Arrangement of Agricultural Reservoir Along Rill Erosion: Case Study in the Sumbing Volcanic Landscape, Java, Indonesia

Background and research aims: Most of volcanic landscapes on Java, Indonesia, are increasingly being used for agriculture. As a consequence, high rate of soil erosion due to agricultural cultivation cannot be avoided. Agricultural reservoir is one of methods to maintain soil loss due to erosion. Most research to date, however, have been based on the function of the reservoirs rather than on the arrangement of the reservoirs which are usually locally specific. Thus, an evaluation of the arrangement for agricultural reservoir becomes a crucial innovation. This study was aimed at examining the effectiveness of agricultural reservoir arrangement along rill erosion in reducing runoff volume as well as erosion rate, and increasing sediment trapped. Methods: The research was conducted using the field survey method at a key sampling area by considering the dominant relief and land cover on the volcanic landscape of the Sumbing Volcano. Data collected includes soil properties (texture, organic matter, porosity, soil pore distribution, permeability, and soil infiltration rate), runoff discharge, runoff volume, and sediment delivery. Research started by determining the points for placing the agricultural reservoirs along the rill erosion and continued with field and laboratory measurements. Results: Our results showed that placing agricultural reservoirs along the rill erosion effectively reduced erosion by 99.97. Consequently, the erosion rate was only 5.5 × 10−4 ton ha−1. The effectiveness of agricultural reservoirs in reducing runoff volume and sediment delivery was 99.72 and 94.15, respectively. Conclusion: Agricultural reservoirs that are placed along the rill erosion effectively trap sediment and reduce runoff so that erosion rates decrease. Implications for conservation: Placing agricultural reservoirs along rill erosion can improve the effectiveness of reservoirs in decreasing the erosion rate. This strategy helps reduce runoff and sediment to maintain the productivity of agricultural land. Finding a suitable strategy for the evaluation of erosion and sedimentation processes has important implications for soil and water conservation.