WEED FLORA, WEED SEED BANK AND PRODUCTIVITY OF RICE–MAIZE CROPPING SYSTEM AS INFLUENCED BY TILLAGE AND WEED MANAGEMENT PRACTICES IN CHHATTISGARH, INDIA

Abstract

A field experiment was conducted during the rice–maize cropping seasons of 2015-16 and 2016-17 at the Instructional cum Research Farm, Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh, to evaluate tillage and weed management practices on weed dynamics, weed seed bank and yield of rice (Oryza sativa L.) and maize (Zea mays L.). The experiment was laid out in a split plot design with 3 replications. Treatments comprised 5 tillage practices in the main plots: CT – CT, CT – ZT, ZT – ZT, CT – ZT and CT – CT, and 3 weed management practices in the sub plots: oxadiargyl 90 g ha⁻¹ PE fb pinoxsulam 22.5 g ha⁻¹ PoE in rice and atrazine 1.0 kg ha⁻¹ PE in maize; pyrazosulfuron + pretilachlor 10 kg (G) ha⁻¹ PE fb bispyribac-Na 25 g ha⁻¹ PoE in rice and halosulfuron 60 g ha⁻¹ PoE in maize; and an unweeded control. Both tillage and weed management practices exerted a significant influence on weed growth rate, weed seed bank and crop yield. Weed growth rate was lowest under CT – CT in rice and ZT – ZT in maize, and highest in the unweeded control. Weed seed numbers increased in the second year and declined with soil depth, being highest under ZT–ZT and lowest under CT–CT at 0–5 cm. Among weed management practices, oxadiargyl 90 g ha⁻¹ PE fb pinoxsulam 22.5 g ha⁻¹ PoE in rice and atrazine 1.0 kg ha⁻¹ PE in maize recorded the highest weed control efficiency (73.2% rice; 93.3% maize) and grain yield (4.98 and 4.51 t ha⁻¹), while the unweeded control produced the least (1.45 and 3.06 t ha⁻¹).