Effect of land criticality on nutrient availability (case study of Dinoyo sub watershed, Jember regency, Indonesia)

Dinoyo sub-watershed is one of the watersheds that drain water from Argopuro Mountain through the Panti and Rambipuji Districts. Land-use changes in the upstream area have reduced the function of water absorption and increased soil erosion. It causes drought during the dry season and flooding during the rainy season which is a characteristic of critical land. This study aims to map the level of criticality of the Dinoyo sub-watershed area and its relationship to nutrient availability. This study used the scoring and weighting method of four main factors that affect the critical value of land (land cover, slope, management, and erosion level). The layers then executed using the Gis program. The result of this analysis produces a land criticality map. Based on the analysis, the up-stream section has high nutrient availability compared to the middle and downstream regions. There are two classes of land criticality, which are rather critical and substantial criticism. The area included in the rather critical was 1,723.34 ha dominated by forest land use. A coffee plantation dominates a sizeable critical area of 2,333.88 ha. From regression analysis showed that organic matter had the most influence on the criticality of land.