Physiological studies on the effect of herbicides on growth, nodulation, and grain yield of greengram (Vigna radiata L. Wilczek)

Abstract

A field experiment was conducted at Crop Research Centre of Rajendra Agricultural University, Bihar, Pusa, Samastipur during summer season of 2003 and 2004 in calcareous sandy loam soil to evaluate the effect of different herbicides alone and mixture on physiology, growth and nodulation in greengram. (Vigna radiata (L) Wilczek).The experiment comprised with nine treatments including one water sprayed control and replicated four times under randomized block design. The visual phytotoxicity rating during experimentation showed that the herbicide oxyfluorfen at 0.2 kg/ha, metolachlor at 1.0 kg/ha and pendimethalin at 1.0 kg/ha did not caused phytotoxicity in greengram. Root permeability was maximum in treatment with oxyfluorfen + clomazone (0.1+0.5) kg/ha followed by pendimethalin + clomazone (0.5 + 0.5) kg/ha and minimum with the oxyfluorfen at 0.2 kg/ha. Total dehydrogenase activity (root activity) at root apices was maximum in plot treated with oxyfluorfen at 0.2 kg/ha and minimum in oxyfluorfen + clomazone (0.1 + 0.5) kg/ha treated plot. Specific leaf weight (SLW) was found significantly altered by herbicidal treatment which was found maximum in oxyfluorfen at 0.2 kg/ha treated plot. There was no significant difference observed regarding total number of nodules/ plant, number of pods / plant, and test weight. Maximum grain yield of 3.06 g per plant was recorded in the treatment oxyfluorfen at 0.2 kg/ha but the differences were non significant. In addition, results showed that mixed application of herbicides viz., oxyfluorfen + clomazone (0.1 + 0.5) kg/ha and pendimethalin + clomazone (0.5 + 0.5) kg/ha did not show their good performance under the field condition of north Bihar. Therefore, oxyfluorfen at 0.2 kg/ha, metolachlor at 1.0 kg/ha and pendimethalin at 1.0 kg/ha are the safe herbicides for greengram as well as effective weed control.