Study on physical properties of rangeland at some slope levels in Nagari Aie Dingin, District of Lembah Gumanti, Solok Regency

Abstract

A field study was carried out in Nagari Aie Dingin, Lembah Gumanti District, Solok Regency. This research was aimed to examine the physical properties of Inceptisols at several slope levels in the research location. The soil samples were taken by purposive sampling based at slope levels (slightly steep [8-15%], moderately steep [15-25%], steep [25-45%], and very steep [>45%]), and in coffee field (25-45%) for two soil depths (0-30 cm and 30-60 cm). The results showed that the research area had silt loam, silty clay loam, and silt clay in texture. By increasing slope level (from 8-15% to >45%), soil organic matter content tended to decrease (from 5.74 to 2.58), bulk density increased (from 0.58 to 0.79 g/cm3), total soil porosity decreased (from 71.20 to 62.80), permeability rate decreased (from 9.47 to 4.01), for both soil depths (0-30 cm and 30-60 cm). Meanwhile, aggregate stability index was considered moderate. Compared to the land under coffee cultivation, the level of soil physical properties under the rangeland was still lower than that under coffee plantation. There was a negative correlation between SOM and soil BD (r (0-30 cm) = -0.85 and r (30-60 cm) = -0.69) and positive correlation between SOM and STP (r (0-30 cm) = 0.95, r (30-60 cm) = 0.80) and between SOM and soil permeability (r (0-30 cm) = 0.37, r (30-60 cm) = 0.85). Based on the fact, it is suggested to apply appropriate cultivation techniques and to provide suitable input in improving the soil physical properties.