Effects of Diuron Residues on the Growth Performance of Jute (Corchorus. olitorius) Plant and Its Rhizosphere Soil Microbial Population

Abstract

Soil applied herbicides may persist to adversely affect rotational crops as well as perturb soil microbiological functions. This experiment therefore aimed at determining the effects of soil residual activity of diuron (3,4-dichlorophenyl)-N,N-dimethylurea) on Corchorus olitorius plants and on soil microbial population. Diuron herbicide was applied to potted soils at varying times of 12, 9, 6, 3 and zero weeks before planting Corchorus olitorius. Seed germination, seedling mortality, plant growth as well as soil microbial populations were determined. Results indicated that diuron, regardless of time of application significantly reduced growth parameters of C. olitorius plants few days after emergence, and this was followed by 100% die-back in the herbicide treated pots. Results further showed a reduction in soil microbial population with diuron application, and the reduction was inversely related to time of diuron application before sowing C. olitorius. Sensitive vegetables such as C. olitorius should not be sown to succeed a short season crop in which diuron had been applied to control weeds at the usual recommended rate of 3.0 kg a.i/ha. Allowance of a fallow period following the first crop might also help the soil microbial community to recover from diuron toxicity.