Nutrient losses from rain-fed bench terraced cultivation systems in high rainfall areas of the mid-hills of Nepal

Between the elevations of 1000 and 2000 m in the mid-hills of Nepal, over 12 million people subsist on land-holdings of less than 0.5 ha. These farmers have limited access to commercial inputs such as fertilisers and are reliant on organic manures for soil fertility maintenance. Participatory research was conducted with farmers on bari land (upper slope rain-fed crop terraces) in the hill community of Landruk (bench terraces 0-5 degrees slope, 3000-3500 mm annual rainfall, which aimed to develop soil and water management interventions that controlled erosion without resulting in high leaching, and so were effective in minimising total nutrient losses. Interventions tested were the control of water movement through diversion of run-on and planting fodder grasses on terrace risers on bench terraces. The interventions were effective in reducing soil loss from the bari land in comparison with existing farmer practices, but no effect was observed on nutrient losses in solution form through runoff and leaching. Losses of NO3-N in leachate ranged from 17.3 to 99.7 kg ha(-1) yr(-1), but only 0.7 to 5.6 kg ha(-1) yr(-1) in runoff. The overall nutrient balance suggests that the system is not sustainable. Fertility is heavily dependent on livestock inputs and if the current trends of declining livestock numbers due to labour constraints continue, further losses in productivity can be expected. However, farmers are interested in interventions that tie ecosystem services with productivity enhancement and farmers' priorities should be used as entry points for promoting interventions that are system compatible and harness niche opportunities. Copyright (C) 2007 John Wiley & Sons, Ltd.