Effect of live mulching with annual legumes on performance of maize (Zea mays) and residual effect on following wheat (Triticum aestivum)

摘要

A field experiment was conducted at Selakui, Dehradun during 2001 to 2004 to study the effect of in situ grown live mulching with legumes viz. sunnhemp (Crotalaria juncea L.), dhaincha (Sesbania aculeata Pers.) and cowpea [Vigna unguiculata (L.) Walp.], besides weed mulching at 30 and 45 days of maize (Zea mays L.) growth on moisture conservation, crop productivity and soil properties in maize wheat (Triticum aestivum L. emend Fiori & Paol.) cropping system. Legume mulching accumulated 1.09-1.17 t/ha dry biomass and added 27.9-31.3 kg N/ha compared with 1.31 t/ha biomass and 10.3 kg N/ha with weed mulching at 30 days; which increased further by 68.5-74.8% when applied at 45 days. Maize productivity was 5.6-8.8% higher with legume mulching at 30 days when compared with no mulching. Soil moisture content (0-15 and 15-30 cm depth) at maize harvest increased by a magnitude of 1.63-2.91% due to live mulching, and the effect of sunnhemp was relatively more pronounced than other materials. Wheat yields increased by 13.3-14.0% due to legume mulching in previous maize following enhanced soil moisture and nutrient conservation. Mulching with weed biomass was inferior to legume mulching in both the crops. Mulching at 45 days adversely affected maize growth and yield but was more beneficial to the following wheat due to addition of greater biomass and N. The yield performance of wheat was lower when mulching with cowpea stover was done at maize harvest or wheat sowing, as well as under minimum tillage compared with conventional tillage conditions. Wheat gave 2.5-3.0 folds more net returns than maize, and the net B : C ratio of the system was >1.0 with live mulching of sunnhemp and dhaincha. There was an improvement in organic C and total N, and a decrease in bulk density with a corresponding increase in infiltration rate due to mulching at the end of 3 cropping cycles. It was concluded that live mulching with legumes in maize was beneficial for improving soil moisture conservation, productivity, profitability and soil health in rainfed maize-wheat cropping system under Doon valley conditions.