Soil and Nutrient Losses from Upland Agriculture Under Traditional and Restorative Management in the Central Nepal Middle Hills

  • K R. Tiwari Institute of Forestry, Tribhuvan University, Pokhara, Kaski, Nepal
  • R. M. Bajracharya Departrnent of Biological and Environmental Sciences, Kathmandu University, Dhulikhel, Kavre
  • J. Pathak Departrnent of Biological and Environmental Sciences, Kathmandu University, Dhulikhel, Kavre
  • B. K. Sitaula Department of International Environment and Development Studies, Norwegian University of Life Sciences, As, Norway
  • M. K. Balla Institute of Forestry, Tribhuvan University, Pokhara, Kaski,

Abstract

A preliminary study was conducted in a mid-hll watershed in Dhading district, Nepal, to evaluate the efficacy of reduced-till (RT)  and Banmara mulchmg (BM) application for soil restorative management as compared to the traditional farmer practice (FP). Twelve runoff plots were established along a single broad, gently sloping terrace (12.5 to 17%) and four replications of each treatment applied. Runoff and soil loss were hghest for the RT treatment, being nearly twice that of FP for runoff and three-times that of both FP and BM for soil loss. About 30 to 60% of total runoff and 50 to 60% of total soil loss occurred in the first major storm event during the pre-monsoon period. Nutrients lost in runoff were also highest for RT, with relative amounts of nitrate, phosphate and potassium following a similar trend for all three treatments. The mulching treatment offered the best maize biomass yields while providmg equally good runoff and soil loss control as FP. The reduced tillage option, however, performed poorly in the short-run, although its effectiveness as a soil restorative measure without sacrificing yields could improve in the long- tern Further, longer duration research is required to confirm its suitability in the mid-hills of Nepal.