Weed control in maize (Zea mays L.) through sorghum allelopathy

Sorghum allelopathy has been utilized as an economical and natural technique for controlling weeds in some field crops like wheat (Tritictum aestivitin L.), maize (Zea maYs L.), rice (Oryza sativa L.), MLingbean (Vigna radiata L.) and Brassica (Brassica juncea L.). It can be used as sorgaab (water extract of mature sorghum plants), sorghum mulch, sorghum soil incorporation or included in crop rotation. Two field experiments were conducted for two years in the summer of 1997 and 1998. In Experiment 1, the response of maize (Zea mays ys L.) and summer weeds to foliar applications of sorgaab, hand weeding and herbicide spray was studied. In Experiment 2, the comparative efficacy of sorgaab at 15, 30 and 45 days after sowing (DAS) and sorghum Mulch for controlling weeds were studied. Sorgaab foliar spraying controlled from 18-50% weeds and increased maize grain yield by 11-44%. Mature and chatred sorghum herbage (10-15 Mg ha(-1)) surface applied at sowing controlled up to 26-37% weeds and increased maize yield by 36-40%. Three foliar sprays of sorgaab at 15, 30 and 45 days after sowing was the most economical method for controlling weeds in maize as compared with hand weeding, chemical herbicides and sorghum mulch. Weed control through hand weeding and/ or chemical herbicides was found to be economically impractical due to higher costs involved in both cases. Sorgaab can be used as a natural weed inhibitor in maize. (C) 2004 by The Haworth Press, Inc. All rights reserved.