Corn Growth and Yield as Affected by Surface and Subsoil Compaction

AbstractWheel traffic of harvesting operations on agricultural fields often carries compactive loads in excess of 8 Mg. Consequently, soil physical properties may be affected to depths of 60 cm, and these effects of compaction may persist for a number of years. In addition, smaller compactive forces that affect only the surface layer of soil are applied annually during spring tillage and planting operations. A replicated field study was conducted on a Webster clay loam (fine‐loamy, mixed, mesic Typic Haplaquolls) in southern Minnesota, and two Ves clay loams (fine‐loamy, mixed, mesic Udic Haplustolls) in southwestern Minnesota to assess the effects of surface and subsoil compaction on the growth and yield of corn (Zea mays L.). A total of six compaction treatments was imposed; subsoil compaction of control (no subsoil compaction), 9 Mg per axle, and 18 Mg per axle loads, each with and without annually applied interrow surface compaction of <4.5 Mg per axle. During the first year after high axle loading, 9 and 18 Mg per axle loads significantly decreased final grain yield by 9 and 30%, respectively, on the Webster soil. For the second year, the 18 Mg per axle treatment significantly reduced yield by 12% as compared with the control treatment. Soil water loss data indicated a more shallow rooting depth and/or reduced root activity in the 18 Mg per axle treatment. High axle loads on a dry Ves soil caused little subsoil compaction; grain yield was reduced by only 6% the first year after high axle loading. High axle loads on a relatively wet Ves soil compacted the soil to a depth of 60 cm. However, relatively dry climatic conditions the following year negated any potential adverse effects of subsoil compaction and yields were not affected. Surface layer compaction from annual interrow wheel traffic did not cause a significant yield response consistently at any site.