Vol. 6, Issue 5 (2018)
An assessment of mitigation measures for atrazine in calcareous sandy loam soil with maize
Author(s): C Bharathi and C Chinnusamy
Abstract: A pot culture experiment was conducted to assess the effect of organics and microbes in mitigating atrazine in soil. The experiment was carried out during 2017-18 at Tamil Nadu Agricultural University, Coimbatore with the test crop of maize. Soil samples were collected from the field which did not receive the atrazine previously and used for conducting the pot study. About 10 kg soil was filled up in each pot. The soil used for the study is calcareous sandy clay loam in texture having pH 8.28,EC 1.2 dS/m, OC 0.46%, available N,P,K of 145.6, 17.8 and 621 kg/ha. The treatments constituted application of FYM, green manure, crop residues, biochar, urea and microbes Viz., Tricoderma, Pseudomonas, phosphorbacteria and VAM along with control. The treatments were imposed 3 days before sowing of maize. Atrazine was applied to each pot equivalent to 0.5 kg/ha on 3rd day after sowing maize. Soil samples were collected from a depth of 0-15 cm on 0, 1, 3, 5, 10, 15, 30 and 45 DAA and analysed for atrazine residues. A valid homogenized representative soil sample from each replication of each treatment was taken and the atrazine was extracted using solvent mixture consisting methanol: water (7:3). The soil-suspension was centrifuged and the supernatant was filtered. The above step was repeated two times and the supernatant phase was combined and concentrated to dryness. The residues of atrazine were dissolved in HPLC grade acetonitrile and determined by HPLC equipped with Photo Diode Array Detector at a wave length of 221 nm. The initial deposition on day 0 (After 1hour) ranged from to 0.423 - 0.721 mg / kg across different treatments sources consisting of cultural and microbes application to enhance the degradation of atrazine from the soil. The degradation equation, correlation coefficient and half lives were worked out. The results revealed that the dissipation was faster under FYM, vermicompost and biochar applied treatments and the slowest degradation was noticed in control. The lowest half life of 8.8 days was observed in FYM treatment. The dissipation of atrazine in soil followed first order reaction kinetics irrespective of sources of mitigation measures and about 80 percent of the initial atrazine deposition degraded from the soil on 45th day after its application. Based on the present results it was found that the FYM @ 10 t /ha or vermicompost @ 5/ha or biochar @ 5 t/ha is efficient in reducing the residual concentration of atrazine in maize grown soil. This could be due to the enhanced adsorption of the compounds by these sources. The application of FYM degraded the atrazine very fast with the half live 8.8 days and slow degradation by microbes could be ascribed to the low quantity of application when compared to FYM.
Pages: 2841-2845 | 260 Views 38 Downloads
download (5967KB)
How to cite this article:
C Bharathi, C Chinnusamy. An assessment of mitigation measures for atrazine in calcareous sandy loam soil with maize. Int J Chem Stud 2018;6(5):2841-2845.
