Variability of soil physical quality and erodibility in a water-eroded cropland

Physical degradation of the soil increases its susceptibility to erosion by water action. However, relatively few studies have evaluated the opposite, i.e., the impact of water erosion on soil erodibility. This study was conducted in a corn field in Ohio. Some sites within the field have experienced water-induced soil erosion following heavy rainstorms. Physical characteristics of the soil were compared between eroded (ER) and un-eroded sites (UN). Compared with ER, the soil in UN had lower penetration resistance (4.87 vs. 4.53 MPa), bulk density (1.45 vs. 1.33 Mg m−3), and sand content (17.4 vs. 14.2%), and higher shear strength (80.1 vs. 125.3 KPa), hydraulic conductivity (3.0 vs. 3.4 cm h−1), intrinsic permeability (31.9 vs. 36.4 × 10−10 cm2), and contents of soil organic carbon (36.1 vs. 32.1 g kg−1), total nitrogen (3.3 vs. 3.1 g kg−1), clay (25.2 vs. 24.2%), silt (60.5 vs. 58.4%), and very fine sand (3.4 vs. 1.1%). Also Munsellʹs variables differed between ER and UN (1.24 vs. 0.54 for hue, 4.59 vs. 4.35 for value, and 1.99 vs. 1.79 for chroma, respectively). The erodibility factor (K) was lower in UN than in ER (0.00327 vs. 0.00354 Mg ha h ha−1 MJ−1 mm−1, respectively). Hence, it is suggested the ER sites within the corn field agroecosystem are more susceptible to accelerated erosion as compared with UN sites.