Assessment of Soil Erosion and Its Impact on Agricultural Productivity by Using the RMMF Model and Local Perception: A Case Study of Rangun Watershed of Mid-Hills, Nepal

Abstract

Soil erosion is a major concern for the environment and natural resources leading to a serious threat to agricultural productivity and one of the major causes of land degradation in the mid-hills region of Nepal. An accurate assessment of soil erosion is needed to reduce the problem of soil loss in highly fragile mountainous areas. The present study aimed to assess spatial soil loss rate and identified risk areas and their perceived impact on agricultural productivity by using the Revised Morgan–Morgan–Finney (RMMF) model and social survey in the Rangun watershed of Dadeldhura district, Nepal. Soil erosion was assessed by using data on soil, digital elevation model, rainfall, land use, and land cover visually interpreted from multitemporal satellite images, and ILWIS 3.3 academic software was used to perform the model. A household questionnaire survey (n = 120) and focus group discussion (n = 2) in identified risk areas were carried out to understand the people’s perception towards soil erosion and its impact on agricultural productivity. The predicted average soil erosions from the forest, agriculture, and barren land were 2.7 t ha−1 yr−1, 53.73 t ha−1 yr−1, and 462.59 t ha−1 yr−1, respectively. The erosion risk area under very low to low, moderate to moderately high, and high to very high covers 92.32%, 4.96%, and 2.73%, respectively. It indicates that the rate of soil erosion was lower in forest areas, whereas it was higher in the barren land. The cropped area of the watershed has been reduced by 2.96 ha−1 yr−1, and productivity has been decreased by 0.238 t ha−1 yr−1. The impacts such as removal of topsoil (weighted mean = 4.19) and gully formation (weighted mean = 3.56) were the highest perceived factors causing productivity decline due to erosion. People perceived the impact of erosion in agricultural productivity differently ( ∗ significant at P ≤ 0.05 ). The study concluded that, comparatively, barren and agricultural lands seem more susceptible to erosion, so the long-term conservation and management investment in susceptible areas for restoration, protection, and socioeconomic support contribute significantly to land rehabilitation in the Rangun watershed.

Land-use/land-cover changes and implications in Southern Ethiopia: evidence from remote sensing and informants

“…The decline in crop yield reputed by the informants agrees with other studies. For example, the erosion-induced reduction in crop yields is attributed to loss of fertile top soil, degradation of soil structure, reduction in organic matter, decrease in plant-available water reserves and nutrient imbalance (Bhandari et al, 2021;Lal and Moldenhauer 2008). The highlands of Ethiopia addressing as home to about 80% of the population making a strong base of rural community, and as a result the areas are threatened with erosion and loss of agricultural productivity (Worku and Tripathi 2015).…”

Application of Hyperspectral Technology Combined With Bat Algorithm-AdaBoost Model in Field Soil Nutrient Prediction

“…Although this study confirms that Ba AdaBoost model has a good estimation ability for OM, P and K, it does not explain the relationship among OM, P and K. This unexplained difference may be related to some factors ignored in this study. For example, farming is a common practice in this area, and its impact on soil erosion is serious [53]. In addition, fertilization has a significant impact on the distribution of OM, P and K in the surface soil of the study area [54].…”

Estimation of soil erosion using the Revised Universal Soil Loss Equation (RUSLE) in Relation to Landslides in Western Mid-hills of Nepal

“…In the Rangun Khola watershed of western Nepal, environmental hazards like landslides contribute to a higher rate of erosion and vice versa in the monsoon seasons (Bhandari et al 2021). There have been a number of landslide events recorded over the last decades, leading to erosion (Pathak and Devkota 2022a).…”