Synergistic effect of urea and pendimethalin on Eleusine indica suppression and rice growth performance in an aerobic rice system

Abstract

Eleusine indica is one of the most problematic weeds in aerobic rice systems in many countries. A pot study was conducted to evaluate the phytotoxic effect of urea fertiliser and pendimethalin on E. indica, while observing aerobic rice tolerance level and agronomic performance with the application rate. Four treatments were evaluated which were control (urea only without pendimethalin), and three rates of pendimethalin (0.25, 0.50, and 1 kg ai ha^-1) in combination with optimum urea fertiliser (240 kg ha^-1). Results demonstrated that banded application of urea and pendimethalin gave positive response in suppressing E. indica over control. A 0.50 kg ai ha^-1 pendimethalin + 240 kg ha^-1 urea and 1 kg ai ha^-1 pendimethalin + 240 kg ha^-1 urea gave significant suppression on the emergence and seedlings growth of E. indica with 60 - 90% inhibition relative to the control. The aerobic rice growth performance was highly stimulated and the grain yield production was higher for treatments of both 0.50 kg ai ha^-1 and 1 kg ai ha^-1 pendimethalin. These results imply that a lower application rate of 0.50 kg ai ha^-1 pendimethalin + 240 kg ha^-1 urea can be adopted to control E. indica effectively while enhancing the growth performance of aerobic rice plants since it is cost saving and reliable.