Soil aggregate stability and erosion resistance in response to integration of cover crops and poultry litter in a no-till rainfed soybean cropping system

Authors: DAI, WEI - Oak Ridge Institute For Science And Education (ORISE); Feng, Gary; Huang, Yanbo; Tewolde, Haile; SHANKLE, MARK - Mississippi State University; Jenkins, Johnie

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2024
Publication Date: 7/24/2024
Citation: Dai, W., Feng, G.G., Huang, Y., Tewolde, H., Shankle, M.W., Jenkins, J.N. 2024. Soil aggregate stability and erosion resistance in response to integration of cover crops and poultry litter in a no-till rainfed soybean cropping system. Soil & Tillage Research. 244(2024):106245. https://doi.org/10.1016/j.still.2024.106245.
DOI: https://doi.org/10.1016/j.still.2024.106245

Interpretive Summary: Soil plays a key role in human survival and development, ensuring the long-term sustainability of soil resources is thereby essential for the future of humanity. Soil aggregates, as the fundamental units of soil structure, are intricately associated with soil bulk density, total soil porosity, water retention, soil microorganisms, soil erosion, and soil fertility. Consequently, they are acknowledged as apt indicators of soil productivity and health. The use of cover crops and poultry litter as a management practice has been adopted in many agricultural systems. Previous studies have reported that the use of cover crops and the addition of fertilizer as part of an agricultural system may improve soil properties. There has been a scarcity of research conducted in rainfed agriculture systems that has addressed the necessity to explore the combined impact of cover crops and fertilizer sources, such as poultry litter manure, on soil aggregate stability. Specifically, there is a lack of comprehensive understanding regarding the underlying mechanisms that govern the relationship between soil aggregate stability and soil erosion resistance, particularly in the context of cover crops and poultry litter manure. This manuscript studied the impact of the integration of cover crops and poultry litter manure application on soil aggregate stability and erosion resistance at depths of 0-5 cm and 5-10 cm in a rainfed agriculture system in Mississippi. The results showed that the 0.25-0.053 mm fraction predominated across all treatments and soil depths, followed by the 0.5-0.25 mm fraction, with the 2-1 mm fraction representing the smallest proportion. The cereal rye and mustard plus cereal rye cover crops exhibited the highest soil aggregate stability index and mean weight. diameter, respectively. The use of poultry litter resulted in the highest values for aggregate stability index, mean weight diameter, mean weight specific surface area, and fractal dimension. Furthermore, the mustard plus cereal rye cover crop displayed the lowest soil erodibility factor K. Soil erodibility factor K exhibited a positive correlation with mean weight specific surface area and fractal dimension and a negative correlation with aggregate stability index and mean weight diameter. The primary predictors of soil erodibility factor K were observed to be mean weight specific surface area, fractal dimension, and mean weight diameter. Overall, the integration of cover crops, such as cereal rye and mustard plus cereal rye, along with poultry litter, proved beneficial for improving the stability of soil aggregates. Consequently, this approach contributed to increased soil anti-erosion ability and soil health in rainfed agriculture systems.

Technical Abstract: Soil aggregate stability plays a crucial role in influencing erodibility and soil health. This study explored the integration of cover crops and poultry litter effects on soil aggregate stability and erosion resistance in a rainfed agriculture system. A five-year field experiment was conducted in an upland no-till soil near Pontotoc, Mississippi in which soybean was grown every year following five winter cover crops [native vegetation as control, cereal rye (Secale cereale L.), winter wheat (Triticum aestivum), hairy vetch (Vicia villosa), and mustard (Brassica rapa) plus cereal rye] and three fertilizer source (no fertilizer as control, recommended inorganic fertilizers, and poultry litter) in a split-plot design. Soil aggregate stability indicators including soil aggregate stability index, mean weight diameter, mean weight specific surface area, and fractal dimension, along with the erodibility factor K were measured at the conclusion of the study from soil samples from 0-5 cm and 5-10 cm soil depths following wet-sieving into five different sizes of aggregates (> 2 mm, 2-1 mm, 1-0.5 mm, 0.5-0.25 mm, and 0.25-0.053 mm). The results exhibited that the 0.25-0.053 mm fraction was the most prevalent among all treatments and soil depths while the 2-1 mm fraction represented the smallest proportion. The highest soil aggregate stability index of 60.2% was observed under cereal rye and the highest mean weight diameter of 1.616 mm was observed under mustard plus cereal rye. Among the fertilizer sources, the highest values of soil aggregate stability index, mean weight diameter, mean weight specific surface area, and fractal dimension (55.41%, 1.204 mm, 11.48 cm2 g-1, and 2.56, respectively) were obtained under poultry litter. The mustard plus cereal rye displayed the lowest soil erodibility factor K (0.081). Soil erodibility factor K correlated positively with mean weight specific surface area and fractal dimension and negatively with aggregate stability index and mean weight diameter. Random forest modeling and path analysis identified mean weight specific surface area, fractal dimension, and mean weight diameter as the dominant predictors of the soil erodibility factor K. Overall, the results highlighted that integrating cover crops, such as cereal rye and mustard plus cereal rye, along with poultry litter, can enhance soil aggregate stability, and this improvement contributed to increased soil erosion resistance and soil health in rainfed agriculture systems in the southeastern USA.