National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Conservation agriculture (CA), an input saving concept has gaining momentum in India to address the labor shortage, soil health and sustaining crop productivity. However the adoption of CA practices has issues of poor weed control, increased herbicides application etc. due to loss of efficacy. This may also alter the persistence and dissipation behavior of herbicides in soil. Hence field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore during 2014-16 to study the influence of different combinations of CA practices and weed management methods on the persistence of atrazine and pendimethalin applied to maize-sunflower cropping system. The experiments were laid out in strip plot design with three replications. Main plot consisted of 1 conventional practice, 3 combinations of conventional and zero tillage practices with and without crop residue incorporation and one complete zero tillage with residues across maize and sunflower growing seasons. Sub plots consisted of three weed management methods viz., PE herbicides (Atrazine 0.5 kg/ha for maize and pendimethalin 1.0 kg/ha for sunflower), PE herbicides (Atrazine 0.5 kg/ha for maize and pendimethalin 1.0 kg/ha for sunflower) plus hand weeding on 45 days after sowing and control. Results showed that the initial residue of pendimethalin in sunflower field soil was 0.423 to 0.482 mg/kg and atrazine in maize field soil was 0.239 to 0.316 mg/kg respectively. Dissipation of both the herbicides followed first order reaction kinetics with the half life of 14.9-19.6 and 14.7–19.7 days, respectively for pendimethalin and atrazine. Dissipation of pendimethalin was slow under CA practices and vice versa for atrazine. Herbicides nature, crop residues type and crops grown have effect on the herbicides degradation through herbicide interceptions. Weather variables like rainfall, temperature and sunshine hrs also has interactive influence on herbicides dissipation along with CA practices. Results suggest that the influence of CA practices should be studied under long run to understand the changes in the efficacy and behaviour of herbicides in soil.
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