|ZHOU, XIA - University Of Tennessee|
|LARSON, JAMES - University Of Tennessee|
|SYKES, VIRGINIA - University Of Tennessee|
|ALLEN, FRED - University Of Tennessee|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/27/2022
Publication Date: 2/17/2022
Citation: Zhou, X., Larson, J., Sykes, V., Ashworth, A.J., Allen, F.L. 2022. Long-term conservation agriculture effects on corn profitability in West Tennessee. Crop Science. 62:1348-1359. https://doi.org/10.1002/csc2.20727.
Interpretive Summary: Crop rotations and cover crops may enhance crop yields and improve soil health, however, producers may be reluctant to adopt these conservation practices because of uncertain economic returns associated with adoption of these practices. This study set out to identify the profitability of corn rotated with cotton and soybean cash crops, as well as cover crops (hairy vetch and winter wheat), and poultry litter (subsequent winter weed growth emulating a cover crop). Corn yields were collected from 2002 to 2017 and net returns (gross income minus expenses) were calculated for each corn-rotation combination within 4-year phases. Researchers found that over the 16-yr period, rotations of corn with soybean and cotton improved grain yields and net returns, but only in the last 4-years of the study; however, averaged across 16-years, corn in rotation with soybean and/or cotton did not improve yields and net returns. Vetch cover crops resulted in greater corn grain yields, whereas wheat cover crops were the lowest, with fallow corn resulting in the greatest net returns than any cover crop or poultry litter application. Consequently, crop rotations and cover crop costs would need monetary conservation incentives for producers in order to make these best management practices economically feasible.
Technical Abstract: Crop rotations, cover crops, and poultry litter (PL) under no tillage (NT) may improve soil health and crop yields. However, whether farmers adopt those practices depends on profitability. This study evaluated profitability of NT corn (Zea mays L.) in monoculture versus rotations with soybean (Glycine max L.) and cotton (Gossypium hirsutum L.) with/without cover crops and PL from 2002 through 2017 in Tennessee. Whole-block treatments were 10 crop rotations, each repeated in 4-yr cycles (Phases). Split-block treatments were fallow versus PL applications and hairy vetch (Vicia villosa L.) and winter wheat (Triticum aestivum L.) cover crops. Corn yield and net return (NR) differences occurred by Phase, cover crops and PL application, and rotations. Rotation interacted with Phase to influence corn grain yield and NRs, with positive rotation effects occurring in Phase IV. Phase individually influenced yields and NRs, with the greatest occurring in Phase IV, and lowest in Phase III. Cover crops and PL influenced yields and NRs over 16 years. Vetch cover resulted in greatest corn grain yields, whereas wheat cover were the lowest. However, fallow corn resulted in the greatest NRs than any cover crop or PL application. Specifically, PL, hairy vetch, and wheat costs should be decreased by 71, 68, and 100%, respectively, to achieve equivalent NRs to fallow corn systems. Increased revenue from enhanced yields or fertilizer savings from covers or PL did not offset establishment costs. Therefore, farmers may need incentives to adopt conservation agricultural practices.