Withdrawal for agricultural uses has decreased water levels in the Mississippi Alluvial River Valley aquifer (MARVA), and Mississippi state regulators have responded by requiring withdrawal permits, establishing permitted withdrawal limits, and instituting required minimum levels of irrigation water use efficiency (IWUE) practices. The objective of this research was to determine the effect of integrating irrigation water management (IWM) practices-including computerized hole selection (CHS), surge flow irrigation (SURGE), and sensor-based irrigation scheduling-on irrigation water use, soybean grain yield, IWUE, and net returns above irrigation costs at the production scale. The experiment was conducted in the Prairie region of Arkansas and the Delta region of Arkansas and Mississippi from 2013 through 2015. The research consisted of 20 paired fields, with the same cultivar, soil type, planting date, and management practices. One field was randomly assigned as the control (conventional, CONV) and the other was instrumented with CHS, SURGE, and soil moisture sensors, that is, IWM. Flowmeters were installed in the inlets to both fields, and the farmers provided yield data. Soybean grain yield averaged 69.0 bu/acre and did not differ between CONV and IWM (P = 0.6703). Relative to CONV, IWM reduced water use 21% (P = 0.0198) and increased IWUE 36% (P = 0.0.0194). Net returns for soybean production above irrigation costs were not different between CONV and IWM, even when pumping depth ranged from 18 ft to 400 ft and diesel costs ranged from $1.60/gal to $3.70/gal (P ³ 0.5376). These results demonstrate that implementation of integrated IWM at the production scale reduces the demand on depleted groundwater resources without adversely affecting soybean grain yield or on-farm profitability.

Irrigation water management practices decreased total water applied by 39.5%.• Irrigation water management practices increased corn grain yield by 6.5 bu/acre.• Irrigation water management practices increased irrigation water use efficiency by 51.3%.

The Mississippi River Valley Alluvial Aquifer is declining precipitously due to irrigation withdrawal for row crop production. Currently, 25% of the soybean (Glycine max L.) acres in the Mid-South are planted on clay-textured soils and furrow-irrigated using conventional continuous flow (CONV), the least efficient irrigation delivery system. The objective of this research was to determine the effect of surge irrigation (SURGE) on amount of water applied, soybean grain yield, irrigation water use efficiency (IWUE), and net return above irrigation costs when implemented on clay-textured soils. The research was conducted during the 2013 through 2015 growing seasons in Stoneville, MS and consisted of paired fields, with the same cultivar, soil texture, planting date, and management practices used on both sites. Paired fields were randomly assigned as SURGE or CONV. Water applied to each field was monitored with flowmeters, and irrigations were initiated based on soil moisture sensor thresholds. Relative to CONV, SURGE reduced the amount of water applied per irrigation event by 22% and total water applied in season by 24% (P £ 0.0349). Soybean grain yield averaged 66 bu/acre and was not different between delivery systems (P = 0.7711), but SURGE increased IWUE by 29% compared with CONV (P = 0.0076). Net return above irrigation cost was not different between CONV and SURGE, regardless of diesel price or pumping depth (P ³ 0.1149). Results from this research indicate that soybean producers in the Mid-South and other regions that irrigate using lay-flat polyethylene tubing can adopt SURGE for soybean on clay-textured soils without adversely affecting yield or on-farm profitability while concurrently decreasing the demand on depleted groundwater resources.