NAIDU, M.V.S.SATISH, S2019-05-102019-05-102018http://krishikosh.egranth.ac.in/handle/1/5810102697D5738The present investigation involves “Detailed soil resource inventory of Brahmanakotkur watershed in Kurnool district of Andhra Pradesh using remote sensing and GIS”. For this purpose, twenty one typical pedons from Brahmanakotkur watershed were studied for their physical, physico-chemical and chemical properties. The area was characterized by semi-arid monsoonic climate with distinct summer, winter and rainy seasons. The pedons occurs in plains (P5, P6, P7, P15, P16, P17 and P18), very gently sloping (P1, P2, P3, P4, P8, P12, P13, P14, P19 and P20) and gently sloping (P9, P10, P11 and P21) topography. The P3, P5, P6, P7, P8, P11, P12, P13, P14, P15, P16, P17, P18 and P19 were developed from limestone whereas P1, P2, P4 and P10 were originated from dolomite. The P20 and P21 were developed from quartz while P9 was originated from shale. The morphological features indicated the presence of A-Bw-C (P4, P9 and P10), A-Bss-C (P1, P2, P3, P5, P6, P7, P8, P11, P12, P13, P14, P15, P16, P17, P18, P19 and P20) and A-C (P21) profiles. The soils were shallow to very deep in depth, very dark gray to strong brown in colour, gravelly sandy loam to clay in texture and exhibited sub-angular and angular blocky structures. xviii The clay content in P1, P4, P5, P10 and P21 exhibited an increasing trend with depth whereas no specific trend with depth was observed in remaining pedons. Physical constants like water holding capacity, loss on ignition and volume expansion followed the trend of clay content. COLE value in P3, P6, P17 and P20 exhibited an increasing trend with depth whereas P1, P4 and P5 showed a decreasing trend with depth. However, no specific trend with depth was observed in the remaining pedons. The soils of watershed were neutral to strongly alkaline (7.01 to 9.11) in reaction, non-saline (0.10 to 0.82 dSm-1) and low to medium (0.01 to 0.58 %) in organic carbon. The CaCO3 content in soils was ranging from 2.43 to 18.71 per cent and ESP was low to high (0.81 to 22.64 %). The CEC values were medium to high (18.60 to 61.72 cmol (p+) kg-1) and exchange complex was dominated by Ca2+ followed by Mg2+, Na+ and K+. The soils were low (37.63 to 188.16 kg ha-1) in available nitrogen, low to high (2.29 to 151.51 kg P2O5 ha-1) in available phosphorous and potassium (73.92 to 686.53 kg K2O ha-1) and deficient to sufficient (0.62 to 22.50 mg kg-1) in available sulphur. The soils were sufficient in DTPA extractable Cu and Mn and deficient to sufficient in DTPA extractable Zn and Fe. Based on CEC / clay ratio, physical, chemical and physico-chemical properties, the mineralogy class for P1, P2, P3, P4, P5, P6, P7, P8, P11, P12, P13, P14, P15, P16, P17, P18, P19 and P20 was smectitic while mineralogy class for P9, P10 and P21 was mixed. Based on the morphological, physical, physico-chemical, mineralogical and meteorological data, the soils were classified as Vertisols , Inceptisols and Entisols orders and these soils were classified at family level as: Pedons 1, 8, 11, 14 and 20 : Fine, smectitic, isohyperthermic, Typic Haplustert Pedon 2 : Fine-loamy, smectitic, isohyperthermic, Sodic Haplustert Pedons 3, 18 and 19 : Fine, smectitic, isohyperthermic, Typic Calciustert Pedon 4 : Fine-loamy, smectitic, isohyperthermic, Lithic Haplustept Pedon 5 : Fine, smectitic, isohyperthermic, Leptic Calciustert Pedons 6, 7, 12, 15, 16 and 17 : Fine, smectitic, isohyperthermic, Sodic Haplustert Pedon 9 : Fine-loamy, mixed, isohyperthermic, Typic Haplustept Pedon 10 : Loamy-skeletal, mixed, isohyperthermic, Typic Haplustept Pedon 13 : Fine, smectitic, isohyperthermic, Sodic Calciustert Pedon 21 : Loamy-skeletal, mixed, isohyperthermic, Lithic Ustorthent xix Twelve soil series were identified in the study area and were mapped into twelve different mapping units. The twelve mapping units were classified into five land capability sub-classes such as IIs (BRK2bB1g1D4, BRK5cB1g1D4, DGP4dA1g1D4 and PPLdA1g1D5), IIes (DGP2bC2g1D2), IIIs (BRK1dA1g1D5, BRK3dB1g1D5, BRK4cB1g1D1, BRK6cB1g1D5 and DGP1cA1g1D), IIIes (GGPaC2g2D2) and IVes (DGP3aC2g2D1). Similarly, the soils of watershed were grouped in to five land irrigability sub-classes namely, 2s (BRK2bB1g1D4, BRK5cB1g1D4, DGP4dA1g1D4 and PPLdA1g1D5), 2es (DGP2bC2g1D2), 3s (BRK1dA1g1D5, BRK3dB1g1D5, BRK6cB1g1D5 and DGP1cA1g1D3), 3es (BRK4cB1g1D1 and GGPaC2g2D2) and 4es (DGP3aC2g2D1). The soil-site suitability evaluation of the study area revealed that mapping units such as BRK1dA1g1D5, BRK3dB1g1D5, DGP1cA1g1D3, DGP2bC2g1D2, DGP3aC2g2D1 and GGPaC2g2D2 were not suitable (N) for growing rice crop whereas the mapping units like BRK2bB1g1D4, BRK4cB1g1D1, BRK5cB1g1D4, BRK6cB1g1D5, DGP4dA1g1D4 and PPLdA1g1D5 were marginally suitable (S3) for growing rice crop. All the mapping units were marginally suitable (S3) for growing maize and bengalgram crops except DGP3aC2g2D1 which was not suitable (N) for growing maize and bengalgram crops. The mapping units viz., BRK2bB1g1D4, BRK4cB1g1D1, BRK5cB1g1D4, BRK6cB1g1D5, DGP1cA1g1D3, DGP2bC2g1D2 and GGPaC2g2D2 were marginally suitable (S3) for growing sunflower crop whereas the mapping units such as BRK1dA1g1D5, BRK3dB1g1D5, DGP3aC2g2D1, DGP4dA1g1D4 and PPLdA1g1D5 were not suitable (N) for growing sunflower crop. Production potential revealed that, actual productivity of soil mapping units was poor, average and good whereas potential productivity of soil mapping units was good and excellent. The coefficient of improvement (Ci) varied from 1.59 to 3.42 indicating the implementation of judicious soil and water management practices to sustain crop productivity. Soil fertility maps were also prepared for watershed for various parameters such as pH, EC, organic carbon, available macronutrients (N, P2O5, K2O and S) and micronutrients (Zn, Fe, Cu and Mn) under GIS environment using ArcGIS 10.3 version. Comparison of satellite data collected during the year 2009 with that of satellite data collected during the year 2016, indicated that, the soil and water conservation structures in the watershed, increased the area under agriculture by decreasing the area under scrub land and canal dump which is further supported by an increase in the vegetation vigour and also NDVI values from negative to 1.en-USnullThesis