Cover crops and poultry litter impact on soil structural stability in dryland soil of Southeastern United States

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: Journal of Cleaner Production
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2024
Publication Date: 4/29/2024
Citation: Dai, W., Feng, G.G., Huang, Y., Tewolde, H., Shankle, M., Jenkins, J.N. 2024. Cover crops and poultry litter impact on soil structural stability in dryland soil of Southeastern United States. Journal of Cleaner Production. 88:1449-1462. https://doi.org/10.1002/saj2.20676.
DOI: https://doi.org/10.1002/saj2.20676

Interpretive Summary: Soil structure plays an important role in mediating soil ecological functions and regulating both soil physical, chemical, and biological processes. Soil aggregates, naturally formed by the forces of adhesion and cohesion, serve as the fundamental units of soil structure, facilitating the clustering and aggregation of soil particles alongside organic matter and inorganic minerals. The stability of soil structure, as well as its capacity to support ecosystem functions and contribute to climate change mitigation, is closely linked to soil aggregate stability. The assessment of soil aggregate stability is essential for the evaluation of soil structural quality, water and nutrient transport, and the potential for soil erosion. This manuscript studied the combined effects of cover crops and poultry litter in dryland soil on soil aggregation and structural stability. The results showed that the R and PL exhibited the highest values for ASI. The highest MWD and GMD were found under M+R and R, respectively. The FD was highest in V, followed by NV. Similarly, FD was highest in Fert, followed by PL. The PCA displayed clear effects of different cover crops on aggregate structure and stability, indicating that cover crops can compensate for the shortcomings of fertilizer alone in enhancing soil structure stability. ASI, MWD, and GMD were positively correlated with SOC, FD was negatively correlated with MWD, GWD, and ASI. The PCA revealed that FD decreased with increasing SOC, ASI, MWD, and GMD, suggesting that lower FD values indicate promote soil aggregation and structure. This study will provide meaningful information for future research in the field of soil aggregation around the world, contributing to the sustainability of soil productivity and agriculture.

Technical Abstract: Soil structure regulates soil function and can be impacted by agricultural management practices such as no-till, cover crops, and organic fertilizer use. This study explored the efficacy of multiple soil aggregate indices in quantifying soil structural development, utilizing five-year field experiment data from southeastern United States. The experiment had a split-plot design with cover crops [native vegetation (control), cereal rye (Secale cereale; R), winter wheat (Triticum aestivum; W), hairy vetch (Vicia villosa; V), and mustard (Brassica rapa) plus cereal rye (M+R)] as the main factor and with fertilizer source [no fertilizer (control), inorganic fertilizer (phosphorus, potassium, and elemental sulfur; Fert), and poultry litter (PL)] as the second factor. Aggregate size fractions were obtained using the wet-sieving method in the laboratory, and aggregate stability index (ASI), mean weight diameter (MWD), geometric mean diameter (GMD), and fractal dimension (FD) were calculated to assess soil aggregation using linear regression and principal component analysis (PCA). Across all combined treatments, the R (55.11%) and PL (50.97%) exhibited the highest values for ASI. The highest MWD and GMD were found under M+R (1.187 mm) and R (0.462 mm), respectively. The FD was highest (2.573) in V, followed by NV, W, M+R, and R (2.571, 2.163, 2.098, and 2.049, respectively). Similarly, FD was highest (2.418) in Fert, followed by PL (2.305) and control (2.149). The PCA displayed clear effects of different cover crops on aggregate structure and stability, indicating that cover crops can compensate for the fertilization practices alone in enhancing soil structure stability. The result of linear regression showed that ASI, MWD, and GMD were positively correlated with SOC, suggesting an increase in ASI, MWD, and GMD associated with increasing SOC. FD was negatively correlated with MWD, GWD, and ASI. Also, the PCA revealed that FD decreased with increasing SOC, ASI, MWD, and GMD, suggesting that lower FD values indicate enhanced soil aggregation and structure. Collectively, the assessed indices, FD included, prove effective in gauging soil aggregation and structural stability. These metrics should be given additional consideration in managerial decisions to support soil productivity and agricultural sustainability.