Land-use change from the forest to others will affect the soil’s physicochemical properties. The research was conducted to identify soil physicochemical properties affected by land-use change in Sungai Batang, the east-south part of Maninjau caldera. The research used a survey method from which soil was sampled at four different types of land use (forest, bushland, mixed garden, and paddy soil) at 0-30 cm depth with three replicates. The results show that the soil in Sungai Batang was still developing. It was indicated by coarse soil texture (clay loam to sandy clay loam). Land-use change from the forest to other uses has altered some soil physicochemical properties. It increased soil bulk density and decreased total soil porosity, permeability rate, SOM content, and  total-N. However, there was an increase in  soil characteristics, especially soil P-availability, CEC, Ca-  and Na-exchangeable . While the soil pH  (H2O), K-and Mg-exchangeable stayed the same. In general, land use changed from forest to other use, mostly farming land degraded physicochemical characteristics of the soil derived from volcanic materials in Sungai Batang. That was mainly due to the decrease in SOM content.

Maninjau Village, including the tourist destination of Buya Hamka in Sungai Batang, is susceptible to natural disasters, such as landslides. It happens due to the sloping and high rainfall (> 3000 mm per year) area. The soil is prone to landslides if the sloping land is intensively cultivated for crop growth. This community engagement activity socialised and practised alley cropping techniques to manage farming in the sloping area. This method for introducing the alley cropping technique was through presentation and discussion as well as practice in the field with a farming group “Sehati”, a member of KPGH (Hamka generation youth community), and community leaders of the Nagari Sungai Batang in November 2021. A farmer cultivating red onion adopted the alley cropping method for the farm having a 19o39’ (36%) slope level with an alley width was 5 m. Gliricidia sepium and Tithonia diversifolia, known as green manure crops, were placed perpendicular to the slope of the alley fence. Gliricidia was planted every 5 m, and Tithonia between the Gliricidia at a 0.2 m distance in the alley fence.