- Agronomic: cotton, sorghum (milo)
- Crop Production: cover crops, water management
- Pest Management: integrated pest management
Problem addressed: Cover crop systems are widely promoted for their potential benefits on weed suppression, water quality, nutrient cycling, among others. While cover crop systems have witnessed widespread adoption in the Northern parts of the country, adoption in places such as South Texas has been very limited. Some of the major limitations include lack of tools and knowledge to facilitate cover crop selection, insufficient biomass production prior to cash crop planting in spring and perceived soil moisture loss caused by cover crop growth. Addressing these limitations is critical to promote cover crop adoption in this region.
Research approach: A total of 26 summer and winter cover crop species were evaluated for their suitability for the Southeast Texas region. The summer covers were established during late August, following the harvest of corn/grain sorghum in the region, whereas the winter covers were established during mid-October, to fit production scenarios following a cotton crop. The experiments were conducted in a randomized complete block design with four replications. Cover crop seeding rates were determined based on production guides. Cover crop growth, biomass, decomposition rates, weed suppression and soil moisture dynamics were documented. Four best species selected from the initial experiment were then established at different planting timings (for summer covers) or termination timings (winter covers) prior to corn or cotton to evaluate the impact of cover crops on cash crop growth, weed suppression, soil moisture and crop yield.
Research conclusions: The experiments were vital in identifying cover crop species that are suitable for the Southeast Texas region in terms of fast growth and biomass production, high weed suppression, and limited impact on soil moisture. Sorghum-sudangrass, sunn hemp, cowpea and buckwheat were the top four summer cover crops, whereas triticale, oat, mustard and Austrian winter pea were the top winter cover crops. In the cash crops, terminated cover crop residues offered significant weed suppression benefits, even in circumstances where the cover crop biomass was low. Though cover crops extract soil moisture, moisture loss might not be a concern in this region due to soil moisture replenishment by spring rains. Overall, cash crop emergence and establishment were unaffected by the cover crops. Results also showed that some changes to crop management, such as appropriate fertilization and monitoring for insect/disease infestation on the seedlings, are imperative for achieving high yields when incorporating cover crops in the production system.
Adoption actions: Findings from this study were broadly communicated to farmers, crop consultants and scientific community. The knowledge generated from this experiment is expected to facilitate cover crop adoption in the region.
1. Evaluate the influence of warm-season cover crop growth on summer annual weed suppression and soil moisture demand;
2. Evaluate the impact of the late-summer cover crop planting timing on weed suppression, soil moisture dynamics and yield in corn;
3. Evaluate the influence of cool-season cover crop and biomass production on winter annual weed suppression and soil moisture demand;
4. Evaluate the impact of the fall cover crop termination timing on weed suppression, soil moisture dynamics and yield in cotton.