Information for Cover Crops Users
The following articles contain information that should be helpful to those producers who are using/plan to use cover crops [CC] in their crop production systems.
An article titled “Cover crops and P-fertilizer management affect microbial activity in a US Midwest corn and soybean rotation” by Starr et al. provides the following information.
• Results are from a study that was conducted near Manhattan, Kansas on a site with loam soils that had been in a continuous no-till corn-soybean rotation since the fall of 2014.
• CC treatments consisted of triticale and rapeseed, winter wheat and rapeseed, and no CC.
• Phosphorus [P] fertilizer treatments were either fall- or spring-applied P and no P fertilizer addition.
• Microbial biomass P was increased by P fertilizer addition, and this increased the P supply in the soil solution.
• These results indicate that P fertilizer addition and CC’s can interact with the soil microbial population to alter P cycling in the soil. This interaction could increase the risk of P runoff loss from a site that has a CC.
“Economic implications of reduced tillage and cover crops in the irrigated mid-South” is an article by Roberts et al. that provides the following points.
• Results are from a study that was conducted at Stoneville, Miss. on a site with predominantly silt loam and sandy loam soil textures.
• The site was irrigated by the furrow method using flat polyurethane tubing.
• Treatments included a control [fall subsoil (SS), winter fallow (WF), disking, bedding], no seedbed tillage with a winter fallow [NT–WF], and a CC treatment that was a fall-established cereal rye and hairy vetch mix.
• Treatments with a CC had higher variability and lower returns because of lower yields and increased expenses associated with the inclusion of the CC. However, including the CC reduced irrigation costs.
• The authors concluded that use of CC’s in the Midsouth will likely depend on the improvement of profitability associated with their use, which will entail determining agronomic practices that will increase the yield of following crops and reducing costs associated with CC use.
An article titled “Cover crops, double-crop soybean, and nitrogen rates affect productivity and profitability of a no-till rotation” by Yeager et al. reports results from a dryland study that was conducted near Manhattan, Kansas on a site with a silty clay loam soil. Pertinent points from that study follow.
• Intensifying a no-till sorghum-soybean-wheat rotation with CC’s can potentially increase system productivity and profits.
• The amount of nitrogen [N] fertilizer applied to sorghum was affected by the type of CC–i.e. a high vs. low carbon to N ratio CC–that was used.
• The authors concluded that cropping system intensification must be managed carefully to achieve positive economic outcomes in a production system that uses CC’s.
An article titled “Study develops optimal cover crop adoption thresholds” by Kulikowski provides results from 35 years of data obtained from a West Tenn. farm that can be used to suggest conditions for using CC’s.
• The model can be used to suggest whether or not the inclusion of a CC will be economically beneficial depending on prices of cash crops and fertilizer inputs, as well as the health and inherent fertility of the soil at a production site.
• The model estimates imply significant effects of CC’s on yield of a following crop, as well as substitution effects between CC’s and N fertilizer inputs.
• The model suggests a threshold level of soil fertility, above which it is optimal to adopt CC’s and below which it is not.
• Adoption of CC’s is more favored if no-till practices are used.
• The model results indicate that CC adoption in no-till systems can lead to significant fertilizer cost savings when fertilizer costs are high.
• Detailed results of this research can be found in an article titled Dynamically optimal cover crop adoption that appears in the European Review of Agricultural Economics journal.
Information in the above-cited articles further reinforces that 1) CC adoption will not likely increase net returns in the short term, even though costs of some inputs may be lower when CC’s are used, and 2) incentive payments will likely be required to encourage CC use in agricultural production systems in the Midsouth.
Composed by Larry G. Heatherly, June 2025, larryh91746@gmail.com