Assessment of Soil Fertility Status under Intense Tomato Growing Typic Kandiustalf Soils of Eastern Dry Zone of Karnataka

Abstract

The study was undertaken to assess the soil fertility status under intensively tomato growing fields in Typic Kandiustalf Soils of the Eastern Dry Zone of Karnataka. Composite surface (0-15 cm) and subsurface (15- 30 cm) soil samples from 100 locations representing different physiographic units were collected from the intensively growing tomato fields to estimate various physicochemical properties. Samples were analyzed for texture, bulk density (BD) and maximum water holding capacity (WHC) as physical properties and chemical properties such as (pH, EC, OC, N, P, K, Ca, Mg, S, Zn, Cu, Fe, Mn and B). Results revealed that soils were sandy loam in texture and mean BD and maximum WHC varied from 1.43 to 1.58 Mg m-3 and 37.1 and 30.7%, respectively for surface and sub-surface soils. The BD was found to increase with depth, whereas, MWHC was decreased with depth. The soils were slightly acidic and non-saline in nature. The organic carbon (OC) content was found to decrease with the increase in soil depth (0.51 to 0.34%) but cation exchange capacity (CEC) varied from 9.44 cmol(p+)kg-1 soil at surface to 10.04 cmol(p+)kg-1 at subsurface. Soils were low in available N (175.5 and 117.7 kg ha-1), medium in available (290.64 and 227.5 K2O kg ha-1) content and available P content (39.3 and 26.7 P2O5 kg ha-1) in surface and sub-surface soils, and adequate in secondary nutrients (Ca and Mg). The DTPA-extractable micronutrients viz. zinc (Zn), iron (Fe) and manganese (Mn) showed decreasing trend but DTPA-copper (Cu) and hot water-soluble-boron (B) showed increasing trend with increased depth and correlation of nutrients indicate its variation in availability. Low OC and nutrients in soils were attributed to low application of recommended dose of organic manures, high temperature and low rate of application of fertilizers, especially in the dry zones areas. Hence, availability of nutrients in soil influenced by the amount and type of fertilizers application, cropping system and management practices followed by the farmers.