Effect of glyphosate on fungal population, respiration and the decay of some organic matters in Egyptian soil

Glyphosate (Roundup), when applied to the soil usually did not exert any significant effect on the total count of soil fungi after all periods of the experiment except after 6 and 10 weeks where the count was inhibited by the two doses used (1.84, 9.2 mg active ingredient/kg dry soil). When the herbicide wa incorporated into the agar medium the count of total fungi, Acremonium strictum and Aspergillus fumigatus was significantly increased by the two doses used and of Penicillium glabrum by the high dose only. However, P. funiculosum was completely eliminated by the high dose. Oxygen consumption in soil treated with glyphosate was significantly inhibited by the high dose after 2 weeks and by the two doses after 6, 8 and 10 weeks. Glyphosate exerted two significant effects of stimulation and inhibition on the rate of the decay of stem segments of three plants at certain treatments of dose and time.