Effects of Tillage Methods on Soil Carbon and Wind Erosion

Abstract

Current interest in soil-conserving tillage in China has developed from the concern that Chinese agricultural land loses 73·8Mg C annually. Previous research has shown that changing from conventional tillage to conservation tillage field management increases soil C sequestration. The aim of this study is to determine if no tillage with stubble retention can reduce soil carbon loss and erosion compared with conventional tillage for a cornfield in northern China. We found that soil organic C storage (kgm-2) under conservation tillage in the form of no post-harvest tillage with stubble retention increased from 28% to 62% in the soil depths of 0-30cm (p<0·01) compared with the conventional tillage. Retaining post-harvest stubble with a height of 30cm and incorporating the stubble into the soil before seeding the next spring increased soil organic carbon the most. Carbon storage (kgha-1) in aboveground and belowground biomass of the corn plants in seedling and harvest stages was significantly greater (p<0·01) with stubble retention treatments than with conventional tillage. Carbon content in root biomass in all treatments with stubble retention was significantly greater than that with conventional tillage. Soil erosion estimates in the study area under conservation tillage with stubble retention was significantly lower than that under conventional tillage during the monitoring period. Given the complexities of agricultural systems, it is unlikely that one ideal farming practice is suitable to all soils or different climate conditions, but stubble retention during harvesting and incorporation of the stubble into soil in the next spring appears to be the best choice in the dry northern China where farmlands suffer serious wind erosion.