Cover crop and minimum tillage effects on yield, irrigation water use, and net returns

Abstract

The addition of cover crops and minimum tillage to current row‐crop production practices in the mid‐southern United States could holistically improve the sustainability of these farming systems. This relatively short‐term study was conducted to determine if the addition of these practices into corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotational systems in the region would decrease irrigation water use while improving yield, irrigation water use efficiency, and net returns above production costs. The effects of cover crops and minimum tillage on these parameters were investigated from 2017 to 2019 on six pairs of production fields in northwest Mississippi. A pair was created by dividing a single field that had been under uniform management into two fields that were land leveled and hydrologically separated with an earthen berm. Control fields were managed according to standard practices within the region, which include winter fallow and multiple tillage passes, whereas treatment fields were managed with winter cover crops and minimum tillage. The addition of cover crops and minimum tillage had no effect on yield (p = .09), irrigation water use efficiency (p = .38), or irrigation water applied (p = .83). The net economic return on average across all site years was a loss of US$233 ha–1. These results reflect the short study period as changes resulting from these practices often occur on a greater time scale. The value proposition for adoption of a cover crop–minimum tillage system will be challenging in the mid‐southern United States if potential benefits are to be expected in the early years of adoption.

Corn productivity and profitability in raised stale seedbed systems with and without cover crops

“…Conversely, in the humid, subtropical mid‐southern and southeastern United States, cover crops had no effect or decreased WUE by 11% in corn, cotton, and soybean [Glycine max (L.) Merr.] (Badon et al., 2021; Bryant et al., 2020a, 2020b; Meeks et al., 2020). Our data support these findings showing that cover crops do not improve cash crop WUE in the mid‐southern United States.…”

“…Conversely, in the humid, subtropical midsouthern and southeastern United States, cover crops had no effect or decreased WUE by 11% in corn, cotton, and soybean [Glycine max (L.) Merr.] (Badon et al, 2021;Bryant et al, 2020aBryant et al, , 2020bMeeks et al, 2020). Our data support F I G U R E 1 Cumulative precipitation relative to 30-yr norms in Stoneville, MS, for each year of an experiment that investigated the effect of cover crops in a raised stale seedbed system on a Commerce very fine sandy loam (fine-silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquept) during the 2017 to 2020 cropping seasons these findings showing that cover crops do not improve cash crop WUE in the mid-southern United States.…”

“…A meta‐analysis of corn's yield response to winter cover crops demonstrated that grass cover crops have no effect on yield across N fertilization levels, and leguminous cover crops do not affect yield when >178 lb N acre −1 is applied (Marcillo & Miguez, 2017). In raised stale seedbed systems in the mid‐southern United States, cover crops occasionally improve yield but predominantly have no effect (Badon et al., 2021; Koger & Reddy, 2005). The lack of a consistent yield increase under cover crops may suggest that N availability from cover crops is not synchronized with corn's N requirements.…”

Contrasting effects of agroecosystem biocrusts on seedling growth and nitrogen accumulation in a greenhouse environment

“…Legume cover crops commonly have lower C:N ratios and release N more quickly than grasses and other nonleguminous cover crops, increasing the potential for mineralization of the residue to supply N for a primary crop after cover crop termination (Aiosa et al, 2020;Nevins et al, 2020aNevins et al, , 2021b. Negative effects of cover crops on primary crop growth and yield have also been observed (Badon et al, 2021). These have been attributed to allelopathic effects that stunt plant growth (Weston, 1996) and increase competition for N with microorganisms during cover crop decomposition (Uchino et al, 2009).…”

Agronomic and economic implications of cover crop and phosphorus fertilizer management practices for water quality improvement

“…Badon et al. (2021) found no yield or irrigation differences for adoption of a CC and minimum tillage system, but they did find additional costs from these practices resulted in lower net returns that would have to be offset by non‐monetary benefits or incentives to encourage producers to adopt a CC system. Potential water quality benefits to society arising from CC implementation may justify financial incentives to encourage CC use.…”