Zone Tillage Impacts on Organic Carbon of a Clay Loam in Southwestern Ontario

Abstract

No-till (NT) management can reduce corn (Zea mays L.) yields relative to moldboard plow tillage (MP) on fine-textured soils in cool humid climates. Zone tillage (ZT) consists of tilling the corn row only (zone in, ZI) and leaving the interrows uncultivated (zone out, ZO) and has increased corn yields relative to NT. In this study, soil organic C (SOC) content, bulk density, and penetration resistance were compared among ZT, ZI, ZO, MP, and NT for a Brookston clay loam soil (Typic Argiaquoll) in southern Ontario, Canada. Relative to MP, NT produced SOC stratification, with significantly greater SOC in the surface soil (0-5 cm) but lower SOC in the subsurface soil (10-30 cm). Zone tillage produced SOC and total soil N levels that were similar to NT near the soil surface but similar to MP in the subsurface. On an equivalent soil mass basis (4570 Mg ha ―1 ), ZT increased SOC storage (80.6 Mg C ha ―1 ) by 11.2 and 12.5% compared with NT and MP, respectively. Penetration resistance and bulk density at the 0- to 20-cm depth were lower in ZI than the other tillage treatments. Soil moisture content at the 0- to 12-cm depth under ZO was similar to NT and both were greater than ZI and MP. Zone tillage did not reduce stratification of SOC or total soil N; however, ZI decreased bulk density stratification. We concluded that ZT has the potential to improve both SOC sequestration and selected soil properties relative to NT and MP on fine-textured soils in cool, humid climates.