Effect of Centibar Thresholds at Soybean Growth Stages on Yield and Water Use Efficiency.

Effect of Centibar Thresholds at Soybean Growth Stages on Yield and Water Use Efficiency Wilks Wood, L. J. Krutz, Trent Irby The Mississippi Alluvial River Valley aquafer is being depleted at distressing rates due to irrigation withdrawal for cotton, corn, soybeans and rice. Current irrigation practices adopted by producers typically result in overwatering crops at the VN to R2 and R6 to R7 growth stages. Also, the use of soil moisture sensors is relatively new to the Mid-South and knowledge of this new technology is currently inadequate in our region. To determine the effect of differing centibar thresholds at separate growth stages on water use efficiency and yield an experiment was conducted at the Delta Research and Extension Center located in Stoneville, Mississippi in 2015. Asgrow 4632 was planted on 26-April in a split-plot arrangement within a randomized complete block. The main plot factor were growth stages that consisted of VN to R2, R3 to R4, R5 to R6.5 and season long. Irrometer Watermark moisture sensors were used to determine when irrigation events should be initiated. The sub-plot factor was centibar thresholds which were 50, 85 and 125. Water use efficiency and yield results will be discussed. Results from this study will provide valuable insight into improving soybean production and water conservation in the Mid-South.