In light of the voluntary metering program coupled with the perception that stricter regulation on groundwater withdrawal is imminent, producers asked Mississippi State University Research and Extension personnel to develop and evaluate methods that improve furrow irrigation application efficiency. Per this request, the Row-crop Irrigation Science and Extension Research (RISER) Program was developed and worked in concert during the 2013 growing season with the Cotton (Cotton DEMO Program), Corn (Corn Verification Program), Soybean (SMART Program) and Rice Extension Specialists to evaluate the impact of irrigation Best Management Practices (BMPs) on water savings potential across the Delta. The 2013 RISER extension effort exceeded our expectations and highlights the potential for irrigation BMPs to significantly reduce irrigation withdrawals from the Mississippi Alluvial Aquifer.
Following is a summary of the 2013 RISER Program results. Seventeen production scale irrigation sets optimized by MSU extension personnel were paired side-by-side with irrigation sets controlled by producers. Extension locations ranged from south of Lake Washington, MS to north of Tunica, MS and encompassed the three major soil types encountered across the Delta, including: cracking clay, mixed, and traditional silt-loam, cotton soils. Corn and soybean yields were not statistically different between RISER and producer irrigation sets (Figure 1). However, water use was reduced by 47% in RISER controlled irrigation sets as compared to producer controlled sets. Our results indicate that if producers adopt the RISER irrigation philosophy, yield potential can be maintained while reducing withdrawal from the Mississippi River Alluvial Aquifer by approximately 50%.
How did RISER reduce irrigation water use by approximately 50% while maintaining yield potential? The RISER program reduced irrigation water use by optimizing both furrow irrigation application efficiency and timing. Irrigation application efficiency was optimized using two methods. The first method was computerized hole selection, i.e., PHAUCET or Delta Plastics Pipe Planner. Computerized hole selection helps one optimize irrigation set size while ensuring that all furrows reach the tail-ditch in approximately the same time. The second tool utilized by RISER to improve furrow irrigation application efficiency was surge irrigation. Surge irrigation is a furrow irrigation technique that optimizes irrigation application efficiency by reducing deep percolation losses, i.e., over-saturation of the soil profile along the poly-ethylene tubing, and tail-water runoff. Finally, and perhaps most importantly, RISER reduced irrigation water use by approximately 50% by utilizing soil moisture sensor technology to optimize irrigation application timing.
In summary, RISER results indicate the potential for computerized hole selection (PHAUCET or Pipe Planner), surge irrigation and soil moisture sensors to reduce irrigation water use by approximately 50% while maintaining yield potential and profitability. As planting and irrigation season approaches, we will blog specifically on computerized hole selection, surge irrigation, soil moisture sensors, and how we used these tools in concert across the Mississippi Delta to improve water use efficiency and profitability.