中央高校基本科研业务费专项（2662018YJ024）； 国家重点研发计划专项（2018YFD0301304）； 湖北省生态循环农业创新体系项目
为探究稻虾共作对稻田杂草群落组成及物种多样性的影响，运用植物群落生态学的方法，通过调查区域在1 a（RC1）、2 a（RC2）、4 a（RC4）和9 a（RC9）等4个不同稻虾共作年限稻田和1 a小区控制试验稻田(CK)田面和田埂杂草物种数变化、杂草数量变化以及杂草盖度变化，研究不同稻虾共作年限稻田杂草的群落变化特点及控草效果。结果显示：稻虾共作稻田的杂草生物多样性指标随年限增长表现出先降低后增加的趋势，CK的Simpson指数和Shannon多样性指数杂草优势度显著高于稻虾处理，RC4处理最低。Pielou均匀度指数RC9处理显著高于其他年限稻虾田，但与CK处理无显著差异。随稻虾共作年限的增加，稻田杂草总数表现出先降低后增加的趋势，均显著低于CK处理。不同种杂草的重要值（importance value,I值）随稻虾共作年限增长呈现不同的规律，千金子、稗草、双穗雀稗和飘拂草的I值随年限增加先降低后增加，通泉草、空心莲子草、鳢肠、鸭舌草等的I值在稻虾共作稻田中表现出小于水稻单作稻田并逐年降低的规律。在大田控制试验中，经过1 a稻虾共作模式后，稻田田内和田埂的杂草物种数、杂草个体数和盖度均显著降低。结果表明：短期稻虾共作对稻田杂草的抑制作用明显，长期的稻虾共作会逐步形成新的杂草群落结构，需要采取对应的杂草防控措施。
In order to explore the influence of ricecrayfish ecosystems on weed in paddy fields,the characteristics of weed community changes and grass control effect in paddy fields with different years of ricecrayfish ecosystem were studied with ecological approaches to plant communities. This paper studied the differences of weed diversity between rice monoculture and ricecrayfish coculture in 1 year,2 years,4 years and 9 years. Field experiments were conducted to investigate the changes of weed species,weed quantity and weed coverage in fields and ridges after a complete 1year ricecrayfish coculture system. The results showed that the indexes of weed biodiversity in ricecrayfish coculture systems had a trend of decreasing first and then increasing with the increase of years. The Simpson index and Shannon diversity index under CK treatment had the highest weed dominance,which was significantly different from ricecrayfish treatments. The RC4 treatment had the lowest weed dominance. The evenness index of Pielou treated by RC9 has the highest evenness,which is not significantly different from that of CK but significantly different from that of other treatments. The total number of weeds in the sample plots with different years of ricecrayfish coculture system decreased first and then increased with the increase of the number of years,which were significantly lower than those treated with CK. The importance values (I values)of different weeds had different regularities with the increase of ricecrayfish cocultivation years. The I values of Leptochloa chinensis，Echinochhloa crausgalli，Paspalum paspaloides and Fimbristylis dichotoma decreased first and then increased with the increase of years. The I values of Mazus japonicus，Alternanthera philoxeroides，Eclipta prostrata and Monochoriav aginalis in ricecrayfish cocultivation paddy fields were smaller than those in rice monoculture paddy fields and decreased year by year. After 1 year ricecrayfish coculture farming，the number of weed species,weed individuals and weed coverage in the paddy field and the ridge were significantly reduced. The results showed that shortterm ricecrayfish coculture significantly improved the weed control effect. Longterm ricecrayfish coculture gradually formed a new weed community structure,and corresponding weed control measures need to be taken.