RISER Row-crop Irrigation Science Extension and Research Agronomic Practices And Irrigation Management Strategies That Optimize Soybean Water Use Efficiency Wilks Wood

Delta Issues Aquifer decline Permitted values Metering program Increased regulation

Prior Research

Yield by Planting Date and Maturity Group Early Planting Date Mid Planting Date Late Planting Date

Early Planting Date Mid Planting Date Late Planting Date

Early Planting Date Mid Planting Date Late Planting Date

Early Planting Date Mid Planting Date Late Planting Date

Irrigation Water Use Efficiency P<.01 Early Planting Date Mid Planting Date Late Planting Date

Early Planting Date Mid Planting Date Late Planting Date

Early Planting Date Mid Planting Date Late Planting Date

Early Planting Date Mid Planting Date Late Planting Date

Row Spacing by Plant Population

1. Computerized hole selection RISER Cost Per Year 3. Soil sensors 2. Surge irrigation 1. Computerized hole selection

Irrigation Application Efficiency Pipe Planner Type/Size of Polytubing Size/Quantity of holes Application efficiency $10/Acre savings

Irrigation Application Efficiency Surge Results Reduces surface runoff losses Decreases deep percolation losses Improves infiltration sealing soils Application efficiency 25% higher than conventional

Irrigation Application Efficiency Cracking Clays Anecdotal evidence indicates efficiency approaches 30% Efficiency is a function of furrow length in cracking clays Preliminary data indicated up to 35% reduction in water use

Plant Available Water 50% MAD -1500 cbar -33 cbar 0 cbar

Soil Moisture Sensor Reading

Moisture Sensors Yield

Moisture Sensors Yield (IWUE)

On-Farm Evaluations Producer Riser P-value 69.3 11.5 7.2 543 68.6 9.1 Yield Water Use WUI Return ---Bu/acre--- ---Acre-in--- --Bu/acre-in-- -----$----- Producer 69.3 11.5 7.2 543 Riser 68.6 9.1 9.8 556 P-value 0.6703 0.0198 0.0194 0.5376 N = 20 farms Mississippi and Arkansas 7% of the population exceeded permitted value, 18 acre-in/yr 79% population applied more irrigation water than RISER 21% population applied less water than RISER

Conclusion Plant Early.

Conclusion Plant Early. Highest yield potential and irrigation water use efficiency.

Conclusion Plant Early. Highest yield potential and irrigation water use efficiency. Maturity Group IV great choice.

Conclusion Plant Early. Yield increase with < 30” rows. Highest yield potential and irrigation water use efficiency. Maturity Group IV great choice. Yield increase with < 30” rows.

Conclusion Plant Early. Yield increase with < 30” rows. Highest yield potential and irrigation water use efficiency. Maturity Group IV great choice. Yield increase with < 30” rows. Utilize tools available.

Conclusion Plant Early. Yield increase with < 30” rows. Highest yield potential and irrigation water use efficiency. Maturity Group IV great choice. Yield increase with < 30” rows. Utilize tools available. Computerized hole selection, SURGE valve and moisture sensors.

Acknowledgements Mississippi Soybean Promotion Board Summer Workers Fellow Graduate Students Committee Members

Questions Wilks Wood wwood@drec.msstate.edu