Spatial Variability of Soil Properties under Different Land Use in the Dang District of Nepal

A study was carried out in the eastern part of Dang district in Nepal to assess the variability of selected soil properties due to different land use and map their spatial distribution. Considering three land use types (agriculture, agroforestry, and grassland), a total of 120 samples were collected from surface soil (0 to 15 cm depth) in May 2015 and analyzed for soil fertility parameters: pH, organic matter (OM), nitrogen (N), phosphorus (P), potassium (K), boron (B), and zinc (Zn). Results revealed that the average value of soil pH significantly (P<0.05) varied from 7.05 in agroforestry to 7.53 in agriculture land use. Soil OM and N contents were medium in range in all land use with slight variation, the highest average OM and N found in grassland (2.87% and 0.14% respectively), followed by agriculture (2.64% and 0.13% respectively), and agroforestry (2.45% and 0.12% respectively). Further, the results showed significant variation for P among agroforestry (18.99 kg ha-1) and grassland (8.49 kg ha-1) while the K content was the highest for grassland (144 mg kg-1) and lowest for agriculture (120 mg kg-1). Micronutrients- B was low (0.28 to 0.35 mg kg-1) and Zn was very low (0.14 mg kg-1) in all land use. There is a need to add appropriate fertilizer N, P, B, and Zn to the soil in order to increase the fertility status under different land use. Spatial variability maps for soil chemical properties can be used by farmers and local planners to make effective soil management strategies.