Efficacy, selectivity and economics of metolachlor for weed controlin maize (Zea mays) and its effect on succeeding chickpea (Cicer arietinum)

Abstract

The inverse correlation between maize (Zea mays L.) yield and weed density has been well-established over time. Among the various weed management strategies, chemical control is recognized as the most efficacious. An experiment was conducted during 2019 and 2020 at Agriculture Research Sub-Station (Agriculture University, Jodhpur, Rajasthan), Sumerpur, Pali, Rajasthan to evaluate superiorr effectiveness of metolachlor @1000 g a.i./ha and 1200 g a.i./ha in managing broad-leaved weeds and certain grass species, when compared to atrazine applied at 1000 g a.i./ha, in maize cultivation. The maize variety ‘PHM-4’ was selected for the study. The experiment was laid out in a randomized block design (RBD) having three replication. This resulted in a total weed control efficiency of 63.4% and 61.3% across all crop growth stages. However, it's worth noting that a higher dose of metolachlor at 2000 g a.i./ha showed signs of phytotoxicity on maize, which eventually recovered within 15–20 days post-herbicide treatment. The study concluded that metolachlor at 1000 g a.i./ha effectively combats broad-leaved and some grassy weeds in maize. Notably, the maximum net return was observed with metolachlor at 1000 g a.i./ha, amounting to ₹35,150/ha and ₹51,496/ha during both years. In the subsequent chickpea phase, no treatment was applied, and phytotoxicity was observed in metolachlor at 2400 g a.i./ha, causing yellowing and stunting of plants.