Growth,Biomass Production,and Nutrient Composition of Eucalyptus Seedlings Irrigated with Municipal Effluent in Loamy Sand Soil of Indian Desert

Abstract

An experiment comprised of five treatments [T₁ = municipal effluent @ 1 PET (without plant), T₂ = municipal effluent @ (1/2) PET, T₃ = municipal effluent @ 1PET, T₄ = municipal effluent @ 2 PET, and T₅ = good (canal) water @ 1 PET] was carried out with Eucalyptus camaldulensis. The aim was to utilize sewage water in growing tree plantation and to increase the supply of fuel wood to the growing urban population. Height, collar diameter, and number of branches were monitored periodically. Biomass and leaf and root growth were recorded at 24 months of age. Mineral composition and uptake were monitored to observe their removal from the soil. Increase in rate of municipal effluent application was associated with better tree growth compared to irrigation with canal water. At 24 month age, the T₄ was the best treatment in which E. camaldulensis attained 393 cm height and 6.6 cm collar diameter. Height and collar diameter of T₂ seedlings did not differ (P > 0.05) with respective parameters in T₅ treatment. Collar diameter increased by 1.2 times in T₃ treatment. Number of leaves and biomass increased with increase in quantity of municipal effluent. Modeling of total biomass against quantity of municipal effluent application produced better result with non‐linear fitting than the linear one. Mineral composition and accumulation in different parts of the seedling was high and varied with the quantity and nutrient composition of irrigation water. Concentration of total nitrogen (N), phosphorus (P), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) was high in the municipal effluent irrigated seedlings compared to the good water irrigated seedlings. However, sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg) were high in the seedlings of T₅ compared to T₂ and T₃ treatments. Municipal effluent did not show any toxicity to the seedlings up to 24 months age. Conclusively, the municipal effluents could be recommended as a good source of water and nutrient for tree biomass production to fulfill the requirement of fuel need in the suburban area.     

Comparing street tree assemblages and associated stormwater benefits among communities in metropolitan Cincinnati,Ohio, USA

Green infrastructure approaches leverage vegetation and soil to improve environmental quality. Municipal street trees are crucial components of urban green infrastructure because they provide stormwater interception benefits and other ecosystem services. Thus, it is important to understand the patterns and drivers of structural heterogeneity in urban street tree assemblages. In this study, we compared the forest structure of street trees across nine communities along both geographic and demographic gradients in metropolitan Cincinnati, Ohio, USA. Specifically, we used a two-part statistical model to compare both the proportion of sampled street segments containing zero trees, and basal area magnitude for street segments with trees. We made community-scale comparisons based on street tree management, socioeconomics, and geographic setting. Then, using modeled stormwater interception estimates from i-Tree Streets, we investigated the implications of heterogeneity in street tree assemblages for stormwater interception benefits. The forest structure of street trees varied across communities in relation to management practices, namely participation in the Tree City USA program. As a consequence of this structural difference, we observed a stark discrepancy in estimated stormwater interception between Tree City USA participants (128.7 m³/km street length) and non-participants (59.2 m³/km street length). While street tree assemblages did not vary by community poverty status, we did find differences according to community racial composition. In contrast to previous research, basal area was greater in predominantly black (i.e., African American) and racially mixed communities than in predominantly white communities. We did not observe structural differences across geographic strata. This research underscores the importance of proactive management practices for increasing the forest structure of street trees. Our findings regarding socioeconomics and geographic setting contrast previous studies, suggesting the need for continued research into the drivers of structural heterogeneity in street tree assemblages.     

地市级农科院所办公自动化管理平台实现探讨

本文以地市级农科院为例,围绕计算机外网与网站、内网及其维护等问题,探讨中小型企业办公自动化平台的实施。     

浅谈排水系统体制的合理选择

本文根据排水系统体制一般分为合流制和分流制两种类型,依据所处水质情况,合理选择排 水系统体制。     

城市污泥热解液体产物研究

利用外热式固定床反应器,在400～700℃温度范围内对城市污泥进行热解试验。结果表明,随热解温度的增加,热解液的产率逐渐升高,在550℃时达到最大值,但热解温度继续升高,热解液产率却不断减小;利用GC/MS联用仪对550℃时的热解油进行成分分析,其主要组分为杂环化合物(呋喃、吡啶等)的衍生物、酮类衍生物、苯酚衍生物、苯衍生物、长链脂肪烃衍生物和甾族化合物,其中胆甾烷和甲苯含量较高,分别达15.9%和11%。总之,利用热解法处理城市污泥是可行的,其热解油通过综合分析和分离提纯,可以作为潜在化工原料,具有较高的利用价值。     

基于岭南州府园林视角的古代惠州西湖延续性特征研究

惠州西湖作为岭南州府园林的典型个例,在跨越千年的演进过程中逐渐沉淀出与时间的显性关系,是历时演进的州府风景。基于岭南州府园林视角,运用历史研究法,引入“层积”概念,以古代惠州西湖为研究对象,归纳其延续性特征的基础为历代州府接续建管与“发现—建设—游赏—传颂”风景营建迭代循环;总结其延续性特征的结果为单要素演变和各要素整体状态叠合的空间层积与跨越时空情景“逝反”的文化层积。     

Assessment of groundwater quality and its variations in the capture zone of a pumping well in an agricultural area

Agricultural activities are frequently associated with water contamination. The spreading and storage of fertilizers, for instance, may result in groundwater contamination due to pollutants leaching into an aquifer. Nitrates and fecal bacteria are two important contaminants associated with agriculture. Thus, the development of efficient strategies for groundwater protection in agricultural areas requires an assessment of these two contaminants. Given this perspective, groundwater quality monitoring was carried out over the whole capture zone of a municipal well located in an agricultural area in the St.-Lawrence Lowlands in Québec. Thirty-eight piezometers were installed within the roughly 2 km² capture area of the well to measure physico-chemical parameters such as major ions, field measured parameters (pH, electrical conductivity, dissolved oxygen, water level, temperature), and isotopic ratios, bacteriological parameters (Heterotrophic Plate Count—HPC, enterococci, total coliforms, Escherichia coli) and their variations in space and time. Groundwater was sampled from the pumping well and the piezometers during 25 field campaigns in 2005, 2006 and 2007. The results demonstrate the impact of agricultural activities on nitrate contamination. They indicate high spatial and temporal variations in nitrate concentrations, from 6 to 125 mgNO₃⁻/L within the capture area, with 40% of the samples exceeding the Québec drinking water limit of 45 mgNO₃⁻/L. Nitrate pollution in the municipal well exceeded 45 mgNO₃⁻/L during 2005, but no bacteriological contamination was observed. The results also show a high variability of nitrate concentration with depth within the capture zone. Electrical conductivity appears as a good indicator of the presence of nitrate and calcium ions in this capture zone. Correlations between nitrate, calcium and chloride suggest that these ions come from the same source of fertilizer. Nitrate isotopic composition suggests that nitrate in groundwater originates from both chemical and organic fertilizers. The bacteriological results show that the extracted volume of water during sampling of a piezometer has a significant impact on the bacteria count. The variability of bacteriological pollution is important in space and time, showing a higher contamination during summer. Only 2% of the raw water samples exhibit contamination exceeding the drinking water standard for treated water. Total coliforms seem to be a good precursor of E. coli or enterococci contamination. Globally, the physico-chemical and bacteriological groundwater quality within the studied capture area and the pumping well shows contamination by nitrates, but low contamination levels by fecal bacteria.     

城市垃圾资源化利用探讨

在调查分析浙江省丽水市垃圾资源化现状和资源化潜力的基础上,着重探讨了生活垃圾和建筑垃圾资源化管理和处理措施,并展望了我国城市垃圾处理的前景.     

生活垃圾和污泥对土壤肥力及油菜生长的影响

通过盆栽试验研究了不同用量垃圾和污泥对土壤养分和油菜生长的影响。结果表明:施用3%、5%、8%的污泥和6%、8%、10%的垃圾,土壤有机质和速效N、P、K都显著高于对照,且随着用量的增大,效果增加。施用垃圾和污泥处理的油菜显著地比对照、施化肥处理生长旺盛,叶片大而绿,产量增加。测定各处理土壤中的重金属含量,其中Cr含量差异不显著,Pb、Cu差异显著,虽然施用不同用量垃圾和污泥不同程度地增加了土壤中重金属的含量,但都没有超出污染标准。因此,合理利用垃圾和污泥能提高土壤肥力,增加作物产量。