Rice Yield and Aboveground Biomass Response to Nitrogen Additions.

Rice (Oryza sativa L.) is a crop predominantly grown in the Mid-South. Current Mississippi State recommendations for N in rice production is a single application of 168 kg of total N/ha on sandy soils and 201.6 kg of N/ha-1 on its clay soils. Our primary objective is to find an alternative N management strategy that can potentially be used to eliminate the cost associated with an aerial application common in delayed-flood rice production common in the Mid-South. Research will be established at the Delta Research and Extension Center, at Stoneville, MS on both sandy loam and clay soils, all experimental design was a split-plot. N sources being evaluated are Environmentally Smart Nitrogen (ESN), Ammonium sulfate (AMS), Diammonium Phosphate (DAP), Agrotain treated urea, and urea. Timings were established at planting, 2-leaf growth stage, 7 days before flood, and midseason with a yearly total rate of 168 kg ha-1, plus an untreated check. After year one of data Agro-7DBF produced the greatest number of tillers and aboveground biomass at both sample timings (HDN and PD). ESN-2LF produced numerically the greatest but significantly the same as Agro-7DBF, ESN-DAP-, ESN+MS and ESN-7DBF; the importance of this data proves that N fertilizer can be applied early from a ground rig before the levee system has been established and eliminate the use of aerial applications.