JOURNAL OF DEGRADED AND MINING LANDS MANAGEMENT ISSN: 2339-076X (p); 2502-2458 (e), Volume 8, Number 2 (January 2021): 2689-2702 DOI:10.15243/jdmlm.2021.082.2689 www.jdmlm.ub.ac.id 2689 Research Article Land-use changes and slope positions impact on the degradation of soil functions in nutrient stock within the Kalikungkuk micro watershed, East Java, Indonesia Anita Dwy Fitria 1 , Sudarto 2 , Syahrul Kurniawan 2* 1 Postgraduate Program of Soil and Water Management, Faculty of Agriculture, Brawijaya University, Jl. Veteran No. 1, Malang 65145, Indonesia 2 Department of Soil Science, Faculty of Agriculture, Brawijaya University, Jl. Veteran No. 1, Malang 65145, Indonesia * corresponding author: syahrul.fp@ub.ac.id Received 2 December 2020, Accepted 28 December 2020 Abstract: Degradation of soil functions in storing and cycling nutrients may be related to topography and land-use change. The research aimed to analyze the impact of land-use changes and slope positions on soil function in nutrient stock within Kalikungkuk micro watershed of East Java, Indonesia. Four different land- uses such as vegetable crops, agroforestry, shrub and forest were selected with three slope positions (e.g. ridge, slope, and valley), and three replications of each. Soil samples were collected at 0-10, 10-30, 30-50, and 50-100 cm depth of soil. Variables measured included soil properties (e.g. bulk density, soil texture, pH, CEC, soil nutrients). Slope positions impact on differences in soil physical (i.e. soil bulk density, soil texture) and chemical (i.e. total N, exchangeable K) properties. In addition, forest conversion to other land- uses (i.e. agroforestry, shrub, vegetable crops) decreased soil nutrient concentration (i.e. total C, total N, Ca, Mg, Na), and consequently resulted in degradation of soil nutrient stocks of especially C and N. The strong positive correlation between soil nutrient stock (e.g. C and N) and vegetation cover such as canopy cover, basal area, and litter (r = 0.63 – 0.78, r table 1% = 0.39) showed the benefit of biodiversity in maintaining soil function on the nutrient stock. Keywords: agroforestry, land-use change, slope positions, soil characteristics, soil nutrient stocks To cite this article: Fitria, A.D., Sudarto, and Kurniawan, S. 2021. Land-use changes and slope positions impact on the degradation of soil functions in nutrient stock within the Kalikungkuk micro watershed, East Java, Indonesia. J. Degrade. Min. Land Manage. 8(2): 2689-2702, DOI: 10.15243/jdmlm. 2021.082.2689. Introduction Soil plays an important role in sustaining biodiversity, storing and cycling nutrient, and regulating water and solute flow in the watershed. However, the functions of soil for the environment in the watershed area has decreased naturally (due to topography and climate effects) and/or mismanagement in the land (due to forest conversion to other land-uses) during the past fourth decades. Consequently, degradation of soil function will affect the sustainability of land productivity. Naturally, with the similar climate condition, degradation of soil function especially on nutrient stock and cycling under unmanaged land (i.e. forest, shrub) in the upstream watershed is mainly related to the variation of topography. Rodenburg et al. (2003) reported that topography (i.e. the level of slope and slope position) have an effect on the level of surface runoff and soil erosion. In addition, the previous research that was conducted in the upstream Brantas watershed showed the increases of runoff coefficient in the steep of topography with disturbed area by agricultural and human activities (Witjaksono et al., 2018). The runoff and soil erosion will carry water from the highest point to the lowest point along with different amounts of nutrients and parts of the topsoil. Consequently, the lower areas have an increase in soil nutrient