FIR producers across the Mid-South to optimize their N management program, potentially increasing yield and decreasing environmental effects resulting from the transition to FIR.

Automated summary

This study discusses nitrogen management in furrow-irrigated rice (FIR) and finds that multiple nitrogen management programs can maximize rice grain yield, including increasing the number of nitrogen applications or the total nitrogen rate. The study also suggests that three weekly applications of 52 kg N ha(-1) can optimize nitrogen management program, potentially increasing yield and reducing environmental effects.