长期定位施肥对稻麦轮作农田土壤杂草种子库的影响

【目的】解析长期不同施肥措施下稻麦两熟制农田土壤杂草种子库的异构性及其养分影响因素，为稻麦高产与杂草控制协同的养分管理提供依据。【方法】以太湖地区31年的长期肥料定位试验土壤为材料，采用镜检法对不施肥（CK）、单施氮肥（N）、氮肥加磷肥（NP）、氮肥加钾肥（NK）、磷肥加钾肥（PK）、氮磷钾3种肥料配施（NPK）6个不同施肥处理的表层土壤（0—15 cm）中杂草种子的种类进行鉴定并计数，分析Simpson指数，Shannon指数，Richness指数和Evenness指数，并进行冗余分析和相关分析。【结果】（1）各个处理的鸭舌草、陌上菜、水苋菜、酸模叶蓼、牛毛毡、异型莎草的种子密度都较大，成为危害太湖地区稻麦生长的主要优势杂草种群。（2）氮肥施入使大部分杂草种子数量下降。磷肥施入使牛毛毡种子数量显著下降，鸭舌草种子数量显著增加。（3）NPK处理的物种数及群落丰富度指数最高（P＜0.05），而均匀度指数、Shannon指数和Simpson指数则显著低于其余处理（P＜0.05）。【结论】长期氮、磷、钾肥料单一或配合施用可显著影响稻麦两熟制农田杂草种子库的群落组成，其中施氮显著降低农田杂草种子密度，磷、钾肥则影响了不同杂草种子在各处理中的数量。

Changes in Weed Seed Bank Community of Agricultural Soils in Rice-Wheat Rotation Field Due to Long-Term Fertilization

【Objective】Characterizing the long-term effect of fertilization on weed seed bank community will aid in developing sustainable weed management practices and promoting crop yield.【Method】Weed seed bank was measured within a long-term fertilization from 1980 in the Taihu Lake region. Inorganic fertilizer treatments were selected as follows: CK (no fertilizer), N (N fertilizer), NP (N plus P fertilizer), NK (N plus P fertilizer), PK (P plus K fertilizer) and NPK (N plus P and K fertilizers). Weed seed density and community surveys were conducted and bio-diversity indices including Simpson index, Shannon index, Richness index, Evenness index were also calculated, at the same time, redundancy analysis (RDA) and correlation analysis were executed to mining the relationship between fertilizer management and weed seed bank.【Result】Seed densities of Monochoriav aginalis, Lindernia procumbens, Ammannia baccifera, Polygonum lapathifolium, Eleocharis yokoscensis, and Cyperus were high and dominant in different treatments, these weeds did a lot of damage to the growth of crops. Most of the weed seed densities decreased when nitrogen fertilizer was applied, the density of E. yokoscensis decreased when phosphorus fertilizer was applied while the density of M. aginalis increased. The number of species and richness index of NPK treatment were the highest (P＜0.05), but its evenness index, Shannon index and Simpson index were significantly lower than those of the other treatments.【Conclusion】Long-term fertilization had changed the weed seed bank community in local area. The seed density decreased significantly when nitrogen fertilizer was applied. Phosphorus and potassium fertilizer had effects on the number of different weed species in the field.