Preceding maize crop herbicide residual effect on germination, growth and vigour of succeeding blackgram

Weeds are the most critical pest, which cause the highest yield reduction in food grain crops. Weeds interfere with maize growth by competing one or more growth limiting factors, controlling of weeds in maize during the critical period assumes great importance for realizing higher yield. Unavailability of relatively cheap labour in time necessitated the use of herbicides in maize. Residual impact of herbicides caused significant influence on germination and growth of succeeding crop.

The field experiment was carried out during kharif 2019 at Agricultural College and Research Institute, Madurai to evaluate the residual effect of herbicides used in preceding maize on succeeding blackgram. Treatments were application of pre emergence herbicide atrazine at 0.25 kg ha⁻¹ or pendimethalin 1 kg ha⁻¹ applied singly on 3 days after sowing and in combination with post emergence herbicide tembotrione 120 g ha⁻¹ or halosulfuron methyl 90 g ha⁻¹ on 25 DAS, weed free check, unweeded check in maize crop.

Among the weed control treatments, pre emergence herbicides atrazine 0.25 kg ha⁻¹ or pendimethalin 1 kg ha⁻¹ singly and in combination with post emergence herbicides tembotrione 120 g ha⁻¹ or halosulfuron methyl 90 g ha⁻¹ applied in maize crop did not caused any phyotoxicity and residual impact on succeeding blackgram. However, the highest plant height (29.5 cm), dry matter production (1.17 g plant⁻¹) and seedling vigour index (1473) of succeeding blackgram was recorded in atrazine at 0.25 kg ha⁻¹ as pre emergence at 3 DAS followed by tembotrione at 120 g ha⁻¹ as post emergence at 25 DAS.