作 者 ：李儒海,强胜*,邱多生,储秋华,潘根兴
期 刊 ：生态学报 2008年 28卷 7期 页码：3236~3243
关键词：长期施肥；杂草物种多样性；杂草群落；水稻-油菜轮作制；
Keywords:long-term fertilization, weed species diversity, weed community, rice-oilseed rape cropping system,
摘 要 ：为揭示长期不同施肥方式下农田生态系统中杂草群落的变化规律, 于2006年10月在太湖地区一个长期肥料试验定位监测田, 运用群落生态学方法研究了7种长期不同施肥处理持续20a后对水稻-油菜轮作制水稻田杂草群落的影响。试验区共记录到杂草11种，隶属于6个科。其中，节节菜（Rotala indica）、陌上菜（Lindernia procumbens）、鸭舌草（Monochoria vaginalis）、异型莎草（Cyperus difformis）等4种杂草在所有施肥处理区发生密度较大。莎草科杂草牛毛毡（Eleocharis yokoscensis）只在不施肥区和纯氮肥区出现，而球穗扁莎（Pycreus globosus）和萤蔺（Scirpus juncoides）仅在不施肥区出现。长期不同施肥措施下，田间杂草群落的物种多样性有明显差异：全年秸秆区的物种丰富度（7.3种）最小，不施肥区（10.7种）最大；不施肥区、常规区、秋季秸秆区Shannon-Wiener指数显著大于其他处理区；不施肥区和常规区Simpson指数显著小于其他处理区；不施肥区和纯氮肥区Pielou均匀度指数显著小于其他处理区。田间杂草群落的优势种组成也发生了一定变化， Whittaker指数表明，与不施肥处理相比，单施化肥、化肥配施猪粪对杂草群落结构及物种组成的影响最显著，化肥配施油菜秸秆和化肥配施油菜水稻秸秆次之，而纯施氮肥和化肥配施水稻秸秆的影响较小。Srensen群落相似性指数及聚类分析结果也得到相似的结论。结果表明，单施化肥（平衡施用N、P、K肥）、化肥配施猪粪、化肥配施夏季、秋季和全年秸秆处理均能显著改变田间杂草群落的组成, 改变某些杂草在群落中的优势地位, 从而抑制其发生危害程度。
Abstract:The effects of long-term fertilization regimes on weed communities were evaluated in a rice-oilseed rape cropping system in Tai Lake region of Jiangsu Province. The fertilization treatments were: no fertilizer (NoF), N fertilizer (NF), chemical fertilizer (CF), chemical fertilizer plus pig manure (CFM), chemical fertilizer plus oilseed rape stalk (CFO), chemical fertilizer plus rice straw (CFR), and chemical fertilizer plus oilseed rape stalk and rice straw (CFOR). For each treatment there were three replicated plots and treatments were maintained for 20 years. The amount of fertilizer applied per year was 427.5 kg/hm2 N as urea, 45 kg/hm2 P2O5 as super phosphate, 54 kg/hm2 K2O, 2250 kg/hm2 (fresh weight) oilseed rape stalk and/or rice straw, and 16800 kg/hm2 pig manure (fresh weight) for the respective treatments. In October 2006, the number, coverage, and aboveground fresh weight of each weed species present in five 1-m2 quadrats per plot were determined. A total of 11 weed species from 6 families were recorded. Of these, Rotala indica, Lindernia procumbens, Monochoria vaginalis and Cyperus difformis had high population densities under all fertilization treatments. The sedge weed Eleocharis yokoscensis was found only in the NoF and NF plots, while Pycreus globosus and Scirpus juncoides were found only in NoF plots. The weed species richness varied significantly among different fertilization treatments, ranging from 7.3 in CFOR to 10.7 in NoF. The composition and abundance of weed species also differed in different fertilization treatments. The Shannon-Wiener index for the NoF, CFM and CFR treatments was significantly higher than that of the other fertilization treatments. The Simpson dominance index in the NoF, CFM treatments was significantly lower than that of the other fertilization treatments. The Pielou evenness index in the NoF and NF treatments was significantly lower than that of the other fertilization treatments. Based on the Whittaker index, the CF and CFM treatments had the greatest, and the CFO and CFOR treatements the second greatest, effects on weed community composition. Whereas, the NF and CFR treatments had no significant effect on community composition as compared to the NoF treatment. The Srensen similarity index and clustering analysis gave similar results as the Whittaker index. The results indicate that the application of a balanced N, P, K fertilizer with or without organic manure (pig manure and/or crop straw) allowed for all weed species present to thrive, thus maintaining weed species diversity as a result of no one species becoming dominant.
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