Effect of the soil-implement contact area on soil translocation under hoeing tillage

Hoeing tillage is widely performed in mountainous areas of Southwest China, as a result of patchy and steep cropland. The effect of the soil-implement contact area on soil translocation by manual hoeing needs to be addressed to better understand the relationship between tillage implement and tillage erosion. This study aimed to explore the mechanism on the effect of soil-implement contact area on soil translocation under hoeing tillage. A series of tillage experiments were conducted with four fixed tillage depths (0.05, 0.10, 0.15 and 0.20 m) on 9 slopes ranging from 0.09 to 0.58 m m−1, respectively, and the subsequent data were compared with those acquired previously by different hoe blade widths. Tillage depth is a significant factor reflecting the soil-implement contact area especially for a constant width of hoe blade. Mean soil displacement distance increased with increasing tillage depth, and this effect is more pronounced for greater slope gradients. Tillage translocation rates were linearly related to slope gradient, but quadratically to tillage depth. As another factor reflecting the soil-implement contact area, the hoe blade width is also a significant factor influencing tillage erosion. Tillage transport coefficients (k4) can be predicted by the soil-implement contact area. It is suggested that minimizing the soil-implement contact area by either decreasing tillage depth or reducing the width of hoe blades are effective measures for combating tillage erosion.