Long-term effect of integrated farming systems on soil erosion in hilly micro-watersheds (Indian Eastern Himalayas)

Abstract

Soil erosion from traditional hill agriculture is a major concern for agronomic development in the Eastern Himalayas (India). An integrated farming system (IFS: is the combination of multipurpose trees-MPT interspersed with seasonal agricultural crops) may reduce the severity of erosion while ensuring food and nutritional security. The aim of our study was to identify an IFS, resistant to soil erosion in the hill ecosystem of Eastern Himalaya. For this, eight micro-watershed (MW)-based IFSs namely livestock with fodder crops (MW1), forestry (MW2), agroforestry (MW3), agriculture (MW4), agrihorti- silvi-pastoral (MW5), horticulture (MW6), cultivated fallow (MW7), and abandoned shifting cultivation (MW8, as traditional land use) were established and soil erosion was measured for 24 years in the sloping land (32.0%–53.0%) of the Eastern Himalayas (Meghalaya, Northeast India). In the forests (MW2), annual average (IA: 1983–2006) runoff and soil losses were 405.5 (±113) mm and 11.0 (±2.4) Mg ha 1 yr 1, respectively. The conversion of forests to cultivation caused a decline in the parameters of hydro-physical quality and fertility, more severely in the traditional farming (MW7&8) than in the IFS mode of cultivation (MW3,5,&6). Soil water conservation measures (SWCMs: contour bunding, terracing, and grassed waterways) were more effective at reducing erosion when used together compared to individually. Adoption of these SWCMs in cultivated MWs in IFS mode (MW3,5,&6), reduced the runoff by 13.0%– 17.1% and soil loss by 12.6%–15.1% over forests (MW2). However, in traditional agriculture (MW7&8), runoff increased by 50.6%–87.6% while soil loss was 50.3%–59.8% higher over the forest. The study demonstrated that the adoption of agroforestry, agrisilvi- horti-pastoral or horticulture-based IFSs with appropriate SWCMs may be promoted to reduce soil erosion while sustaining soil quality attributes and food security in the hill ecosystem of the Indian Eastern Himalayas.