Degradation Pattern and Residues of Atrazine in Maize under Long Term Conservation Agriculture

Field experiment was conducted at Eastern block farm, Tamil Nadu Agricultural University 11°29”N latitude and 77° 08”E longitude with an altitude of 426.7M above MSL with maize to study the degradation, persistence and residues of atrazine under long term conservation agriculture system. The treatments constituted atrazine 1.0 kg ha-1 on 3 DAS and atrazine 1.0 kg ha-1 on 3DAS +Hand weeding on 45th day under different conservation tillage practices. Degradation, persistence and residue analysis were carried out for atrazine using HPLC. Residues of atrazine was analyzed at different periods viz., 0,15,30,45,60,75 and 90 days after herbicide application and at harvest and the results revealed that degradation of atrazine was found to follow first order reaction kinetics (R2> 0.94) with the half life of 13.7–16.2 days irrespective of tillage practices and weed management methods. The recommended rate of atrazine @1.0 kgha-1 recorded terminal residues below detectable limit of <0.01 mg kg-1 in soil and plant parts of maize.