Soil Aggregate Stability as Affected by Landuse and Soil Properties in the Lower Mississippi River Valley

Abstract

Core Ideas Improving soil aggregation may promote infiltration. Soil aggregation properties differ by land use. Grassland and forest restoration may improve groundwater recharge. Improving soil aggregate stability, thus improving infiltration and reducing surface runoff and soil erosion, may lead to multiple environmental benefits in the Lower Mississippi River Valley (LMRV). The objective of this study was to evaluate the effects of common landuses (i.e., native prairie, deciduous forest, coniferous forest, Conservation Reserve Program [CRP] grassland, and conventional‐tillage [CT] and no‐tillage [NT] agriculture), aggregate‐size class, and soil depth on aggregate‐stability‐related properties on fine‐textured, loessial and alluvial soils in the Arkansas Delta region of the LMRV. Total water‐stable aggregate (TWSA) concentrations in the top 10 cm in the native prairie, CRP, and coniferous forest were similar (p > 0.05) to each other, averaging 806 g kg−1, and were 35% greater (p < 0.05) than that of the NT and CT agroecosystems, which did not differ and averaged 605 g kg−1. The mean weight diameter (MWD) in the top 10 cm in the native prairie, CRP, and coniferous forest was similar (p > 0.05) to each other, averaging 2.1 mm, and were 70% greater (p < 0.05) than that in the NT and CT agroecosystems, which did not differ and averaged 1.3 mm. In the top 5 cm, the MWD and TWSA concentration were 17 and 8% greater (p < 0.05), respectively, than that in the 5‐ to 10‐cm depth interval. Grassland and forest restoration, specifically of highly erodible agricultural land, should be considered to contribute to improvements in soil structural stability and the future sustainability of soil and water resources in the LMRV.