Land Degradation

Abstract

Land degradation is one of the major issues facing by Nepalese agriculture and can mostly be attributed to the loss of soil coupled with heavy rainfall during the monsoon season. Furthermore, soil nutrient mining, soil organic carbon depletion, floods, and chemical degradation are other forms of soil degradation. Based on the literature and our own observations, we elucidate the land degradation status in Nepal, around 12% of which is affected by the degradation process. Forest land (38%), Pasture/rangeland (37%), and agricultural land (10%) are under the threat of serious degradation for which urgent land management for restoration is required. Soil erosion by water solely accounted for 45.5% of the area under degradation, followed by wind erosion (4% of total area), chemical degradation (0.3% of total area), and physical degradation (0.2% of total area). Rill-erosion, inter-rill erosion, and gully erosion are serious threats facing the Mountain regions. Sheet erosion and floods are serious threats facing the Tarai region. Physical degradation such as soil compaction, deterioration of the soil structure, and increase in bulk density are overlooked researchable issues in Nepal. Chemical degradation such as pesticide pollution in soils, nutrient imbalance and mining, and the leaching of storing herbicides are other issues that need addressing. The yearly loss of life and land due to floods and landslides are irrecoverable and directly affect the country’s economy. It is estimated that on average 6 t ha⁻¹ yr⁻¹ of soil is lost annually from Nepal, which strongly indicates the need for proper land management.