Short-term Disruption of Soil Physical and Biological Properties Caused by Land Leveling

The spatial variability and distributions of soil physical and biological properties, and the relationships between them, are not well-characterized in agroecosystems that have been land-leveled. The objectives of this study were to characterize the short-term impacts of land leveling on the magnitudes, spatial variability, and spatial distributions of soil physical and biological properties in a Stuttgart silt loam (fine, smectitic, thermic Albaqultic Hapludalf) used for irrigated soybean [Glycine max (L.) Merr.] and rice (Oryza sativa L.) production in the Mississippi Delta region of eastern Arkansas. Bulk density, and sand and clay contents, significantly increased while silt content and fungal and bacterial biomass significantly decreased as a result of land leveling. Land leveling significantly changed the variance associated with soil biological properties, but the variances of soil physical properties were unaffected. The spatial distributions of soil fungal and bacterial biomass in the top 10 cm were most noticeably altered by land leveling in comparison to pre-leveling distributions. These results indicate that variability in soil biological properties may play an important role in restoring productivity to precision-leveled soils.