Investigating of Increasing Glyphosate Herbicide Efficiency with Nitrogen in Control of Tea weeds

ABSTRACT: To determine the efficacy of Glyphosate plus Ammonium sulphate and urea on tea weeds , field trials was conducted in spring 2008 in range lands of Guilan province (Ezbaram kashef, (Ezbaram kashef,this area is under the tea research instute of Iran).) of Iran. This experiment was conducted in completely randomized block design with four replications. Treatments consist of Glyphosate 2, 4, 6 and 8 lit/ha with and without Ammonium sulphate and urea (6kg/ha) plus hand weeding at 2 and 4 week intervals. Main weeds found during investigation, were Acalipha austrialis, ،Solanum nigrum, digitaria ،Sanguinalis, Oplismenus compositus, Convulvulus arvensis,ِِ Amaronthus retroflexus, Potentilla reptans, Oxalis corniculata, Echinochloa crusgalis and Paspalum disticum. All treatments were evaluated on weed growth (percentage of dry material and density) and tea crop and quality 15 and 30 days after treatment (DAT). The results showed that all herbicide treatments in applied rates significantly reduced weed density and dry matter in comparison with hand weeding. There was significant difference in tea crop among treatments. The results of experiments showed that (Glyphosate+ Ammonium sulphate) (2 lit\ha + 6 kg/ha) was safe when applied around the collar of the bush and the treatments had no adverse effect on tea crop and quality. Therefore it can control most tea weeds.