Polyethylene mulching for enhancing crop productivity and water use efficiency in cotton (Gossypium hirsutum) and maize (Zea mays) cropping system

Field experiments were conducted consecutively for 2 years at Coimbatore between 2002–03 and 2003–04 crop seasons during winter (August – February). Cotton (Gossypium hirsutum L.) followed by summer (March – May), maize (Zea mays L.) crops using different thickness black polyethylene mulch film of 30, 50, 75 and 100 micron were evaluated against conventionally planted (no mulch) cotton – maize cropping system for moisture conservation and enhanced crop production efficiency. Higher uptake of nutrients due to higher temperature coupled with higher available soil moisture caused significant increase in root cation exchange capacity, nutrient uptake, dry matter accumulation and partitioning of assimilates under polyethylene mulching with an average yield enhancement of 1.83 to 1.90 fold in cotton and 1.95 to 2.10 fold in maize crops besides saving water. The water requirement of mulched cotton was 58.63 ha-cm whereas conventionally grown cotton was 84.19 ha-cm. The water use efficiency of mulched cotton was 43.2 kg/ha-cm as against 16.6 kg/ha-cm for conventionally planted no mulch cotton crop. The poly-mulched cotton-maize system recorded the highest net return (Rs 74,178/ha) and benefit cost ratio (1.68) as against the conventional system (Rs 29,863 and 1.04).