Influence of Cover Crop and Wheel Traffic on Soil Physical Properties in Continuous No‐Till Corn

Abstract

AbstractConservation tillage systems utilizing winter annual cover crops represent a different soil physical environment compared to conventional tillage systems. A field experiment was conducted for 3 yr on a Goldsboro fine sandy loam (fine‐loamy, siliceous, thermic Aquic Paleudults) in the North Carolina Coastal Plain to assess effects of cover crop type and row position on soil physical properties under no‐tillage corn (Zea mays L.) management. Bulk density (ρb), soil porosity, and hydraulic conductivity (Ksat) were measured in fallow, winter wheat (Triticum aestivum L.), and hairy vetch (Vicia villosa Roth.) systems with respect to three row positions (trafficked, untrafficked, and plant row). All traffic was controlled such that each corn row was bordered by a trafficked and untrafficked interrow. In general, soil physical properties were unaffected by cover crop type but strongly influenced by position. Bulk density was significantly higher in the trafficked vs. untrafficked position (1.74 vs. 1.52 Mg m−3) after 3 yr and tended to increase with time in the trafficked interrow. Associated with higher ρb values in the trafficked interrow were significantly lower values for soil porosity and Ksat. Total porosity in the trafficked position, averaged over cover crop type and 3 yr, decreased 21% below that of the untrafficked position. After 3 yr, Ksat was 0.019 and 0.002 mm s−1 in untrafficked and trafficked interrows, respectively. These results suggest that controlled traffic patterns may be an important component in the management of continuous, conservation tillage systems.