Agronomic, socio-economic, and environmental challenges and opportunities in Nepal's cereal-based farming systems

With economies heavily dependent on agriculture, South Asia is the world's most poverty-dense region. Nepal—a country of considerable geographic variability ranging from population-dense low-elevation Terai region to the sparsely inhabited, poorly accessible Himalayan hills and mountains—has enormous environmental and socio-economic challenges to agricultural development. Runoff from the hills and mountains feed networks of rivers that are crucial for supply of surface and groundwater for the Terai and northern India and Bangladesh, benefitting approximately one-fifth of the world's population. Nepal's farming systems are complex, with insufficient documentation of research evidence on the challenges and opportunities facing them. This review documents the key environmental, socio-economic and agronomic issues affecting cereal-based farming systems in Nepal. Evidences suggest farmers in the hills and mountains primarily practice integrated crop-livestock-tree based agroforestry systems with local varieties of crop and livestock species, and use farm-derived organic amendments and limited external inputs, resulting in low but stable yields. The Terai's cropping systems are predominantly rice-based, with wheat, maize and pulses grown in rotation with low to moderate use of inputs, although high yielding varieties are increasingly common. Major environmental challenges in the high and mid-hills include erosion and soil degradation, while in the Terai, reduced soil fertility and sub-optimal management of water resources are important constraints. Climate variability and extremes are cross-regional challenges. Socioeconomic issues include land use policy, labor out-migration and agricultural feminization. Large gaps between potential and farmers' yields are consistent concerns. While summarizing past and current agronomic research findings, this review suggests new research needs and agricultural development pathways that could address these environmental, socioeconomic and agronomic issues and challenges.