Changes in Soil Particulate Organic Matter, Microbial Biomass, and Activity Following Afforestation of Marginal Agricultural Lands in a Semi-Arid Area of Northeast China

Afforestation of agricultural lands has been one of the major land use changes in China in recent decades. To better understand the effect of such land use change on soil quality, we investigated selected soil physical, chemical and microbial properties (0–15 cm depth) in marginal agricultural land and a chronosequence of poplar (Populus euramericana cv. ‘N3016’) plantations (5-, 10-, 15- and 20-years old) in a semi-arid area of Northeast China. Soil bulk density significantly declined after conversion of agricultural lands to poplar plantations. Soil total organic carbon (TOC) and nitrogen (TN) concentrations, microbial biomass C (MBC) and potential N mineralization rate (PNM) decreased initially following afforestation of agricultural lands, and then increased with stand development. However, soil metabolic quotient (qCO₂) exhibited a reverse trend. In addition, soil particulate organic matter C (POM-C) and N (POM-N) concentrations showed no significant changes in the first 10 years following afforestation, and then increased with stand age. These findings demonstrated that soil quality declined initially following afforestation of agricultural lands in semi-arid regions, and then recovered with stand development. Following 15 years of afforestation, many soil quality parameters recovered to the values found in agricultural land. We propose that change in soil quality with stand age should be considered in determining optimum rotation length of plantations and best management practices for afforestation programs.     

Fish Community Structure as a Measure of Degradation and Rehabilitation of Riparian Systems in an Agricultural Drainage Basin

/ Assessing the health of ecological components of agroecosystems may be accomplished by examining changes in the drainage basin, which serves as an integrator of the agroecosystem landscape. In this study we examined fish communities in terms of an array of indicators of structure and related these to changes in riparian vegetation and agricultural practice. Evidence suggests management practices designed to foster healthier environments by, for example, reestablishing riparian vegetation were associated with positive impacts on the integrity of the fish community. At the same time, continued intensification of agricultural practices in parts of the drainage basin in recent years likely has had an off-setting influence in overall improvements in agroecosystem health. Assessments of changes in the structure of the fish associations provide the balance sheet by which the counteracting influences can be aggregated and assessed.KEY WORDS: Fish community structure; Riparian system; Agricultural drainage basin     

Using the Language of NIMBY: a topic for research, not an activity for researchers

During the 1990s the social scientific literature on local opposition to proposed developments has moved from a focus on individual motives to a concern with the social causes and significance of such protest. However, the language of NIMBYism is still widely used by researchers. Drawing on data from a case study of local responses to a proposed new road the central role that the language of NIMBY plays within siting disputes is illustrated, and it is concluded that academics interested in understanding the dynamics and process of local development disputes might usefully study participants' use of NIMBY, but should distance themselves from the activity of attributing NIMBYism to certain parties. In addition those concerned with managing, mediating or resolving local disputes should also steer clear of the language of NIMBY and engage with the diversity and complexity of local concerns and interests.     

污水处理厂化学除磷精确控制系统研究——以山东某污水处理厂为例

我国总磷排放标准日趋严格,污水处理厂为保证出水总磷达标,过量投加化学除磷剂,造成资源浪费.为在出水水质达标的基础上节省化学除磷剂添加量,以山东某污水处理厂为例设计了化学除磷精确控制系统.在充分考虑仪器故障潜在风险的前提下,根据进水磷酸盐负荷实时调整药剂投加量,采用"前馈+反馈"控制的模式,实现加药过程的自动化及智能化....     

Treatment of domestic wastewater using an anaerobic baffled reactor followed by a duckweed pond for agricultural purposes

The treatment and reuse of domestic wastewater using an anaerobic baffled reactor (ABR) followed by a duckweed pond (DWP) were the main theme of the present study. The ABR was fed continuously with domestic wastewater at four HRTs ranging from 8 to 24 h and corresponds to organic loading rates ranging from 0.67 to 2.1 kg COD/m³/day. The ABR effluent was fed to a DWP operating at 10 and 15 days. The performance of the ABR at the four HRTs gave satisfactory results. Chemical oxygen demand (COD) removal was between 68 and 82%. Fecal coliform removal was between 1 to 2 logs. The 12- and 18-h hydraulic retention times (HRTs) gave close results, as indication of the possible selection of the 12-h HRT as the optimum operation for the ABR based on economic advantage. The ABR compartmentalized structure gave results higher than those produced by the one-stage digester and similar to those produced by the two-phase anaerobic digestion process. Duckweed ponds as post-treatment operated at 10 days and 15 days gave the best results at 15-day HRT, where it was possible to remove 73.4% of nitrogen and 65% of phosphorus and produce protein-rich dry duckweed of 105 kg/ha/day on average. The removal of fecal coliform (FC) in duckweed ponds was 3–4 logs. The final treated domestic sewage characteristics proved its compliance with the Egyptian standards for reuse in restricted irrigation.     

Selection of a water-extractable phosphorus test for manures and biosolids as an indicator of runoff loss potential

The correlation of runoff phosphorus (P) with water-extractable phosphorus (WEP) in land-applied manures and biosolids has spurred wide use of WEP as a water quality indicator. Land managers, planners, and researchers need a common WEP protocol to consistently use WEP in nutrient management. Our objectives were to (i) identify a common WEP protocol with sufficient accuracy and precision to be adopted by commercial testing laboratories and (ii) confirm that the common protocol is a reliable index of runoff P. Ten laboratories across North America evaluated alternative protocols with an array of manure and biosolids samples. A single laboratory analyzed all samples and conducted a separate runoff study with the manures and biosolids. Extraction ratio (solution:solids) was the most important factor affecting WEP, with WEP increasing from 10:1 to 100:1 and increasing from 100:1 to 200:1. When WEP was measured by a single laboratory, correlations with runoff P from packed soil boxes amended with manure and biosolids ranged from 0.79 to 0.92 across all protocol combinations (extraction ratio, filtration method, and P determination method). Correlations with P in runoff were slightly lower but significant when WEP was measured by the 10 labs (r=0.56-0.86). Based on laboratory repeatability and water quality evaluation criteria, we recommend the following common protocol: 100:1 extraction ratio; 1-h shaking and centrifuge 10 min at 1500xg (filter with Whatman #1 paper if necessary); and determining P by inductively coupled plasma-atomic emission spectrometry or colorimetric methods.     

Using a geographical information system for monitoring space shuttle launches: Determining cumulative distribution of deposition and an empirical test of a spatial model

Space shuttle launches produce localized hydrochloric acid deposition. The interaction of solid rocket motor exhaust and deluge water released on the pad at the time of launch results in the formation of an exhaust cloud. The spatial pattern and extent of deposition from the launch cloud are predicted by the rocket exhaust effluent diffusion (REED) model. The actual pattern of deposition has been mapped by field surveys for each shuttle launch since 1981. In this paper we use a geographical information system (GIS) to compare model predictions with ground patterns for 49 shuttle launches. We also compile cumulative maps of deposition patterns needed to consider long-term impacts. The direction of launch cloud movement did not differ significantly from model predictions. The REED model overpredicted both the area that received deposition and the maximum distance from the launch pad that deposition occurred. Severe vegetation damage was restricted to near-field deposition areas within 1980 m north of each launch pad. Total area impacted from launches has been 87.0 ha around pad 39A and 52.9 ha around pad 39B. Far-field deposition has caused leaf spotting from acid droplets or aluminum oxide over a wider and more variable area than near-field. A total of 19,397 ha has received deposition, but 63.6% of this area has received deposition only one time and 92.2% not more than three times. GIS techniques provide means to test spatial models and compile information useful for assessing cumulative impacts.     

Making the Best of a Pest: The Potential for Using Invasive Zebra Mussel (Dreissena Polymorpha) Biomass as a Supplement to Commercial Chicken Feed

Invasive non-native species frequently occur in very high densities. When such invaders present an economic or ecological nuisance, this biomass is typically removed and landfill is the most common destination, which is undesirable from both an economic and ecological perspective. The zebra mussel, Dreissena polymorpha, has invaded large parts of Europe and North America, and is routinely removed from raw water systems where it creates a biofouling nuisance. We investigated the suitability of dried, whole zebra mussels as a supplement to poultry feed, thus providing a more attractive end-use than disposal to landfill. Measurable outcomes were nutrient and energy composition analyses of the feeds and production parameters of the birds over a 14 day period. Zebra mussels were a palatable feed supplement for chickens. The mussel meal contained high levels of calcium (344.9 g kg^?1), essential for egg shell formation, which was absorbed and retained easily by the birds. Compared with standard feed, a mussel-supplemented diet caused no significant effects on production parameters such as egg weight and feed conversion ratio during the study period. However, protein and energy levels in the zebra mussel feed were much lower than expected from the literature. In order for zebra mussels to be a viable long-term feed supplement for poultry, flesh would need to be separated from the shells in an economically viable way. If zebra mussels were to be used with the shells remaining, it seems that the resultant mussel meal would be more suitable as a calcium supplement.     

EDI技术在铝箔电子材料制造行业含酸废水中的应用——以新疆某铝箔电子材料制造企业为例

本文根据铝箔电子材料制造行业的废水特点,以新疆某铝箔电子材料制造企业为例,在对比不同废水处理技术背景下,重点介绍EDI技术在含酸废水处理中的应用,即主要考虑去除铝离子、预脱盐、EDI精除盐的工艺,最终实现资源循环利用,达到节能减排的目的。     

Application of a Three-Dimensional Water Quality Model as a Decision Support Tool for the Management of Land-Use Changes in the Catchment of an Oligotrophic Lake

While expansion of agricultural land area and intensification of agricultural practices through irrigation and fertilizer use can bring many benefits to communities, intensifying land use also causes more contaminants, such as nutrients and pesticides, to enter rivers, lakes, and groundwater. For lakes such as Benmore in the Waitaki catchment, South Island, New Zealand, an area which is currently undergoing agricultural intensification, this could potentially lead to marked degradation of water clarity as well as effects on ecological, recreational, commercial, and tourism values. We undertook a modeling study to demonstrate science-based options for consideration of agricultural intensification in the catchment of Lake Benmore. Based on model simulations of a range of potential future nutrient loadings, it is clear that different areas within Lake Benmore may respond differently to increased nutrient loadings. A western arm (Ahuriri) could be most severely affected by land-use changes and associated increases in nutrient loadings. Lake-wide annual averages of an eutrophication indicator, the trophic level index (TLI) were derived from simulated chlorophyll a, total nitrogen, and total phosphorus concentrations. Results suggest that the lake will shift from oligotrophic (TLI = 2–3) to eutrophic (TLI = 4–5) as external loadings are increased eightfold over current baseline loads, corresponding to the potential land-use intensification in the catchment. This study provides a basis for use of model results in a decision-making process by outlining the environmental consequences of a series of land-use management options, and quantifying nutrient load limits needed to achieve defined trophic state objectives.     

Geostatistical spatiotemporal analysis of air temperature as an aid to delineating thermal stability zones in a potential show cave: implications for environmental management

Air temperature in several galleries of the Covadura System (Sorbas Gypsum Karst, Almería) was measured at monthly intervals over a period of 1 year. The spatial temperature distribution for each month was modeled in a geostatistical framework. The mean trend of the air temperature and the difference between each experimental temperature measurement and this trend were calculated over space and time. Both the trend and residual component were characterized using a geostatistical space-time model. A large spatial trend of the air temperature was found due to the orientation of galleries within the cave system and as a function of the distance from the main cave entrance. Kriging was used for the spatial estimation of the time covariance of the residuals. This enabled the delimitation of the cave into three zones of varying environmental risk in the event of being opened to visits by the public, according to the degree of stability of air temperature over space and time. The influence of human presence on the spatial temperature distribution was assessed using data collected during a year (2000/2001) in pilot galleries opened to the public. An average visit corresponding to August was selected comprising 16 people over a period of 53 min. This average visit influenced the spatial temperature pattern at distances of more than 90 m from the cave entrance, according to the geostatistical model adopted. Within this zone the mean thermal increment generated by human presence was estimated to be 0.26 degrees C. The spatiotemporal mathematical model of the cave air temperature has been revealed as a useful tool for the environmental management of show caves.