Cotton Response to Irrigation Timing and Use of Enhanced Efficiency Nitrogen Fertilizer and Biosolids

Timing  irrigation initiation to avoid pre-flower water deficits has been shown to improve earliness and increase cotton yields in Arkansas. This work was expanded in 2010 to examine how changes in irrigation timing affect N use efficiency.  A field study in Northeast Arkansas was designed as a 3* 4 factorial experiment with irrigation timing (3 factors) and N fertilizer (4 factors) arranged in a split plot with irrigation  as main plots. Furrow irrigation was initiated either during the 2^nd week of squaring or was delayed 2 additional weeks (first flowers). A non irrigated control was included.  Fertilizer was applied prior to planting at 100 lb N/acre either as urea, enhanced efficiency N (trade name ESN) or urea + 300 lb/A biosolid (trade name Top Choice). An unfertilized check  (0 N) also was included.    Plant monitoring from the early squaring period until defoliation was performed using the COTMAN system. Treatment effects on biomass, leaf and petiole N, yield, and lint quality will be discussed.