Impact of cover crop management in a corn-cotton cropping system on soil aggregate stability and related factors

Authors: DAI, WEI - Oak Ridge Institute For Science And Education (ORISE); Feng, Gary; Huang, Yanbo; Adeli, Ardeshir; Jenkins, Johnie

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2024
Publication Date: 6/25/2024
Citation: Dai, W., Feng, G.G., Huang, Y., Adeli, A., Jenkins, J.N. 2024. Impact of cover crop management in a corn-cotton cropping system on soil aggregate stability and related factors. Soil & Tillage Research. 244(2024):106197. https://doi.org/10.1016/j.still.2024.106197.
DOI: https://doi.org/10.1016/j.still.2024.106197

Interpretive Summary: Soil aggregate stability is a crucial indicator of soil structure and its vulnerability to erosion, as well as its potential for infiltration. Cover crops can play an important role in soil conservation and enhance the sustainability of agricultural systems.Planting a winter cover crop has been shown to add organic matter, augment soil fertility, enhance soil tilth, and improve plant diversity and pollinator resources. Some studies have been reported that the addition of cover crops increased the content of SOC, decreased soil bulk density, and enhanced water-stable aggregates stability as compared to plots without cover crops. However, the extent of impact and the underlying mechanisms of cover crops on soil aggregates are infrequently assessed. Furthermore, there is a need to elucidate the stability of soil aggregates and the factors (e.g., SOC) that influence it after implementing cover crop management practices in agricultural systems. This manuscript studied the impact of different cover crops on soil aggregate stability indices in Marietta silt loam upland soil within a corn-cotton cropping system, as well as their relationship with environmental factors. The results showed that the peas and rye cover crop treatments had positive effects on soil aggregate stability such as MWD and WSA > 0.25. The MWD, WSA > 0.25, and K factor were significantly correlated with soil physiochemical properties. The dominant factors driving changes in the three stability indices were found to be pH and BD. In sum, these findings indicated that the cover crop management practices were favored for the improvement of soil aggregates, and helped us better understand the relationship between soil aggregates and environmental factors in the corn-cotton cropping system.

Technical Abstract: Soil aggregate stability has a positive influence on improving soil porosity, water holding capacity, permeability, and reducing soil erosion. We investigated the effects of various cover crops on soil aggregate stability indices [mean weight diameter (MWD, mm), water-stable aggregates greater than 0.25 mm (WSA > 0.25, %), and soil erodibility factor (K factor)] and their relationship to environmental factors in Marietta silt loam upland soil under a corn-cotton cropping system. A field experiment was conducted from 2019 through 2022 in the R. R. Foil Plant Science Research Center, Northeastern Mississippi with the cover crop treatments including elbon rye (Secale cereale L.), daikon radish (Raphanus sativus ssp. acanthiformis), Austrian winter field peas (Lathyrus hirsutus), and a mixture of the three-cover crop species. Soil samples were collected from depths of 0-5 cm and 5-10 cm in the spring of 2022 after planting three years of those cover crops. The samples were wet-sieved to five classes of aggregates with different sizes (> 2, 2-1, 1-0.5, 0.5-0.25, and < 0.25 mm). The values of MWD, WSA > 0.25, and K factor at 0-10 cm depth ranged from 0.26 to 0.58 mm, 21.98 to 49.05%, and 0.13 to 0.18, respectively, in all treatments. Among cover crops selected for this study, rye displayed the greatest values for MWD (0.58 mm) across all treatments and soil depths. The WSA > 0.25 value of peas was significantly (p < 0.05) higher by 68.61% compared to the no cover crop treatments at 0-5 cm depth, while the K factor did not change significantly. The MWD, WSA > 0.25, and K factor were significantly (p < 0.05) correlated with soil organic carbon, pH, bulk density, phosphorus, potassium, and calcium. The dominant factors driving changes in these stability indices were pH and bulk density. Overall, these results suggested that cover crops, such as rye and peas, were beneficial to the stability of soil aggregates. This study provided a basis for understanding the mechanisms of soil stabilization in crop management systems.