Effects of common herbicides on soil fungi in a maize (Zea mays) farm

Abstract

The increasing use of pesticides in Agriculture have raised concerns over the unintended consequences, especially multiple applications of various forms of pesticides on the same farm land during a particular production period. This field trial was conducted to evaluate the effect of common farmland application of herbicides i.e. atrazine, xtravest , 2,4-D, on the species and population of soil fungi. Soil samples were collected thrice at a three month interval (July, September and December 2010) from a herbicide trial site located in Iddo town, Iddo Local Government area of Oyo State, Nigeria.The herbicides were applied at recommended rates either singly or in combination over the 2009 / 2010 growing seasons on a maize field. Their effects were tested on the fungal species present and their abundance using the soil dilution method. Data collected were subjected to descriptive and inferential statistics.The results showed the presence of different fungal genera on all the treated plots including the control. The fungi populations observed include Aspergillus niger, Lasidiodiplodia theobromae, Nattrassia mangiferae, Trichoderma spp, Fusarium verticillum, Fusarium oxysporum, Rhizopus stolonifer, Macrophomina phaseolina and Colletotrichum gleosporioides. Lasidiodiplodia theobromae occured the most (15/16) times among the treatments, across the sampling periods while Rhizopus stolonifer occured the least (1/16) number of times among the treatments through the sampling periods.Although, there were reductions in the number of isolated fungi across all treatment periods, however, the reductions were not consistent. In conclusion, the application of herbicide(s) may not exclude the use of other forms of pesticides in the management of soil microorganisms on the farm.