Residual activity of glyphosate in three soil types on germination and establishment of mung beans

Glyphosate is a type of herbicide applied in field to control weeds throughout the planting season without remaining a long time in soil to affect crop growth. The common trade name of glyphosate is Roundup. Glyphosate is foliar applied translocated herbicides that kill weeds by blocking the formation of amino acid which stops growth of the plant development. Weeds that are exposed to glyphosate show symptoms of stunted growth, yellowing and wrinkling of leaves in seven to ten days. Glyphosate is immobile in soil due to its strong absorption to soil once in contact which resulted in minimum or no residual activity in soil. This study assesses the residual activity of glyphosate on the germination and establishment of mungbeans in three soil types of Bris Soil, River Alluvial Soil and Sandy Clay Soil at various seeds sowing days up to 14 days after soil applied with glyphosate. Mungbeans were grown for 90 days in three soil types and the plant response in growth performances was used to assess the soil residual activity of glyphosate by comparing to controls where the soils were not being applied with glyphosate.The assessments in relation to plant appearance, plant height, number of green leaves, days of flowering, periods of flowering till pod production, number of pods per plant, fresh weight of pods, number of seeds per pod and fresh weight of plant at final recording did not indicate any adverse effect of gyphosate on germination and establishment of mungbeans grown at different days of seed sowing. Germination and seedling development of mungbeans were 90% normal in three soil types irrespective of immediate or late seed sowing to soil applied with glyphosate indicating the absence of significant residual activity hat can influence the crop growth. Mungbeans can be seeded immediately in soil treated with glyphosate but it is recommended to sow seven days after spraying to allow better prospect of growth and survival with proper hand weeding control since glyphosate does not possess any residual weed control.