摘要：Propaquizafop is a new graminicide herbicide recommended for control of grassy weeds in all drylandand ID crops. A field experiment was conducted during Kharif 2012 at the College Farm, ANGRAU,Hyderabad, on a Alfisol, to study the dissipation and persistence of varying doses of propaquizafop(25, 50, 62.5, 100 and 125g a.i/ha) in soil and turmeric. The influence of the herbicide on soil physical,physico-chemical and fertility properties was also assessed. Residues of the propaquizafop in soiland soybean were estimated on GC-ECD. Recovery of the herbicide in soil was 91.8-92.6%. In therhizome and plant, the recovery was 88.6-92.1% and 93.6-93.8%, respectively. Limit of quantificationwas 0.01 mg/kg. No significant changes in physical (texture, bulk density, particle density, pore space,maximum water holding capacity), physico-chemical (pH, EC, CEC, organic carbon) and availablenutrient status of the soil (available N, P 2 O 5 and K 2 O) were noticed in any of the applied doses of theherbicide. Application of propaquizafop @62.5 g/ha resulted in highest bio-efficiency. Propaquizafopdissipation in soil followed a first-order decay process. Half-life of the herbicide in soil increased withincreasing dose. At sub-optimal doses, 50.0 g/ha, residues of propaquizafop persisted in the soil upto15 DAA, (days after application) with a half life (DT 50 ) of 15.12 days. At the recommended dose (62.5g/ha) half-life of propaquizafop was 17.67 days and residues reached below detectable limit (BDL)beyond 30 DAA. At doses above recommended level (100.0 and 125 g/ha), herbicide residues in thesoil persisted for a longer period (45 and 60 DAA respectively) with DT 50 of 21.29 and 29.36 DAA,respectively. No detectable residues of propaquizafop were detected in the turmeric rhizomes or plantat the time of harvest.
