Response of Mungbean to the Residual Toxicity of Herbicides Used in Wheat under Strip Tillage System

The residual effect of eight herbicides (Pendimethalin, Pretilachlor, Triasulfuron Ethoxysulfuron, Pyrazosulfuron Ethyl, Carfentrazone – ethyl, Carfentrazone – ethyl+ Isoproteuron, 2, 4 –D) used in wheat of Agronomy Field Laboratory during March to June 2014 was evaluated for mungbean. The eighteen herbicide treatment combinations of the eight herbicides were used in wheat. The experiment was conducted in Random Complete Block Design (RCBD) with three replications. The effect of herbicide residues on the mungbean was evaluated in term of germination, seedling root and shoot length, leaf chlorophyll content and seeding dry matter. The result showed that seedling establishment of mungbean was not adversely affected by the herbicides applied the previous wheat crop. Also, the residue of herbicides applied in strip-tilled wheat did not show any adverse effect on germination, shoot length and seedling dry matter of mungbean and even shoot growth of mungbean was not inhibited by the residue of those herbicides. The reason might be related to the half-life and rate of degradation of herbicides in soil. In addition, farmers can easily grow mungbean in a cropping pattern as a subsequent crop of wheat because the study ensures that tested herbicides did not show any adverse residual effect on the establishment of this succeeding crop. However, continuous use of same herbicide or different herbicides with same mode of action in the same land year after year is strictly prohibited. Also, the prudent use of chemical/herbicide is essential to fulfill the goals of conservation agriculture by having reducing detrimental environmental impact as well as reducing herbicide resistance development in crops.