Effects of conservation practices on rainfed maize yield, furrow water infiltration, and soil moisture for surface sealing loam soils in the Yazoo-Mississippi Delta

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

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2023
Publication Date: 11/25/2023
Citation: Rix, J.P., Lo, T., Gholson, D.M., Spencer, D.G., Singh, G. 2023. Effects of conservation practices on rainfed maize yield, furrow water infiltration, and soil moisture for surface sealing loam soils in the Yazoo-Mississippi Delta. Soil Science Society of America Journal. https://doi.org/10.1002/saj2.20595.
DOI: https://doi.org/10.1002/saj2.20595

Interpretive Summary: In loam soils of the Lower Mississippi River Basin, surface sealing reduces the ability of the soil to soak in water from rain and irrigation. This problem decreases the profitability of non-irrigated farming and increases irrigation pumping from the Mississippi River Valley Alluvial Aquifer. Through a two-year plot experiment, the present study did not find evidence that surface sealing can be alleviated by subsoiling, by no-tillage, or by cereal rye cover cropping--despite these conservation practices having been implemented for at least two years even before the present study. Newly implemented practices including granular polyacrylamide application and furrow diking did not show clear advantages over conventional tillage either. With the accomplishment of obtaining these sobering results, the present study points out that commonly recommended conservation practices do not guarantee the lessening of surface sealing. The present study contributes to solving the problem by highlighting the need for optimizing the implementation of these practices or for developing other practices instead.

Technical Abstract: Decades of intense tillage have created the problem of surface sealing in loam soils across the Mid-South United States and beyond. These soils exhibit low organic matter, poor aggregate stability, and ultimately low infiltration rates that decrease rainfed crop productivity and increase irrigation water demand. This research quantified the effects of soil management practices on rainfed maize (Zea mays L.) yield, furrow water infiltration, and soil moisture in Commerce very fine sandy loam and silt loam near Stoneville, MS. The six treatments included conventional tillage (CT), cereal rye (CR; Secale cereale L.), furrow diking (FD), no-till (NT), polyacrylamide (PAM), and subsoiling (SS). No other treatment achieved a significantly higher maize grain yield than the CT control treatment in both years consistently. Single-ring infiltrometer results indicated no significant differences among CT, CR, PAM, and SS in 2022 and between CT and NT in 2021. Neutron attenuation found that total soil water within the top 1 m was not significantly different among CT, FD, and SS on any of the eight measurement dates throughout the 2022 maize reproductive period. However, soil moisture was numerically lower for FD in the late reproductive stages. These findings suggest that environmental factors and other agronomic operations may counteract conservation practices, limiting their effectiveness at reducing irrigation requirements to mitigate groundwater depletion in the Mississippi River Valley Alluvial Aquifer.