Field Persistence of Repeated Use of Atrazine in Sandy Clay Loam Soil under Maize

Abstract

Field experiments were conducted with maize as a test crop during 2006-2009 to study the effect of atrazine on its persistence and residue in soil and crop produce as influenced by the quantity of application and seasons. The treatments imposed were control, 0.5 and 1.0 kg ai of atrazine ha-1 and were replicated thrice in randomized block design. For residue analysis, the soil samples were collected at periodical intervals from 0 day to harvest and the crop produce were also sampled at post harvest. The atrazine was determined using GC equipped with FID detector. Persistence of atrazine in soil showed a gradual degradation with advancement in crop growth. The application of atrazine at recommended dose left no residue in the soil whereas the application of atrazine at double the recommended dose recorded 0.056 ppm of atrazine residue in the post harvest soil. Pooled data showed that the dissipation of atrazine was biphasic in nature and the degradation was faster at higher dose of application than at the lower dose. Degradation of atrazine in soil followed first order kinetics and the mean half life of atrazine was 21.54 days. Persistence of atrazine was also influenced by the season and years of application.