Soil quality significance of goat pens positioned on the hilltop of sloping cocoa farms in Polman-Sulawesi

Abstract

Many smallholder cocoa farmers in Polman, West Sulawesi-Indonesia breed goats traditionally on hilltop of the sloped cocoa farms. The goat's manure is deposited under the pens, not distributed on the farm. We investigated the significance of this traditional goat breeding on the hilltop of sloping cocoa farms on soil quality based on the distance from the pens along the slope direction. We selected three sloped-cocoa farms where this traditional model had been practiced for years. The farms studied had 30 to 70% slopes, clay loam to clay soil textures. Along a transect lane, 0-5, 5-10, and 10-15 meters from the pen on each farm, we measured soil bulk density, hydraulic conductivity (HC), soil organic carbon (SOC), pH, soil nitrogen, phosphorus, potassium, cation exchangeable capacity (CEC) and earthworm population. This traditional practice improved soil quality compared to the adjacent farms which were not affected by the practice (control). Soil HC, SOC, N, P, K and CEC, and earthworm population were markedly higher under this system compared to the control, especially at 0 to 5 m distance from the manure deposit. The beneficial effects of this system were limited only within 10 m from the pens, beyond which soil quality was practically similar to the control site. This traditional system may be considered as an appropriate practice for soil quality maintenance in sloping cocoa farm, but an improvement is needed for greater benefits and reduced risks through terrace construction and manure deposition every 5-10 m range along the slope.