Germination and Root Nodule Formation of Soybean (Glycine max (L.) Merr.) in Ridomil and Chlorpyriphos Treated Soil

Abstract

Germination and root nodule formation of soybean (Glycine max) was evaluated in soil treated with Ridomil (R), Chlorpyriphos (CH), and a Combination of both (COM); using a completely randomized design, and a 3×3 factorial arrangement. Factor 1 was the pesticide type with 3 levels - R, CH, and COM; while factor 2 was the contamination rate (v/wt) with 3 levels - 0% (control), 2%, and 4%. Aqueous pesticides preparations (as recommended by manufacturers) were applied once, before seeds were planted. More than Ridomil and Combination, significantly (P<0.05) diminished percentage germination due to Chlorpyriphos was observed at 2, 3, and 4 weeks post application. The control had significantly higher germination than 2% and 4% groups, up until the 5th week. The Chlorpyriphos and pesticide Combination groups both had significantly lower root nodule number/plant, than Ridomil. Root nodule number/plant, and nodule biomass/plant were significantly reduced due to pesticide stress at 2% and 4%. Pesticides application at 2% and 4% negatively affected germination and root nodule formation; but there was no indication of an enhanced effect due to pesticides combination.