Effects of low-till parabolic subsoiling frequency and furrow irrigation frequency on maize in the Yazoo-Mississippi Delta

Authors: RIX, JACOB - Mississippi State University; LO, TSZ - Mississippi State University; GHOLSON, DREW - Mississippi State University; PRINGLE, H.C. - Mississippi State University; SPENCER, DAVE - Mississippi State University; SINGH, GURBIR - University Of Missouri

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2022
Publication Date: 9/15/2022
Citation: Rix, J.P., Lo, T.H., Gholson, D., Pringle, H.L., Spencer, D.G., Singh, G. 2022. Effects of low-till parabolic subsoiling frequency and furrow irrigation frequency on maize in the Yazoo-Mississippi Delta. Agricultural Water Management. 274:107945. https://doi.org/10.1016/j.agwat.2022.107945.
DOI: https://doi.org/10.1016/j.agwat.2022.107945

Interpretive Summary: Lighter-textured soils in the Yazoo-Mississippi Delta tend to be prone to compaction, surface sealing, and organic matter losses. Consequently, less water from rain and irrigation ends up soaking into the soil, which then encourages more frequent irrigation and greater groundwater depletion. This study showed that the amount of furrow irrigation water soaking into the soil could be increased by low-till parabolic subsoiling, which uses curved shanks to break up a diagonal zone from the furrow surface to about 15" beneath the raised bed. Performing this operation during the off-season before a corn crop could allow yield and profit to remain high and stable while reducing irrigation frequency. These findings suggest that low-till parabolic subsoiling before growing corn can help sustain both the water resources of the Delta and the bottom line of its farms. Such research-based recommendations can be considered by policymakers and farmers as they seek to make decisions that enhance the present and future wellbeing of Delta families and communities.

Technical Abstract: Naturally forming or mechanically induced hardpans limit water infiltration and crop productivity in many agricultural regions including the Mid-South U.S. This research was conducted to determine whether low-till parabolic subsoiling and furrow irrigation interact to influence soil water dynamics and maize production in the Mid-South. The factorial effects of subsoiling frequency (no subsoiling, NS; subsoiling only before cotton, CS; subsoiling only before maize, MS; and subsoiling every year, ES) × irrigation frequency (no irrigation, NI; low-frequency irrigation, LI; and high-frequency irrigation, HI) on infiltration, grain yield, and profit over specified costs were investigated for the maize portion of a maize-cotton rotation experiment in a silty clay loam soil near Tribbett, Mississippi. Subsoiling before maize improved the infiltration of irrigation (p < 0.05) but not the infiltration of in-season rainfall for irrigated treatments. By subsoiling before maize, high-frequency irrigation maximized grain yield in just one—rather than three—out of five years. Subsoiling before maize also increased non-irrigated yield in all five years. Overall, the combination of subsoiling only before maize and low-frequency irrigation achieved the largest average profit and a relatively small risk. These findings support the practice of low-till parabolic subsoiling before maize as a hydrologically effective and economically viable strategy to conserve freshwater resources in the Mid-South.