Effect of Long-Term Tillage Practices on Runoff and Soil Erosion in Sloping Croplands of Himalaya, India

Slopy agricultural lands are more susceptible to soil erosion and hence are priority sites for the application of protective soil management practices. A conservation agriculture field experiment was established at a 6% field slope in 2011 at the ICAR-IISWC Research Farm, Dehradun, Uttarakhand, which is situated in the Northwestern Himalayan Region, India. The objective of this study was to experimentally determine the long-term effects of tillage practices on runoff and soil erosion. The tillage practices opted for were conventional tillage (CT), minimum tillage (MT), and zero tillage (ZT). Event-based runoff and soil loss were monitored during three monsoon seasons (June to September) from 2018 to 2020. Results showed lower runoff and soil loss in the ZT plot than in CT and MT plots. CT produced 1.51 and 2.53 times higher runoff than MT and ZT, respectively. Moreover, this increased runoff generated 1.84 and 5.10 times higher soil erosion in CT than in MT and ZT, respectively. The extreme rainfall events being less than 10% generated 54.93%, 57.35%, and 63.43% of the total runoff volume which resulted in 82.08%, 85.49%, and 91.00% of the total soil loss in CT, MT, and ZT plots, respectively. For the same amount of rainfall, the reduction in soil loss was 39% and 68% in the CT and ZT plots, respectively, at the highest growth stage in comparison to the initial crop growth stage. The values of runoff reduction benefit (RRB) and sediment reduction benefit (SRB) showed a reduction in runoff (63.53%) and soil loss (80.39%) in the CT. Results concluded that conservation tillage reduced runoff and soil loss significantly even in extreme rainfall events.