Effect of weed interference with sugar beet under different nitrogen amounts
Subject Areas : Journal of Plant Ecophysiology
1 - دانش آموخته کارشناسی ارشد دانشگاه آزاد اسلامی واحد سبزوار
2 - استادیار دانشگاه آزاد اسلامی واحد سبزوار
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Abstract :
Yield loss in sugar beet due to weeds is higher than pests and diseases. To investigate the effect of duration of weed interference on quantitative and qualitative yield of sugar beet in different agriculture management systems, an experiment was conducted as split plot design based on randomized complete block design with three replications on Barakat farms Jovain Agricultural and Industrial Company (60 Km southeast of Sabzevar) in 2012-2013. The main factor was Nitrogen amount (100, 200 and 300 kg.ha-1 Low, medium and high, respectively). And weed interference duration (0, 30, 45 and 60 days after emergence include full-season interference of weeds) was as the subplot. Results showed increasing nitrogen, increased dry weight per unit area of weeds, but weed density was not affected by different amounts of nitrogen. The highest root yield sugar yield and percentage of net sugar were derived by application of 300 kg.ha-1 while molasses sugar, α-amino-N and Na+ observed at 300 kg.ha-1. Increasing duration of weed interference reduced root yield (57.2%), sugar yield (83.69%), net sugar (16.01%), Na+(34.54%) K+ (17.37%) and increased alkalinity (11%) compared with those of the control. The highest root yield and sugar yield was observed in the control treatment that hadn't significant difference with 30 days weed interference. Increasing duration of weed interference reduced weed density and increased weed dry weight. In low and high (100 and 300 Kg. ha-1) amounts of nitrogen, sugar beet was less competitive than weeds whereas medium level (200 Kg.ha-1 N) sugar beet was more competitive than weeds. Overall, weed control in 30 days after emergence and use of 200 Kg.ha-1 N was the best treatment.
