Study On Weed Gontrol In New Established Turf Of Zoysiagrass And Three Cool-season Turfgrasses

Since middle 1990s of last century, the turfgrass industry has got fast development inour country. By now, it is becoming a prosperous industry. However, the research of turfweed control in this country can't match with the industry, especially that of weed controlin seedlings.Controling weeds effectively are the key of esteblishing turf successfully.Turf established by seed is desirable because of minimum establishment costs.But it is very difficult to control weeds during turfgrass seeding, especially init that has long period of emergence and slow growth of seedlings and issowed at the same time with weeds emergency. At present, in our country, itrelies mainly on picking up to control weeds after turfgrass seeding. There aremany methods to control weeds in turf, but the most convenient, effective andeconomical means is to adopt chemical herbicides. Internationally, moreresearches are concentrated on mature turf, but relatively less on seedlings.Zoysiagrass can endure drought, leanness, trample, diseases and pests, andhas strong adaptability and can be maintained with minimal cost, so it is afavourite of people. But because of the relatively higher emergencetemperature, slow seedlling growth and the same emergence time withsummer weeds, zoysiagrass turf is difficult to be established by seeding. It hasalready become one of the main barriers of zoysiagrass apllication.The research chooses several kinds of possible herbicides and, on the basisof the results of potted and field experiments, analyzes the effects of them onthe turfgrass and on the chemical control of weed to select the suitedherbicides and to seek the techniques of weed control at seedling stage ofzoysiagrass. In addition, quinclorac, new-type herbicide in turf, is also studiedsystematically on the safety to several cool-season grasses. The result shows:(1) The optimum herbicides are quinclorac, xiaosuo (a trial herbicide), dicamba, fenoxyprop-p-ethyl and oxadizaon. But MCPA-Na, 2,4-D butylate and penoxalin is not applicable to zoysiagrass seedlings.Quinclorac caused less herbicide injury to zoysiagrass seedlings. It can be applied immediately following seeding as a pre-emergence herbicide or at least 35 days after seeding as a post-emergence one.In order to control broadleaf weeds, especially purslane, xiaosuo and dicamba can be selected. But they must be applied at 0.30 kg/hm~2 and 48 %AC 0.30 L/hm~2 respectively 35 days late after seeding. Xiaosuo is more effective and safer than dicamba.Fenoxyprop-p-ethyl should be applied at least 49 days after seeding...