Conservation Tillage and Soil Physical Environment.

Conservation tillage system effects on soil C sequestration, soil fertility, and crop yields have been widely discussed, but its impacts on the soil physical environment have not been specifically discussed. Thus, an improved understanding of conservation tillage systems on soil physical quality, which influence agronomic productivity and environmental quality is needed. The objective of this review is to synthesize published data on conservation tillage systems as compared with conventional tillage systems on soil physical properties and highlight gaps in our current understanding. Conservation tillage, in general, increases bulk density and penetration resistance compared to conventional tillage. The few studies on strip till suggest that this system can reduce both bulk density and penetration resistance compared to no-till. One of the soil properties that is consistently improved by no-till is wet aggregate stability. On average, conservation tillage increases wet aggregate stability by about 70% compared to conventional tillage. Conservation tillage has mixed effects on water infiltration, water retention, and saturated hydraulic conductivity. However, soil water retention generally improves or remains unchanged in most studies with conservation tillage. Soil temperature generally decreases with conservation tillage in spring, summer, and fall. Few studies exist evaluating the effects of strip till on soil physical properties compared to no-till or conventional tillage practices. Overall, conservation tillage can improve soil structural stability and have inconsistent effects on soil hydraulic properties.