Dissipation of Sulfosulfuron in Soil and Wheat Plant under Predominant Cropping Conditions and in a Simulated Model Ecosystem

Abstract

Environmental fate and dissipation of the sulfonylurea herbicide sulfosulfuron was investigated in soil (inceptisol) and wheat plant under predominant cropping conditions. Studies were conducted in natural field conditions and in a simulated model ecosystem. Thirty days after the wheat seeds had been sown, sulfosulfuron [N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-2-(ethylsulfonyl)imidazo[1,2-a]pyridine-3-sulfonamide] 75% w/w WG formulation was applied once in the field. The dosages were 25 and 50 g of active ingredient (ai)/ha. Studies were conducted in significantly separated individual plots to avoid contamination. In a predetermined interval, soil samples were collected and analyzed for the residues of sulfosulfuron. At harvest, wheat grain, straw, and soil samples were analyzed for the residues. Similar experiments were conducted in a model ecosystem. Apart from this, after harvest, the succeeding crops coriander (Coriandrum sativum) and edible amaranth (Amaranthus mangostanus L.) were raised in the model ecosystem and studied for the residues. No residues were detected in wheat grain, straw, and soil samples collected at harvest from both experiments or in the succeeding crops coriander and edible amaranth in the model ecosystem when tested at the minimum detection level of 0.001 microg/g. The dissipation of sulfosulfuron was found to have first-order kinetics in soil and plant in both studies. The dissipation data of sulfosulfuron in the model ecosystem were compared with those from the natural field conditions.

Identification of Residues of Sulfosulfuron and its Metabolites in Subsoil-dissipation Kinetics and Factors Influencing the Stability and Degradation of Residues from Topsoil to Subsoil Under Predominant Cropping Conditions

“…The sample was filtered in to a round-bottomed flask; the volume was reduced to 50 ml. Further, purified the samples (Ramesh & Maheswari, 2003) from associated interferences and used for quantification. Un sprayed control soil sample collected close to the test site was also analyzed.…”

Application Timing and Degradation Rate of Sulfosulfuron in Soil Co-affect Control Efficacy of Egyptian broomrape (Phelipanche aegyptiaca) in Tomato

“…However, at this temperature, differences between sulfosulfuron degradation in H. Eden and Kalanit were not significant. First-order kinetics degradation is assumed for many pesticides (Beulke et al 2000; FOCUS 1997) and has been previously reported for sulfosulfuron degradation in the soil (Maheswari and Ramesh 2007; Ramesh and Maheswari 2003). The temperature dependence of pesticide degradation in the soil has also been reported, and its quantification has been used for simulation of persistence in field conditions (Beulke et al 2000; FOCUS 1997).…”

“…To test the correlation between P. aegyptiaca control efficacy and residual sulfosulfuron concentration at the critical period (200 GDD), predicted daily concentrations after preplant incorporation were calculated as follows: first, the sulfosulfuron degradation rate constant, at 15 and 25 C in each soil, was quantified from the constant temperature experiments. Based on previous reports on sulfosulfuron degradation in soil (Maheswari and Ramesh 2007; Ramesh and Maheswari 2003) first-order kinetics was assumed; hence, the integrated form of the first-order reaction equation was fit to the measured data and used to quantify the rate constant (Equation 3): where C ( t ) is sulfosulfuron relative concentration (%) at time t (d); C (0) is the initial concentration (%), and k ( T ) is the degradation rate constant (d −1 ) at temperature T (C).…”

Dissipation of the Insecticide Cyantraniliprole and Its Metabolite IN-J9Z38 in Proso Millet during Cultivation

“…The dissipation pattern in grain and straw was expressed by the function of exponential decay as follows: C t = C 0 × e −kt , where t is the number of days after pesticide treatment, C 0 is the highest concentration of total cyantraniliprole residue, and k is the dissipation rate constant. In accordance with the equation obtained from the field data, the biological half-life in days (DT 50 ) was calculated from the following equation: DT 50 = ln (0.5)/ k 23–26 .…”