Effect of some herbicides on cellulose decomposition in the soil

Abstract

The effect of simazine (62, 125, 250 and 500 μg/g soil), paraquat (37, 75, 150 and 300 μg/g soil) and 2,4 D (87, 175, 350 and 700 μg/g soil) on cellulose decomposition in two soils (sandy soil and chernozem) was studied. Simazine and 2,4 D were mixed with soil and cellulose (2% powdered cellulose) before humidification, whereas paraquat was introduced into the soil along with water during humidification. The soil receiving no pesticide treatment was the control. The modelled soil samples were incubated in a thermostat at 28 ˚C for 12 weeks. The amount of water that vaporized was added to the soil on a weekly basis. Results showed that simazine rates had a slight inhibitory effect on cellulolytic activity in the tested soils. Only the highest rate of 2,4 D caused a considerable degree of inhibition of cellulose decomposition. Paraquat exhibited a higher level of toxicity compared to simazine and 2,4 D. As even the lowest application rates were several times greater than the rates commonly used in agricultural practice, the herbicides tested, when applied at recommended rates, cannot be inhibitory factors in cellulose transformation in these soils.