Effect of herbicides fenoxaprop-p-ethyl and 2, 4-d ethyl-ester on soil mycoflora including vam fungi in wheat crop
2011
Gupta, Anil | Aggarwal, Ashok | Chhavi, Mangla | Kumar, Aditya | Tanwar, Anju
Wheat (Triticum aestivum L.) is the major staple food of India and its increased production is essential for food security. Weeds constitute one of the biggest problems in agriculture that not only reduce the yield and quality of wheat crop but also utilize essential nutrients. Hence, weed control is essential for increasing wheat production. Despite of its control on weeds, herbicides also affect beneficial non-targeted soil microbes including VAM fungi. Fenoxaprop-P-ethyl and 2, 4-D ethyl-ester are two most widely used herbicides in northern India to control monocot and dicot weeds, respectively. However, their effects on mycorrhizal fungi are seldom highlighted. Therefore, the present investigation was focused on the effect of these herbicides on soil fungi of wheat crop alongwith special emphasis on mycorrhizal fungi. Three doses of each herbicide i. e. fenoxaprop and 2, 4-D (recommended dose 0.1 kg/ha; 0.5 kg/ha, half of the recommended dose 0.05 kg/ha; 0.25 kg/ha and double of the recommended dose 0.2 kg/ha; 1.0 kg/ha), respectively, were applied and their effect on soil fungi was studied at 30th, 60th, 90th and 120th day of treatment. Warcup's soil plate method, wet sieving and decanting technique and rapid clearing and staining techniques were used for qualitative study, isolation of mycorrhizal spores and root colonization, respectively. Our results indicate that both herbicides had significant deleterious effects on soil fungi, mycorrhizal spore numbers and percentage root colonization and this effect increased with herbicide concentration. In our chemical warfare against weeds, it is necessary to avoid serious injuries to the beneficial soil microbes. Therefore, use of herbicides in high doses should be resorted to carefully and judiciously.
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