Use of Conservation Practices for Corn Production in the Midsouth
Even though this is a soybean website, other crops such as corn that are often rotated with soybean in the Midsouth deserve attention on this site. Thus, this article presents findings from research with corn grown with conservation agriculture practices in the Midsouth since the information is of value to soybean producers who may be considering how best to use corn in a rotation system with soybean.
As crop producers in the Midsouth know, conservation agriculture practices are being promoted for reducing the perceived negative impacts of high-input production of crops such as corn. The following two articles provide information about using these practices in a corn production system.
An article titled “Corn productivity and profitability in raised stale seedbed systems with and without cover crops” by Spencer et al. appears in the journal Crop Forage & Turfgrass Mgmt. 2022;8:e20142. Pertinent points from this article are provided.
• The objective of the research reported in this article was to determine if cover crops will cost-effectively improve the productivity and water use of corn grown in a raised stale seedbed system in the midsouthern U.S.
• The effects of cover crops–Austrian winter pea, crimson clover, cereal rye, and tillage radish–on grain yield, net returns, and water use efficiency (WUE) of corn grown on a fine sandy loam soil at Stoneville, Miss. were investigated.
• Experiments were conducted during the 2017-2020 growing seasons, and all treatments were managed in a reduced tillage system with corn planted on a raised stale seedbed.
• Irrigation was applied by the furrow method through polyethylene tubing when the weighted average soil water potential in the effective rooting zone reached -85 cbar. Four inches of water was applied at each irrigation.
• WUE was calculated as corn grain yield/total water from rain plus irrigation. Including a cover crop in this system never improved WUE.
• Results from this multi-year study indicated that cover crops can adversely affect corn grain yield in the first year of their use, with no improvement in yield in subsequent years up to 4 years after establishment. This lack of a corn yield increase with cover crops suggests that nitrogen (N) availability from cover crops is not synchronized with corn’s N requirement.
• Incorporating any of the four cover crops into a production system where corn is planted and grown on a raised stale seedbed reduced net returns below those from winter fallow. This was attributed to cover crops’ seed and seeding costs, herbicide costs associated with cover crop termination, corn yield reductions, and irrigation costs.
• The results from this study suggest that improved profitability from incorporating cover crops into a corn production system is not yet attainable.
• The authors concluded from these results that incorporating cover crops into a corn production system in the Midsouth should not be a blanket recommendation since they provided no measurable benefits in this short-term study.
An article titled “Long-Term Conservation Agriculture Effect on Corn Profitability in West Tennessee“ by Zhou et al. will soon be published in the journal Crop Sci. Pertinent points from this article follow.
• The objective of the research reported in this article was to evaluate the long-term effects of crop rotations with and without cover crops and poultry litter (PL) application on yields and profitability of No-Till (NT) corn production systems in West Tenn.
• NT corn yield data were collected for 16 years (2002-2017) from research plots on a Loring silt loam site at the Univ. of Tenn. Milan Res. and Educ. Center in Milan, Tenn.
• There was a total of 13 separate 4-year cropping systems that included corn, cotton, and soybean. Continuous corn was used as the control.
• Hairy vetch, winter wheat, Austrian winter pea, PL, and no cover were considered bio-cover treatments. All of the bio-cover treatments were terminated with herbicides each year.
• Results from this study indicated the following. 1) Corn grown in rotation with soybean and/or cotton did not influence either yields or net returns (NR) over the 16 years of the study. However, in the fourth phase of the study (years 13-16, 2014-2017), there was a positive rotation effect on both corn yields and NR’s when both soybean and cotton were rotated with corn. Thus, crop rotation used as a conservation compliance tool for NT corn production in this region likely should be applied over a long term for positive effects from its use to finally be realized. 2) Averaged over the 16 years of this long-term study, corn NR’s from the no-cover plots were the highest. 3) Use of winter cover crops and PL in this study was not profitable due to no increase in corn yield where they were used coupled with the costs associated with their use (PL–acquisition, transportation, and application; cover crops–seed, planting, and termination).
• The authors concluded from their results that subsidy incentive programs will likely be needed to encourage producers to adopt cover crops as a conservation production practice since these results indicate that they provide no profit incentive for NT corn production over the long term.
Take Home Message. Results from these studies indicate the following pertaining to use of cover crops with corn production systems in the Midsouth. 1) Short-term corn yield and NR increases likely will not be realized when cover crops are used. 2) Over the long term, it appears that producer use of cover crops may have to be encouraged by some sort of financial incentive program to offset the likely lower cropping system net returns when they are used.
Click here to access a White Paper that presents a thorough treatment of cover crops use in soybean production systems, and here to access a White Paper that presents information about using crop rotation in soybean production systems.
Composed by Larry G. Heatherly, Apr. 2022, larryh91746@gmail.com