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.     

立地条件和林分结构对有林地生产力的影响

通过分析有林地生产力与立地条件和林分结构中各因子的关系,探索制约有林地生产力的主要因素.结果表明:不同立地质量中Ⅰ类地单位蓄积量最高(268.86±20.24 m3/hm2),不同坡向中东坡单位蓄积量最高(269.78±38.54 m3/hm2),不同树种组成中10杉类型单位蓄积量最高(259.33±14.62 m3/hm2);有林地生产力与林分年龄、林分密度正相关,相关系数R分别为0.590、0.460;有林地生产力与海拔、坡度相关性不显著.以上结果说明立地质量、坡向和树种组成对有林地生产力影响显著;有林地生产力与林分年龄、林分密度相关,与海拔、坡度无关.     

光辐射染色木材的变色规律及化学组分结构的变化

以I-214杨木染色单板为试材、氙光作为辐射光源,考察其在100h光照过程中表面颜色的变化规律;依据红外光谱图的谱峰位置和谱峰相对吸收强度,分析和确定光变色过程中染色杨木木材的化学组分。结果表明:染色杨木木材受光辐射易发生变色,其中酸性蓝染色单板的明度指数L*和色品指数b*变化显著,其光变色度显著大于酸性大红GR染色单板;若以波数1510cm-1为基准,非共轭羰基C=O振动的吸收峰(1738cm-1)吸收强度显著增强;共轭羰基C=O伸缩振动的吸收峰(1650cm-1)吸收强度有所增强;芳香环骨架C-C振动的吸收峰(1510cm-1)吸收强度明显减弱;C-O-H振动的吸收峰(1160～1052cm-1)吸收强度有所减弱。     

轻钢结构抗震节能体系在“塞上农民新居”中的应用

针对宁夏地区农民传统住宅抗震性差，建筑外围护结构保温性能差，采暖系统能源消耗量大，环境污染严重等问题，提出采用轻钢结构配以轻质保温板材的轻钢结构抗震节能体系，以期为宁夏农村住宅设计提供指导性建议。     

Impact of soil engineering by two contrasting species of earthworms on their dispersal rates

By burrowing galleries and producing casts, earthworms are constantly changing the structure and properties of the soils in which they are living. These changes modify the costs and benefits for earthworms to stay in the environment they modify. In this paper, we measured experimentally how dispersal behaviour of endogeic and anecic earthworms responds to the cumulative changes they made in soil characteristics. The influence of earthworm activities on dispersal was studied in standardised mesocosms by comparing the influence of soils modified or not modified by earthworm activities on earthworm dispersal rates.The cumulative use of the soil by the earthworms strongly modified soil physical properties. The height of the soil decreased over time and the amount of aggregates smaller than 2 mm decreased in contrast to aggregates larger than 5 mm that increased. We found that: (i) earthworm activities significantly modified soil physical properties (such as bulk density, soil strength and soil aggregation) and decreased significantly the dispersal rates of the endogeic species, whatever the species that modified the soil; (ii) the decreasing in the dispersal proportion of the endogeic species suggests that the cost of engineering activities may be higher than the one of dispersal; (iii) the dispersal of the anecic species appeared to be not influenced by its own activities (intra-specific influences) or by the activities of the endogeic species (inter-specific influences). Overall these results suggest that the endogeic species is involved in a process of niche construction, which evolved jointly with its dispersal strategy.     

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-...     

肾上腺皮质肿瘤良恶性鉴别方法探究

肾上腺皮质肿瘤（Adrenocortical Tumor,ACT）是一种常见的肿瘤,存在于人体的内分泌系统中,并且是引发肾上腺皮质癌（Adrcnocortical Carcinoma,ACC）进而导致死亡的主要原因.经典的＂Weiss系统＂在诊断明确性上存在种种无法解决的问题,但随着科技水平的发展,人们开始探索新的途径来鉴别ACT的良恶性,于是开始有了影像学和分子生物学技术等特异性的检查方法,从而进一步增强了诊断的明确性.现通过对比的方式,探究肾上腺皮质肿瘤（Adrenocortical Tumor,ACT）影像学检查和分子生物学技术检查的结果,从而能更准确地鉴别其良恶性.