A land use planning recommendation for the Sumani watershed, West Sumatera, Indonesia

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In the present study, we provide a land use planning recommendation for land conservation and agro-economical production for the Sumani watershed in West Sumatra, Indonesia, where intensive agriculture has long been practiced. We based our land conservation management recommendations on soil erosion rates using the Universal Soil Loss Equation (USLE) determined in our previous paper (Aflizar et al. 2010). Our land use planning vision is to maintain current land use practices as much as possible. In sites where the soil erosion rate remains less than the tolerable erosion rate (TER) (14 Mg ha-1 y-1; a rate set by the Indonesian government) land use was not altered. When soil erosion rates exceeded the TER, we selected a new land use with a smaller CP-factor than the former land practice to reduce soil erosion rates. The recommended land use planning resulted in a 16.1% change distributed as follows: vegetable gardens with terracing (10%), vegetable gardens with contour cropping (1.8%) and sawah (4.3%). The changes made in the recommended land use plans could reduce soil erosion rates by 88%, a reduction from 58.9 to 7.1 Mg ha-1 y-1, with a total profit loss in agricultural production of only 3.9% in the Sumani watershed.