越冬橘园蜘蛛群落多样性研究

通过系统调查,湖南省邵阳市越冬橘园蜘蛛群落共有12科22属28种,其中斑管巢蛛(Clubionareichlini)和美丽蚁蛛(Myrmarachaefarmicaria)为优势种。异质性大的越冬橘园蜘蛛群落的多样性指数、丰富度和个体总数均大于异质性小的越冬橘园,越冬橘园蜘蛛群落的多样性指数大小主要由群落物种丰富度和个体总数决定,与均匀度大小无关。     

天水小陇山锐齿栎群落土壤全N分布特征及与生物多样性关系研究

对天水小陇山锐齿栎群落不同演替阶段土壤全N含量进行了分析 ,探讨了土壤全N与群落生物多样性之间的关系 ,结果表明 :随发育阶段土壤全N含量呈稳定的变化趋势。发育中期 ,随多样性指数、均匀度指数、优势度指数的增加 ,全N含量呈“V”型变化趋势 ,随丰富度指数增加 ,全N含量呈逐渐减小趋势 ;发育后期 ,随着多样性指数、丰富度指数、优势度指数的增加 ,全N呈逐渐增加趋势 ,随着均匀度的增加 ,全N变化不明显 ;发育末期 ,多样性指数、均匀度指数、优势度指数趋于稳定 ,土壤全N含量不稳定 ,随丰富度指数的升高 ,全N有先升高后降低的趋势。     

松嫩平原优势种羊草与其主要伴生种芦苇空间分布格局分析

芦苇是松嫩草地优势种羊草的主要伴生种,两者常常形成物种组成比较单一的混生群落或者与其他物种组成羊草 杂类草群落.选择羊草 芦苇混生群落,羊草群落和芦苇群落的交错区进行羊草、芦苇单物种格局分析.结果表明,1)混生群落和交错区中,羊草和芦苇均是以集聚分布的形式存在;2)羊草在混生群落中的格局强度小于交错区中的格局强度,芦苇在2种类型群落中的格局强度没有显著差异;3)除了考虑物种的生物学特性以外,混生群落种内、种间竞争也是影响羊草集聚分布和格局强度的主要因素,交错区中,环境异质性和种间竞争是影响集聚分布和格局强度的重要因子;4)芦苇在混生群落和交错区中格局强度没有明显差异,由此可以判定芦苇的空间分布格局形成主要受植物本身生物学特性的影响.     

基于冗余分析的高寒草原土壤与草地退化关系

在高寒草原退化草地设置研究样地,观测植物群落特征、采集土壤样品、分析土壤物理化学性质,依据数量生态学基本原理,探讨高寒草原退化草地与土壤因子间关系。结果表明:不同退化程度样地沿冗余分析排序图第一排序轴分布,第一排序轴反映草地退化程度的变化;草地植物群落中与第一排序轴负相关且按相关程度大小排序的指标为盖度>地上生物量>地下生物量;第一、第二排序轴能够解释97.1%的土壤因子与草地退化关系;土壤沙砾、p H与第一排序轴正相关,土壤有机碳、土壤含水量、容重、全氮、有效氮与第一排序轴负相关;第一排序轴及所有排序轴所反映的土壤因子均与草地退化之间呈极显著相关关系(P<0.01);不同土壤因子与草地退化之间相关程度不同,土壤有机碳(r=-0.890)、土壤含水量(r=-0.864)、容重(r=-0.847)、全氮(r=-0.836)、有效氮(r=-0.821)等与高寒草原退化相关程度更高且相关关系极显著(P<0.01)。利用退化草地群落特征和土壤因子数据矩阵进行冗余分析能够较好地综合反映土壤因子与草地退化之间的关系及相关程度,土壤有机碳、土壤含水量、容重、全氮、有效氮是反映高寒草原退化的重要土壤指标。     

Sewage sludge processing determines its impact on soil microbial community structure and function

Composting and thermal drying are amongst the most commonly used post-digestion processes for allowing sanitation and biological stabilization of sewage sludge from municipal treatment plants, and making it suitable as soil conditioner for use in agriculture. To assess the impact of sludge-derived materials on soil microbial properties, fresh (LAF), composted (LAC) and thermally dried (LAT) sludge fractions, each resulting from a different post-treatment process of a same aerobically digested sewage sludge, were added at 1% (w/w) application rate on two contrasting (a loam and a loamy sand) soils and incubated under laboratory conditions for 28 days. Soil respiration, microbial ATP content, hydrolytic activities and arginine ammonification rate were monitored throughout the incubation period. Results showed that soil biochemical variables, including the metabolic quotient (qCO₂), were markedly stimulated after sludge application, and the magnitude of this stimulatory effect was dependent on sludge type (precisely LAT > LAF > LAC), but not on soil type. This effect was related to the content of stable organic matter, which was lower in LAT. Genetic fingerprinting by PCR–DGGE revealed that compositional shifts of soil bacterial and, at greater extent, actinobacterial communities were responsive to the amendment with a differing sludge fraction. The observed time-dependent changes in the DGGE profiles of amended soils reflected the microbial turnover dependent on the sludge nutrient input, whereas no indications of adverse effects of sludge-borne contaminants were noted. Our findings indicate that composting rather thermal drying can represent a more appropriate post-digestion process to make sewage sludge suitable for use as soil conditioner in agriculture.     

澳大利亚社区农园的发展及其对我国的启示

在一些发达国家,社区农园向人们提供了接触自然、放松身心的场所,已受到越来越多市民的喜欢。而我国社区农园的发展仍处于探索期,借鉴国外社区农园对于我国社区农园的发展有很大的裨益。对澳大利亚社区花园的发展状况进行了详细介绍。以三个分别位于居住区、校园、公园的社区花园为例,根据案例分析社区农园对孤独人群、老年人、儿童、残疾人这些弱势群体带来的益处,阐明其对人们身心健康的改善以及对社会可持续发展的重大意义。文末根据澳大利亚社区农园发展的成功经验和我国城市发展的现状,提出我国建设社区农园需要面临的挑战。     

布氏乳杆菌和甲酸对青藏高原不同物候期燕麦青贮饲料发酵品质和细菌群落的影响

为探讨布氏乳杆菌和甲酸对青藏高原不同物候期燕麦（Avena sativa L.）青贮饲料发酵品质和细菌群落的影响，本试验以开花期、乳熟期和蜡熟期燕麦为原料，设置对照、添加甲酸和添加布氏乳杆菌3个处理，青贮90 d后，测定其营养成分、发酵指标和细菌群落组成。结果表明：布氏乳杆菌和甲酸处理均改变不同物候期燕麦青贮饲料中细菌群落组成（P<0.05），并提高其乳酸细菌相对丰富度；与对照相比，用布氏乳杆菌和甲酸处理不同物候期的燕麦青贮后，蜡熟期的燕麦pH值降低（P<0.05），乙酸均增加9.7%，丙酸分别降低11.6%和8.6%，氨态氮分别降低11.3%和19.2%。综合细菌群落组成、发酵品质和营养成分来看，蜡熟期的燕麦添加布氏乳杆菌和甲酸后，其青贮品质较佳。     

半干旱区农田杂草的生活史对策研究

2008-2009年通过利用当地常见的10种杂草种植于不同处理的农田,研究半干早区农田杂草群落结构以及10种杂草群落组分种对环境因子的响应,结果表明,1)同一物种在不同的气候环境下,可以表现出不同的生活史策略.蝇虫实、田旋花和金荞麦2008年生活史策略分别具有竟争型(C)对策属性、胁迫忍耐型(S)对策属性和中间型(C-...     

Contrasting development of soil microbial community structure under no-tilled perennial and tilled cropping during early pedogenesis of a Mollisol

A range of agricultural practices influence soil microbial communities, such as tillage and organic C inputs, however such effects are largely unknown at the initial stage of soil formation. Using an eight-year field experiment established on exposed parent material (PM) of a Mollisol, our objectives were to: (1) to determine the effects of field management and soil depth on soil microbial community structure; (2) to elucidate shifts in microbial community structure in relation to PM, compared to an arable Mollisol (MO) without organic amendment; and (3) to identify the controlling factors of such changes in microbial community structure. The treatments included two no-tilled soils supporting perennial crops, and four tilled soils under the same cropping system, with or without chemical fertilization and crop residue amendment. Principal component (PC) analysis of phospholipid fatty acid (PLFA) profiles demonstrated that microbial community structures were affected by tillage and/or organic and inorganic inputs via PC1 and by land use and/or soil depth via PC2. All the field treatments were separated by PM into two groups via PC1, the tilled and the no-tilled soils, with the tilled soils more developed towards MO. The tilled soils were separated with respect to MO via PC1 associated with the differences in mineral fertilization and the quality of organic amendments, with the soils without organic amendment being more similar to MO. The separations via PC1 were principally driven by bacteria and associated with soil pH and soil C, N and P. The separations via PC2 were driven by fungi, actinomycetes and Gram (−) bacteria, and associated with soil bulk density. The separations via both PC1 and PC2 were associated with soil aggregate stability and exchangeable K, indicating the effects of weathering and soil aggregation. The results suggest that in spite of the importance of mineral fertilization and organic amendments, tillage and land-use type play a significant role in determining the nature of the development of associated soil microbial community structures at the initial stages of soil formation.