Geo-Morphologicalcharacterization and Land Constraint Assessment Using Geostatistical Approaches in Shirur Sub-Watershed in Kundagol Taluk
- P hd (Agri)
- Dharwad University of Agricultural Sciences, Dharwad 2024
- 338 32 Cms
A detailed study on geo-morphological characterization and land constraint assessment using geo-statistical approaches in Shirur sub-watershed in Kundagol taluk of Dharwad district was carried out during the year 2022-2024 in the Department of Soil Science and Agricultural Chemistry, UAS, Dharwad. The study was aimed to understand land geomorphology, soil characterization and classification, assess land constraints for evaluation of land capability, irrigabilityand crop suitabilityalong with assessing of spatial variabilityof soil properties within the sub-watershed. Nineteen representative pedons were studied fortheir morphological, physical and chemical properties, along with 601 surface soil samples were collected at 320 m × 320 m intervals using GPS. Based on these characteristics, soils were classified under three soil orders: Inceptisols (21.49%), Vertisols (69.02%) and Alfisols (4.35%), which were mapped into 67 distinct mapping units. The study identified three land capabilityclasses (II, III, IV) andthreesubclasses IIes, IIIs, IIIes and IVs withlimitationslike depth, erosion, gravelliness and texture. Identified land irrigability classes were moderately suitable (S2) and marginally suitable (S3). Crop suitability analysis indicated high suitability for crops such as sorghum (69.27%), maize (53.97%), redgram (69.07%), bengalgram (53.97%), groundnut (69.27%) and cotton (53.77%), while wheat, greengram, blackgram, soybean and horticultural crops were moderately suitable in the study area. Soil depth and texture constraints rendered study area less suitable for deep-rooted crops. Land geo- morphological characterization using morphometric analysis revealed a fifth-order drainage network with a total stream length of 137.38 km, moderate drainage density (2.13 km/km˛), while the areal parameters such as circularity ratio (0.56), elongation ratio (0.65) and form factor (0.32) indicated elongated basin shape. Relief parameters indicated slight to moderate erosion potential due to low elevation variation and longer water flow paths. Linear metrics like the bifurcation ratio reflected efficient stream branching, while ruggedness numbers emphasized areas susceptible to erosion. These parameters provided crucial insights into hydrological dynamics and erosion risks. Using ordinary kriging geo-statistical analysis tool, sub-watershed was mapped for soil properties and identified key constraints such as texture, gravelliness, depth, calcareousness and low levels of bio-available nutrients (N, P2O5, organic carbon and available Zn).Nugget to sill ratios indicated moderate spatial dependence for EC, organic carbon, available N, exchangeable Ca and Mg along with micronutrients. The soil pH, available P2O5, K2O and S showed weak spatial dependence, with deficiencies in 50.39 per cent of the study area for available zinc, along with low levels of available nitrogen (66.32%) and phosphorus (77.12%) in Shirur SW. The spatial distribution maps highlighted low organic carbon levels, with available potassium, exchangeable Ca and Mg, available S, Fe, Mn, Cu and B levels sufficient in most areas.