不同施肥方式对稻麦轮作制稻田杂草群落的影响

摘要

The effects of several fertilizers(pure chemical fertilizer,organic manure with chemical fertilizer,straw returning with organic and inorganic fertilizer ,organic and inorganic compound fertilizer)on weed communities in rice fields were determined under a rice-wheat cropping system during four consecutive years at Nanjing Agricultural University in Jin-tan.A survey of weed species,density,height and diversity index was conducted before the rice harvest in 2014 to analyze the relationship between the weed population distribu-tion and the fertilizer used. Echinochloa crusgalli, Monochoria vaginalis,Ammannia multiflora,A.baccif-era and Lindernia procumbens were the main weed spe-cies in all the treatments. Long -term fertilization could reduce the occurrence and density of some weed species.The number and density of broadleaf and Cyperaceae weeds decreased significantly when fertiliz-ers were used,but their height increased significantly;the density and height of grassy weeds were almost unaffected. Straw returning with chemical fertilizer,organic manure with chemical fertilizer,organic and inorganic compound fertilizer+urea fertilization for head sprouting and pure chemical fertilizer treatment reduced species diversity index but increased the weed dominance index and lowered the evenness index,easily caused serious harmfulness.Straw returning with once-ap-plied organic and inorganic fertilizer ororganic and inorganic compound fertilizer treatments had higher species diversity index and evenness index,lower weed dominance index and density,complicated weed community structure,and less harmfullness to rice.%为揭示不同施肥（纯施化肥、有机肥配施化肥、秸秆还田配施有机无机肥、有机无机复混肥）对稻—麦两熟制区稻田杂草的影响，以南京农业大学连续4年固定施肥金坛试验田为材料，于2014年水稻收获前进行了杂草群落调查，研究不同施肥、秸秆还田水稻田间杂草种类、密度、高度和杂草多样性指数的差异。结果表明：试验水稻田共记录杂草16种，分属7科、11属。稗草（Echinochloa crusgalli）、鸭舌草（Monochoria vaginalis）、多花水苋（Ammannia multiflora）、水苋菜（A．baccifera）、陌上菜（Lindernia procumbens）广泛分布于各试验田块。长期施肥可减少稻田杂草种类及发生密度。其中阔叶杂草和莎草科杂草在试验设定的各施肥措施下其种类和密度均显著下降，但株高显著增加；禾本科杂草种类、密度和株高几乎不受影响。秸秆还田配施化肥、有机肥配施化肥、有机无机复混肥＋穗肥尿素和纯施化肥的田块中，杂草群落多样性指数低、均匀度指数相对较低，优势度指数较高，容易使单一优势杂草种类暴发，造成较严重危害；秸秆还田配施有机肥化肥、有机无机复混肥一次施用的稻田环境中，杂草群落多样性指数较高，均匀度指数较高，优势度指数较低，杂草群落结构较复杂，群落相对较稳定，且杂草密度较低，对水稻的生长危害较轻。