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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #420588
Research Project: Innovative Technologies and Practices to Enhance Water Quantity and Quality Management for Sustainable Agricultural Systems in the Southeastern Coastal Plain

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: Perennial goundcover crop effects on soil moisture retention and water use efficiency in cotton cropping systems

Author
item Billman, Eric
item STONE, KENNETH - Retired ARS Employee
item Paye, Wooiklee

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2025
Publication Date: 6/7/2025
Citation: Billman, E.D., Stone, K.C., Paye, W.S. 2025. Perennial goundcover crop effects on soil moisture retention and water use efficiency in cotton cropping systems. Agronomy Journal. 117(3). https://doi.org/10.1002/agj2.70094.
DOI: https://doi.org/10.1002/agj2.70094

Interpretive Summary: Traditional cover crop management in cotton production involves terminating annual cover crop species such as cereal rye, crimson clover, and hairy vetch approximately 4 – 6 weeks before planting cotton to conserve soil moisture and reduce the risk of drought stress to the cotton crop. However, soils of the Coastal Plain region are sandy and can only hold enough water to last 7 – 10 days before needing additional rainfall or irrigation, and most cover crop species only draw water from the upper 6 – 12 inches of soil. Therefore, new management strategies focused on perennial cover crops may allow cotton to be grown while perennial cover crops persist between the rows. These perennial covers could insulate the soil and reduce evaporative water losses in hot and dry weather common to the southern U.S. while also reducing the rate and frequency of pesticides needed to control weed and insect pests. A two-year study was conducted by USDA-ARS research scientists at the Coastal Plains Soil, Water, and Plant Research Center in Florence, South Carolina to determine the effects of growing perennial cover crops such as white clover and red clover on soil water availability, drought stress, and water use efficiency when grown alongside cotton. This research found that more water was consistently present in the upper 6-inches and lower 18-inches of soil, but that soils were drier at the 12-inch depth where perennial cover crops were grown. These effects were likely due to changes in cotton rooting depth, as cotton will root deeper to access necessary soil water. Thus, cotton likely had shallower roots when perennial cover crops were grown due to increased soil water content. Additionally, cotton plants did not experience increased drought stress or reduced water use efficiency when growing perennial clovers alongside them. These findings suggest that perennial cover crops such as red and white clover that aid in weed suppression and provide feed for livestock can be grown alongside cotton without depleting soil water reserves or increasing cotton drought stress.

Technical Abstract: Cotton (Gossypium hirsutum L.) production in the U.S. southeastern Coastal Plain is frequently affected by periods of limited water availability. Perennial groundcover crops (PGCC) could aid in conserving soil moisture while reducing additional input costs to manage cotton. This study evaluated the effects of PGCC species red clover (Trifolium pratense L.) and white clover (Trifolium repens L.) on soil moisture retention and electrical conductivity (EC), and on cotton crop drought stress and water use efficiency compared to paradigms of weedy fallow and a terminated annual cover crop. Plots were strip tilled and planted with cotton in May of each year with clovers remaining alive between rows year-round. Results showed that soils with PGCC had greater volumetric water content (VWC) and EC than soil grown with annual cover crops at 15-cm (0.10 – 0.18 m3m-3 and 15 – 40 µS cm-1) and 45-cm (0.21 – 0.33 m3m-3 and 73 – 190 µS cm-1) depths, but less at 30-cm (0.16 – 0.21 m3m-3 and 28 – 82 µS cm-1). Additionally, cotton leaf water potential (-12 to -23 Bar) and seedcotton (1.6 – 2.77 kg mm-1) and lint (0.74 – 1.22 kg mm-1) water use efficiencies did not differ among treatments. However, cover crop biomass moisture concentrations were negatively correlated (-0.71) to seedcotton and lint water use efficiencies during a wet growing season. These findings indicated that perennial clovers could be grown alongside cotton to provide ecosystem service benefits without reducing cotton crop access to limited water resources.