Soil erosion control in immature oil palm plantation

The objectives of developing oil palm plantations should feasible economically and without causing massive erosion. This research proposes soil and water conservation strategies that are ideal and optimal for oil palm cultivation depending on land capability class. The conservation test for plants was performed according to land capability classes on a plot measuring 22 m × 4 m. Runoff and erosion rates were measured using Multislot Divisor Method. Nutrient leaching was analysed based on the content of C-organic (Ctot) (Walkley–Black method), total nitrogen (Ntot) (Kjeldahl method), P-available (Bray-1 method) and K2O (extraction with 1N NH4OAc at pH 7.0). From the results, land capability class III, cover crops (soybean) + manure (P3) treatment effectively reduced runoff and soil erosion (22.63 m3∙ha–1∙y–1 and 13.04 Mg∙ha–1∙y–1), as well as nutrient leaching, compared to other treatments. Furthermore, sediment trap + cover crop + manure (P3) controlled runoff, erosion and nutrient leaching on land capability class IV, producing the lowest runoff (129.40 m3∙ha–1∙y–1), soil erosion (11.39 Mg∙ha–1∙y–1), C-organic (1.3%), and P (1.95 mg kg–1). Soil conservation treatment significantly reduced erosion and runoff (p < 0.05) on land capability class VI. The bench terrace + cover plants + manure treatment-controlled runoff, erosion, and soil nutrient leaching.