Erosional Losses and USLE Parameters in Relation to Land Cover Management

A field trial on runoff, soil loss and parameters of Universal Soil Loss Equation (USLE) in relation to land cover management was conducted (1993–98) at Central Soil and Water Conservation Research and Training Institute, Dehradun on 1.86 m 13.5 m erosion plots at 8 per cent slope. These plots were gauged utilizing multislot divisor and cisterns to measure runoff and soil loss. Methodology for estimation of USLE-parameters is described. The average rainfall erosion index for Dehradun is 1179 and the soil erodibility factor (K) is 84 kg ha⁻¹ per unit of rainfall factor (R). Chrysopogan fulvus grass effectively reduced runoff and soil loss by providing excellent land cover particularly at onset of monsoon and throughout the growing period. Maize (0.55 lakh plants ha⁻¹) with 4 t ha⁻¹ air-dry mulch also reduced runoff and soil loss effectively. The crop management factor ‘C’ for Chrysopogon fulvus was 0.04 and for maize having population of 0.55 lakh with 4 t ha⁻¹ mulch was 0.10. Maize with 1.1 and 1.6 lakh plants ha⁻¹ (50% of which was thinned and utilized as mulch after 30 days of sowing) reduced ‘C’ factor by 33 and 73 per cent as compared to conventional maize with 0.55 lakh plants ha⁻¹ population exhibiting 0.41 value of C factor. Ground cover through mulching proved more effective than above ground canopy cover. The total land cover comprising of crop canopy and ground cover of 4 t ha⁻¹ mulch provided adequate conservation of soil exhibiting 0.1 value of ‘C’ factor. The doses of air-dry mulch can be reduced up 2 t ha⁻¹ when the plant population is increased to about 1 lakh plants ha⁻¹.