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Weed management in maize (Zea mays L.) through allelopathy

Mahmood, Azhar (2010) Weed management in maize (Zea mays L.) through allelopathy. PhD thesis, University of Agriculture, Faisalabad .

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Abstract

The present research work was carried out during 2006 and 2007 to manage weeds in maize through allelopathy. In the laboratory trials, combined effect of allelopathic plant water extracts (sorghum, brassica, sunflower, maize, rice and mulberry) on germination and growth of horse purslane was evaluated. Three sets of field experiments were conducted. In first field experiment, allelopathic plant water extracts as sorghum, brassica, sunflower, maize, rice and mulberry were tank mixed with 1/3rd dose of the atrazine. In second experiment, allelopathic crop residues as sorghum, sunflower, rice and maize were surface mulched.Third experiment included intercropping systems as dwarf sorghum, dwarf sunflower and mungbean in one or two rows in maize. Results showed that higher concentration (100%) of sorghum+sunflower water extracts used as foliar spray, suppressed horse purslane shoot length by 62-67% and shoot dry weight by 75-89% in both the trials conducted in pots. While in first field experiment sorghum+brassica+sunflower water extracts each at 18 L ha-1 tank mixed with atrazine at 0.167 kg a.i. ha-1 suppressed total weed dry weight by 76-79% at 45 DAS during 2006 and 2007, respectively and increased maize grain yield by 50% over control and was comparable to label rates of both herbicides i.e. s-metolachlor+atrazine and atrazine alone in reducing weed dry weight and enhancing maize grain yield and also had highest MRR (7051 and 7244%) during 2006 and 2007, respectively. In the second experiment, surface mulching of rice+sunflower+maize residues each at 6.0 Mg ha-1 suppressed total weed dry weight by 71-84% at 45 DAS during 2006 and 2007, respectively. Aforementioned treatment also enhanced maize grain yield (60% over control) and was comparable to smetolachlor+ atrazine at label rate (63% over control). All mulch treatments were uneconomical due to high cost and low net benefits. In the third experiment, intercropping of two rows of sorghum, sunflower and mungbean were more effective than one row in reducing weeds. Different intercropping systems suppressed maize grain yield by 6 to 38%.Hand hoeing resulted in 67% higher maize grain yield over weedy check. In conclusion, foliar application of sorghum+sunflower+brassica extracts each at 18 L ha-1 combined with 1/3rd dose of atrazine (0.167 kg a.i. ha-1) was the most effective and economical treatment with good net benefits and highest marginal returns, hence label dose of herbicide can be reduced by 67%.

Item Type:Thesis (PhD)
Uncontrolled Keywords:Weed, Extracts, Yield, Grain, Maize, Through, Sunflower, Conducted, Allelopathy, Intercropping, Zea, Treatments, Effective, Economical
Subjects:Agriculture & Veterinary Sciences(a) > Agriculture(a1)
ID Code:6922
Deposited By:Mr. Javed Memon
Deposited On:11 Aug 2011 12:32
Last Modified:11 Aug 2011 12:32

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