Research On Technology Of "Two Segments Method" Against Weeds In Direct-Sowing Rice Fields

Because of direct sowing rice can save money, time and keep production at stable level, the area of rice field that made use of this planting technology is increasing in nowadays. But this kind of technology is proper for weeds growth, so the weeds had been the main reason on the way of direct sowing technology development. In order to control weeds in direct sowing rice field and improve the safety of herbicide to rice, some studies that had listed below had been finished:1. The IC₅0 and IC₁0 of Acetochlor, Butachlor, Metolachlor, R(-)-Napropmam had been measured when these herbicides applied alone, and the IC₅0 and IC₁0 of these herbicide mixed with Bianhuanglong respectively had been calculated. The sequence of safety that these four herbicides applied alone is R(-)-Napropmam, Butachlor, Metolachlor, Acetochlor. When these herbicides mixed with bensulfuron-methy at the best ratio respectively, Acetochlor can increase safety 3.3 times, Butachlor can increase 0.74 times, Metolachlor and R(-)-Napropmam are 0.7 times and 0.72 times respectively. These data showed Bianhuanglong can reduce the toxicity of these four herbicide to rice.2. This paper had experimented the additional-effect of promoter SDP Hailiping Jiabeisha and tea saponin to the mixture of Quinclorac and Bianhuanglong in laboratory and field. In laboratory experiment, the controlling effect data to Echinochloa crusgalli(L) Beauv. showed that all of these four promoter can increase the controlling effect of mixture of Quinclorac and Bianhuanglongto Echinochloa crusgalli(L) Beauv . The best value of these four promoters add to mixture are below respectively: SDP is 5 gram per 667m², Hailiping 10 gram per 667m² , Jiabeisha6 gram per 667m². Field nails have got the same trend and the data are Jiabeisha6 gram per 667m² , SDP 5 gram per 667m² and Hailiping 10 gram per 667m² respectively. According to cost, effect and manufacture, SDP is the most proper promoter.3. According to effect of different style herbicide in controlling weeds in directsowing rice field, the best project is that make use of 50% Quinclorac 25 gram per 667m2 and 10% Bianhuanglong per 667m2 and SDP 5 gram per 667m2 during one leave stage of rice and apply 30% R(-)-Napropmam 15 gram per 667m2 and 10% Bianhuanglong 5 gram per 667m2 during three leaves stage of rice.