浙北稻麦连作区稻田糠稷发生对水稻生长的影响及对除草剂敏感性研究

调研了浙北稻麦连作区稻田糠稷发生及分布状况,并考察了糠稷种子萌发特性和对水稻生长的影响及植株对不同除草剂的敏感性,旨在为有效防治糠稷提供参考。结果表明,糠稷在浙北稻麦连作区直播田发生的相对优势度在0~2.8%、机插田发生的相对优势度在0~3.6%;糠稷种子在光照条件下才能萌发,光照36℃（12 h）/黑暗28℃（12 h）条件下,浓度为1 000 mg/L、500 mg/L的GA3溶液和浓度为0.2%、0.1%的NaOH溶液浸种24 h,糠稷的发芽率超过90%,较清水处理差异显著,说明糠稷种子存在休眠特性;田间糠稷发生密度越高,对水稻株高抑制率和水稻减产量越明显,当糠稷密度达125株/m²时,对水稻株高抑制率达4.17%,水稻减产率达61.42%;低龄或高龄糠稷植株对恶唑酰草胺和敌稗·丁草胺二种除草剂均较为敏感,低龄糠稷植株对五氟磺草胺较为敏感。

Study on the Effects of the Occurrence of Panicum bisulcatum Thunb. on Rice Growth and Sensitivity to Herbicides in Paddy Fields in Rice-wheat Rotation Area of Northern Zhejiang

The occurrence and distribution of Panicum bisulcatum Thunb. in paddy fields in the rice-wheat continuous cropping area of northern Zhejiang were investigated. In order to provide reference for effective control to P. bisulcatum, the germination characteristics of seed, it's effects on rice growth and the sensitivity of P. bisulcatum plants to different herbicides were tested. The results showed that the relative abundance of P. bisulcatum was 0 to 2.8% in direct seeding fields and was 0 to 3.6% in machine transplanting fields. P. bisulcatum seeds could not germinate without light. The seeds germination rate was more than 90% immersed in GA3 with 1000 mg/L、500 mg/L or in NaOH with 0.2%、0.1% concentration for 12 h under the condition of 36℃（light 12 h）/28℃（dark 12 h）. There were significant differences compared with immersing clean water under same condition, which indicated that P. bisulcatum seeds had dormancy characteristics. The higher density of P. bisulcatum, the more obvious inhibition rate for the rice plant height and yield. The rice plant was reduced by 4.17% and the yield was reduced by 61.42% compared to the CK while the density of the P. bisulcatum was 125 per square meter in paddy field. Small or large P. bisulcatum plants were sensitive to metamifop and propanil Butachlor, however only small P. bisulcatum were sensitive to penoxsulam.