Effect of Three Conservation Tillage Practices on Soil Temperature and Thermal Properties

Abstract

Three conservation tillage systems, chisel (CH), till-plant (TP), and no-till (NT), were compared to conventional (moldboard) tillage (CN) for differences in depth zone (5 cm) and upper profile (5-15 cm) soil temperatures and related soil thermal properties. In-row spring soil temperatures were highest in CN, slightly lower in TP and CH, and lowest in NT. The maximum difference in daily average temperature observed between tillage treatments occurred on 2 May 1982 when the NT, CH, and TP treatments were 5.9, 2.3, and 1.8{degrees}C cooler than CN, respectively. Soil thermal diffusivity (K') in the 5- to 15-cm zone was 20 to 25% higher in the NT treatment than in the CN and CH treatments, which were not significantly different. In 1 of 2 yr, K' was significantly higher in the TP treatment than in the CN and CH treatments. The reduction in soil temperatures observed with conservation tillage was attributed to differences in thermal admittance ({micro}), heat flux to deeper depth, and total heat inputs to the soil profile. The higher thermal admittance and heat flux in the NT treatment produced lower upper profile soil temperature.