Impact of farm yard manure on cropping cycle in a rainfed agroecosystem of Central Himalaya

Crops, livestock and forests are interlinked components of Central Himalayan agro-ecosystems. Traditionally, farm yard manure is produced from forest leaf litter and excreta of livestock obtaining > 50% feed from forests. Chemical fertilizers are not used in rainfed farms on slopes. Experiments were conducted to test whether increase in FYM input rates results improvement in economic and environmental functions of agro-ecosystems. Increase in FYM input rate from 30 t/ha/crop-season currently practiced by farmers to 60 t/ha/crop-season showed substantial increase in crop yield and soil quality. Rice and wheat were more responsive to FYM input than the legume black gram. Harvest index is maximum for 60 t/ha/crop-season FYM treatment for rice and wheat. In blackgram maximum harvest index was obtained when no FYM was provided. During the 3 years of study, soil pH decreased (becoming more acidic) as compared to that recorded at the start of the study. Soil organic carbon generally declined upto second kharif season and then improved during second rabi (fallow) under no input treatment, and 16t/ha/crop-season FYM treatment and levels of N, P and Mg too showed patterns similar to soil organic carbon, but the trends varied for Ca, Na and K. Soils of fields put to 0 and 16 t/ha/crop-season FYM treatments showed a net decrease in concentration of these elements and those put to 30 and 60 t/ha/crop-season FYM treatments showed increase in their level.