长期不同施肥方式对稻麦轮作田杂草群落的影响

【目的】明确在稻麦轮作条件下，肥料管理对太湖地区稻麦轮作田杂草群落的影响特征和方式。【方法】在水稻收获后，对长期不同肥料处理小区，具体包括不施肥（CK），仅施氮肥（N），施氮钾肥（NK），施磷钾肥（PK），施氮磷肥（NP）和均衡施肥（NPK），进行杂草群落调查。分析杂草密度、多样性指数Shannon-H’，均匀度指数Pielou-EJ和丰富度指数Margalef-DMG，并进行主成分和回归分析。【结果】杂草总密度的排列次序为NP＞CK＞N＞NK＞NPK，稻槎菜，牛繁缕，菵草和大巢菜是主要农田杂草。氮磷养分亏缺提高了杂草多样性，Shannon-H’指数排序为CK＞NK＞PK＞N＞NP＞NPK。主成分1、2的特征值分别为0.498和0.235，稻槎菜，野老鹳草，异型莎草和菵草与主成分1夹角较小，能更多地解释主成分1。对提取的主成分1、2值与土壤有效态氮磷钾回归分析，其中有效氮、磷与主成分1值回归决定系数分别为0.85、0.86（P＜0.05），主成分2值与土壤养分因子无显著相关性。【结论】太湖地区稻麦轮作条件下，土壤养分的盈亏决定了田面杂草密度和优势种群，氮磷亏缺导致杂草群落多样性高于氮磷钾均衡施肥，且土壤氮含量对杂草群落的影响最显著。

Effect of Long-Term Different Fertilization Management on Weed Community in Rice-Wheat Rotation Field

【Objective】 The characters and effects on weed community caused by different long-term fertilization managements was evaluated in rice-wheat rotation field in Taihu Lake region for the purpose of bio-diversity protection, crop yield increase and noxious weeds decrease. 【Method】 Inorganic fertilizer treatments were selected as follows: CK (no fertilizer), N (N fertilizer), NK (N plus P fertilizer), NPK (N plus P and K fertilizer), NP (N plus P fertilizer) and PK (P plus K fertilizer). Weed density and community surveys were conducted, and bio-diversity indices were also calculated, including diversity index (Shannon-H’), evenness index (Pielou-EJ), and richness index (Margalef-DMG). At the same time, principal component analysis (PCA) and regression analysis were executed to mining the relationship between fertilizer management and weeds.【Result】Total weed density order was NP＞CK＞N＞NK＞NPK, and Lapsana apogonoides, Malachium aquaticum, Beckmannia syzigachne and Vicia sativa were dominant species in Taihu Lake rigion. The biodiversity indices were increased when nitrogen and phosphorus was deficient, and especially, Shannon-H’ index order was CK＞NK＞PK＞N＞NP＞NPK. The eigenvalue of principal components F1 and F2 were 0.498 and 0.235, respectively. L. apogonoides, Geranium carolinianum, Cyperus difformis and B. syzigachne could illustrate more about F1, since the angels were small between F1 and these weeds arrows. The regression coefficients of determination were 0.85, 0.86 (P＜0.05), which analyzed between the value of F1 and soil available-N and Olsen-P, respectively, and there was no significant relationship between F2 and soil nutrient in eigenvalue.【Conclusion】The weed density and dominant species in rice-wheat rotation field were limited by soil nutrient, the biodiversity indices of weed community were higher when soil nutrient was not so sufficient, and weed community was affected sensitively by available-N.