000			03571nam a2200205Ia 4500
003			OSt
005			20220103111204.0
008			130502s9999 xx 000 0 und d
040			_cCPGS
082			_a631.420954164
100			_aSaiborne, Ian Borney _9770
245			_aForms and availability of sulphur in the soils of Ri-Bhoi district of Meghalaya / _cby Ian Borney Saiborne
260			_aUmiam : _bCPGS, CAU, _cc2010
300			_a[28], 98p.: _bill., some col.;
440			_a[Soil Science and Agricultural Chemistry, School of Natural Resource Management] _9771
520			_aThe study was undertaken (i) to study the forms and availability of S in the soils of Ri-Bhoi district of Meghalaya (ii) to screen different extractants for identifying a promising extractant for estimation of Sand (iii) to study correlations between dry matter yield and uptake of sulphur by rape seed plant with soil properties. Forty two composite surface (0-15 cm) and sub-surface (15-30 cm) soil samples were analysed in the laboratory to measure the amount soil sulphur. The average total S of the soils range from 386.40 mg kg�� to 608.4 mg kg�� soil; Organic S was the dominant form of sulphur in all the land-uses contributing 90.46 to 96.83 per cent to the total S pool. A major portion of the total inorganic sulphate was found adsorbed in soil, and, soluble sulphate (0.15% CaCl?) comprised only 1.00 to 2.04 per cent of the total S in the soil. Eleven extractants were also screened out to assess their suitability as a soil test method for estimation of available S for the acidic soils of Meghalaya. Ca[H?P0?]? was found to be the most promising, showing good consistency in extracting soil sulphur and relationship with uptake of sulphur by rapeseed plant. The performances of different extractants in predicting available S in the soil and indicating their suitability as an extractant was in the following order Ca-phosphate > 0.25 M K-chloride > NH4-acetate + acetic acid> 0.5 M NaHC0? > 0.15 % Ca-chloride > Water-soluble S > Heat-soluble S > 0.25 M Hydrochloric acid. The other three agents viz., O.IM HCl, 0.25M HCl and Naacetate were unable to extract any sulphur in the acidic soil environment of Meghalaya. A pot experiment was also conducted in rabi season taking rapeseed plants as a test crop and ammonium sulphate as a source of S, to find out the response of the plant to S fertilization. Eight surface samples collected from two soil series in Ri-bhoi district were used for the experiment. Rape seed plant was found to respond to application of S in both the soil series used for the crop experiment. The application of S fertilizer at 20, 40, and 60 mg S kg��soil resulted in increased dry matter yield of the crop by 19.1 %, 30.9 %, and 50.34 % over control respectively. Similarly, the mean sulphur uptake was found to significantly increase with application of S fertilizer up to 40 mg S kg�� in two soil samples and up to 60 mg kg -I soil in five out of the eight soil samples. Application of S was also found to result in increase in uptake of other major nutrients viz., nitrogen, phosphorus and potassium. High correlations were found to exist between uptake of S and uptake of NPK by the plant (r = 0.823** - 0.976**; 0.693** - 986** and 0.639** - 0.973** respectively), indicating that S fertilization have synergistic effects on the uptake of other important nutrients by the plant.
650			_aSoils _xSulphur content _zRi Bhoi District _9772
700			_aLenka, N.K. _eMajor Advisor _9773
942			_2ddc _cTH
999			_c3991 _d3991