Long‐Term Conventional and No‐Tillage Effects on Selected Soil Physical Properties

Abstract Soil management systems can affect soil physical properties and, thus, have a direct bearing on crop performance. This study determined the effects of continuous long‐term conventional and no‐tillage management on selected soil physical properties and compared observed yield differences between these tillage systems with soil physical properties. Three Maryland locations, each having randomized complete‐block designs with three replications of continuous corn ( Zea mays L.) under conventional and no‐tillage management, were used. Sites 1 and 2 were in their 12th yr of tillage and Site 3 was in its 11th yr. Soils at all three sites were silt loams (fine‐loamy, mixed, Aquic Hapludults). Tillage affected bulk density at the 0.05 level at Site 1 and the 0.10 level at Site 2. No‐tilled soils generally had higher bulk density at all soil depths for Sites 1 and 2. Tillage affected soil strength at Sites 1 and 2, but not at Site 3. Soil strength for no‐tilled soils was consistently greater than for conventionally tilled soils. Conventionally tilled soils had greater pore volume in pores with radii >15 µm at Sites 1 and 2, and, therefore, should drain more readily than no‐tilled soils. More importantly, the amount of pore space available for the storage of plant‐available water was greater for conventionally‐tilled soils at Sites 1 and 2. Although soil physical properties within the Ap horizon are not adequate to account for differences in corn yield response, tillage differences in soil physical properties were found for the soils at Sites 1 and 2, which had previously shown tillage yield differences.