CHANNABASAVE, R GOWDANAVEEN, D V2017-06-082017-06-082009-07-10TH-9391http://krishikosh.egranth.ac.in/handle/1/5810018698Sorption studies were conducted with pyrazosulfuron-ethyl using the batch equilibrium technique and HPLC analysis. Four different paddy growing soils of Kathalagere, Mandya, Mudigere and Mangalore soil. The sorption isotherm (n) values were 0.104, 0.101, 0.085 and 0.165 of Kathalagere, Mandya, Mudigere and Mangalore soils respectively. Freundlich constants ‘K’, ‘Koc’ and ‘Kc’ values were range from 5.45 to 9.52, 1099.46 to 1436.12 and 32.24 to 49.07 in different soils and described in the order of Kathalagere > Mandya > Mudigere > Mangalore, which is also in the order of decreasing organic matter content in the soils. The coefficient of determination showed an improvement 96 per cent using quadratic functions, the cumulative desorption of five days was ranged from ranged from 22.3 to 41.1 mg kg- 1 in Kathalagere soil, 25.6 to 49.4 mg kg-1 in Mandya soils, 37.1 to 51.9 mg kg-1 in Mudigere soil and 39.9 to 55.7 mg kg-1 in Mangalore soil. To study persistence and residues of pyrazosulfuron-ethyl in soil and ground water in transplanted rice ecosystem. Pyrazosulfuron-ethyl was applied at 25 g a.i. ha-1 and 50 g a.i. ha-1 with and without addition of FYM on flooded rice. The study revealed that the residue of pyrazosulfuron-ethyl in soils ranged from 0.0103 and 0.0199 mg kg-1 respectively (T2 & T4) on 2nd day of application. And with out FYM the residues were 0.0116 and 0.0229 mg kg-1 respectively (T1 & T3). The degradation of the initial residue with the time taken in both the treatments were up to 35 days. The half-life of pyrazosulfuron-ethyl ranged from 17.7, 16.6, 21.8 and 19.3 days for T1, T2, T3 and T4 respectively. After two weeks the residues were detected in ground water collected from both the piezometers which were applied with recommended and double the recommended dose of pyrazosulfuronethyl. A maximum of 0.0154 mg kg-1 on 21st day and minimum of 0.0023 mg kg-1 pyrazosulfuron-ethyl residues on 35th day were detected in underground water.ennullThesis