An investigation of soil translocation and erosion by conservation hoeing tillage on steep lands using a magnetic tracer

The mechanism of tillage erosion has been increasingly recognized for nearly two decades, irrespective of mechanized or non-mechanized agriculture areas. Yet, control measures on tillage erosion were relatively less studied. A type of conservation tillage approach, referred to as “non-overturning hoeing tillage” was studied in comparison with conventional tillage in hilly areas of Chongqing, near the Yangtse Gorges reservoir areas, southwestern China. The magnetic tracer was used to label experimental plots of soil to measure soil translocation in the tillage direction. A comparison experiment between conventional and conservation tillage was conducted on a series of hillslopes with slope gradients ranging from 0.08 to 0.65 m m−1, with paired plots at neighboring sites on the same hillslope. Mean soil displacement in the downslope direction by conservation tillage, being 0.11 m was much shorter than that by conventional tillage with 0.33 m. Tillage transport coefficients were 17 and 35 kg m−1 tillage pass−1 when conservation tillage was conducted, and 37 and 118 kg m−1 tillage pass−1 under conventional tillage, respectively, for k3 and k4. Tillage erosion rates by conservation tillage, estimated at 28 Mg ha−1 year−1 significantly decreased with a reduction of 63%, when compared to those by conventional tillage estimated at 78 Mg ha−1 year−1. The magnetic tracer method is an efficient and effective one for measuring tillage translocation, and therefore, estimating tillage erosion rate. It is suggested that non-overturning hoeing tillage largely diminishes soil downslope translocation and results in a significant reduction in tillage erosion.