Integrated Weed Management for Enhanced Growth and Yield of Grain Amaranth

Abstract

Weed infestation is a major constraint in grain amaranth because the crop grows slowly during its early stages and remains vulnerable to competition for light, moisture, nutrients and space. A three-year field experiment was conducted during the rabi seasons of 2022-23 to 2024-25 at the Instructional Farm, Department of Agronomy, Navsari Agricultural University, Navsari, to evaluate integrated weed management practices for weed suppression, crop growth, yield and economics of grain amaranth (Amaranthus hypochondriacus L.). The experiment comprised ten treatments arranged in a randomised block design with three replications. Treatments included unweeded control, weed-free maintenance at 20, 40 and 60 days after sowing, interculturing followed by hand weeding, sugarcane trash mulch, stale seedbed-based practices and pre-emergence pendimethalin treatments, either alone or combined with hand weeding. The pooled results indicated substantial variation among treatments for weed density, weed dry weight, weed control efficiency, crop growth, yield attributes, yield and economics. Weed-free maintenance at 20, 40 and 60 days after sowing recorded the lowest weed population (12.22 m⁻²), lowest weed dry weight (3.50 kg ha⁻¹), highest weed control efficiency (98.01%) and zero weed index. The same treatment also recorded the highest plant height (131.43 cm), spike length (63.44 cm), number of spikelets per spike (65.67), grain yield (1614 kg ha⁻¹), stalk yield (4598 kg ha⁻¹), net realisation (₹ 94,492 ha⁻¹) and benefit:cost ratio (2.73). Interculturing followed by hand weeding at 20 and 40 days after sowing performed statistically at par with the weed-free treatment for important growth and yield traits. The findings indicate that timely integration of interculturing and hand weeding can provide effective weed management and improve productivity and profitability of grain amaranth under south Gujarat conditions.