Changes in soil exchangeable nutrients across different land uses in steep slopes of Mizoram, North-east India

Abstract

Land use change resulting from anthropogenic pressure on land has led to degraded soil quality, especially in the hilly tropical regions where ecosystems are generally fragile and susceptible to soil degradation from cultivation. Hence, sustainable land uses and management practices are crucial for agricultural production and ecological balance, particularly in these regions. The present study investigates the impact of various hill land uses (Natural forest-NAF, Jhum fallow-JF, Home garden-HG, Acacia pennata plantation-AP and Current Jhum-CJ) on soil exchangeable nutrients in steeply sloping agro-ecosystems of Mizoram, North-east India. Soil samples were collected from three different depths (0-10, 10-20 & 20-30 cm) and analyzed for pH, Pavail, Na, K, Mg, Mn and Ca. Our results indicated that land use and soil depths had a significant impact on soil pH, Pavail and soil exchangeable cations (p<0.05). Conversion of native forests for cultivation negatively affected soil properties as indicated by the reduced soil exchangeable cations in cultivated lands (AP & CJ) in relation to the natural forest (NAF) and Jhum fallow (JF). Soils under longer periods of fallow (>12 years) led to increases in soil available nutrients indicating the role of vegetation cover in conserving and enhancing soil available nutrients and vice-versa. In addition, Home garden (HG) showed moderately higher available soil nutrients signifying the role of sustainable management practices such as the addition of organic amendments and mixed cropping, leading to increased soil available nutrient content.