Response of cotton (Gossypium hirsutum) to organic amendments and weed-management practices

A field experiment was conducted during 2015–16 and 2016–17 at Department of Agronomy, TNAU, Coimbatore, Tamil Nadu to determine the effects of organic amendments and weed-control methods on weed control, yield and fibre quality of cotton (Gossypium hirsutum L.). Different organic amendments included (farmyard manure, vermicompost, composted poultry manure and goat manure), while weed-control methods comprised manual weeding, twin wheel hoe weeder and power-operated weeder for improvement in growth and yield of cotton. The results of pooled data indicated that, composted poultry manure along with hand-weeding twice at 20 and 45 days after sowing (DAS) recorded significantly lower weed density (27.29 No./m²), higher weed-control efficiency (84.80%) and higher crop dry-matter production (4,637 kg/ha), sympodial branches/plant (19.74), fruiting points/plant (54.01), bolls/plant (20.87), seed-cotton yield (1,602 kg/ha) compared with the other treatments. Application of organic materials along with manual weeding significantly improved available nutrient content, soil micro-bial biomass carbon, decreased soil electrical conductivity in short-term, and resulted in higher cotton yield and higher soil organic matter content. These results indicated that, application of composted poultry manure in addition with hand-weeding or weeding with power-operated weeder would do more to improve soil organic matter content, increase soil organism abundance, reduce weed population and improve seed-cotton yield.