无公害水稻生产的病虫草调控技术及其效应的研究

利用无公害农药和农业措施防治水稻主要病虫草试验结果表明,井·腊芽、井冈霉素和多抗霉素在水稻分蘖末期和孕穗末期各喷施1次,对纹枯病防效达75.16%～94.27%,优于化学杀菌剂三唑酮;春雷霉素和灭瘟素在叶瘟病发生初期及破肚期、齐穗期各喷施1次,对叶瘟防效为50.54%～72.67%,穗瘟为76.66%～87.42%,与化学杀菌剂三环唑相当.3种无公害农药在二化螟和稻纵卷叶螟1～2龄幼虫期使用,苏云金杆菌防效优于化学杀虫剂杀虫双,皂素·烟碱和苦参碱与杀虫双相当;皂素·烟碱和苦参碱在稻飞虱1～2龄若虫期使用,药后3～30d防效均在70%以上,低于化学杀虫剂吡虫啉.在水稻移栽前耕地2次,再配合施用适量的未腐熟有机质或人工除草,能控制杂草发生和提高产量.采用无公害农药和农业措施防治水稻病虫草,产量较常规化防区略有增加,稻谷中农药残留量较化防区低,符合绿色食品卫生指标要求.

A survey of heavy-metal content in plants growing on the soil polluted by Manganese mine tailings

A survey of soils and ten plants growing on the soil polluted by Manganese mine tailings in Xiangtan city was conducted.Analysis result indicated that the exceptional-high concentrations of Mn was found to be the limiting factor for plant growth. The concentrations of Mn, Pb, and Cd in the ten plants and Mn-enrichmentalabilities of the ten plants were analyzed in this paper.Poa pratensts, Gnaphalinm affine, Pteris viltata L., and Phytolacca esculenta Van Houtte were proved to have good metal-enrichmental and Mn-tolerant ability. Poa pratensts, Gnaphalinm affine and Pteris viltata L.were Pb-tolerant plants. Comnyza Canadensis (L.) Cronqs, Poa pratensts, and Gnaphalinm affine were Cd-tolerant plants. However, no hyperaccummulators of these three heavy metals were found in the survey. Further research on improved culture experements were still in process.