Executive Summary
Soil erosion in the upper Deli watershed results in nutrient loss, soil quality degradation, and negatively impacts agricultural production, thus threatening local food security. Steep topography and high rainfall rates accelerate erosion, exacerbated by agricultural practices that neglect soil conservation. Analysis indicates that soil erodibility (K) and slope length (LS) significantly increase erosion levels. Erosion leads to reduced crop yields and increased production costs. Immediate intervention through soil and water conservation techniques such as terracing, reforestation, and the use of modern monitoring technologies like GIS is necessary. Policy recommendations include soil conservation, critical land reforestation, and GIS technology for erosion monitoring. Implementing these policies is expected to reduce erosion rates, improve soil fertility, agricultural productivity, and community welfare.
Background
Soil erosion is a serious issue in the upper Deli watershed, causing nutrient loss, soil quality degradation, and negatively impacting agricultural production. This erosion strips away the fertile topsoil, reducing the soil’s capacity to support crops. The impacts of soil erosion economically harm farmers and potentially disrupt local food security.
The urgency to address this problem is high because soil erosion can drastically reduce agricultural yields, affecting the livelihoods and welfare of communities around the Deli watershed. Additionally, the nutrients lost from the soil will require significant time and cost to replenish, further adding to the economic burden on farmers.
The complexity of the issue is increased by the steep topography and high rainfall in the upper Deli watershed, which accelerate erosion rates. The steep slopes cause rainwater to flow rapidly over the soil surface, carrying away nutrient-rich soil particles. Additionally, agricultural practices that disregard soil conservation worsen the situation. In the long term, without effective mitigation efforts, soil erosion can lead to severe land degradation and reduce overall agricultural productivity in the region.
Therefore, immediate intervention is necessary to implement soil and water conservation techniques, such as terracing, reforestation, and the use of modern monitoring technologies, to reduce the negative impacts of soil erosion and ensure the sustainability of agriculture in the upper Deli watershed.
Analysis Results
The analysis of soil erosion issues in the upper Deli watershed shows that soil erodibility (K) and slope length (LS) significantly contribute to erosion levels in the area. Soil erodibility (K) measures the soil’s susceptibility to erosion, influenced by physical and chemical properties such as texture, structure, and organic content. An average K value of 0.160 in the upper Deli watershed indicates that the soil in this area is quite vulnerable to erosion.
Slope length (LS) also plays a critical role in accelerating erosion. The steeper and longer the slope, the greater the volume and speed of surface water flow, which causes the topsoil to be eroded. In the upper Deli watershed, the steep topography and high slope length exacerbate erosion conditions, especially during high rainfall events. Fast-flowing rainwater on the soil surface carries soil particles, including organic matter and essential nutrients, reducing soil fertility and agricultural productivity.
This study confirms that the combination of soil erodibility and significant slope length causes substantial losses in soil quality and agricultural productivity in the region. Eroded soils not only lose their fertile top layer but also require a long time to recover without proper intervention. These losses are directly felt by farmers through reduced crop yields and increased production costs due to the need for additional fertilizers to compensate for the lost nutrients.
