Effects of Cultural Best Management Practices Managed for Irrigation Benefits in Mid-Southern Irrigated Soybean Production.

Profitable Mid-Southern, USA soybean (Glycine max L.) production is dependent upon sustainable irrigation capabilities. Mid-Southern, USA agriculture predominantly utilizes furrow-irrigation delivery systems. Inefficiencies inherent to furrow-irrigation, including increased runoff volumes and reduced infiltration, result in application efficiencies of approximately 50%. Conservation tillage and cover crops have exhibited the ability to increase irrigation application efficiency in many regions of the world. Therefore, this study sought to determine the effects of conservation tillage practices and cover crops on soybean grain yield, irrigation application efficiency, and net returns above total specified costs when managed to provide maximum irrigation benefits. Seven treatments arranged in a randomized complete block (n=3) included conventional tillage winter fallow, reduced tillage winter fallow, reduced tillage with sub-soiling, reduced tillage with a cereal rye (Secale cereale L.) cover crop, reduced tillage with a tillage radish (Raphanus sativus L.) cover crop, zone tillage winter fallow, and zone tillage with a tillage radish cover crop. Experimental units (8.13-m wide by 153-m long) were separated by 3-m wide levees and planted with soybean at 345,935 seeds ha-1 and instrumented to mass balance irrigation water runoff volume. The final three year results will be presented to cover soybean grain yield, irrigation application efficiency, irrigation water use efficiency, and net returns above total specified costs. Effects of Cultural Best Management Practices Managed for Irrigation Benefits in Mid-Southern Irrigated Soybean Production