在重金属污染环境下散栖欧Ping的肾中毒效应

散栖欧Ｐinｇ的试验标本取自瑞典一硫化矿冶炼厂的污染区及对照区。试验山鼠放大代谢笼内，２４小时收集其尿液。对其血浆及整个肾脏分别进行了血浆肌酸酐和金属含量分析。对尿液体积，总蛋白质、肌酸酐和金属含量进行了分析。取纂我的山鼠，其肾的镉 一增加了３０－４０倍，出现多尿症和蛋白尿症。与匐元素不同，肾的其它金属含量在取自两个实验区的山鼠中是相似的，因为这些金属元素含量小球的功能有关。当整个肾的匐含量达到４ｍ     

Behavior of Two Phenyl Urea Herbicides in Clayey Soils and Effect of Alternating Dry-Wet Conditions on their Availability

Adsorption and mobility of linuron (3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea) and diuron (3-(3,4-dichlorophenyl)-1, 1-dimethylurea) were studied in clayey soils from the Gharb area (Morocco). Soils A and B were planted with sun flower (Helianthus annuus) while soil C was planted with sugar cane (Saccharum offcinarum). Adsorption was studied for linuron in soils A and B, while mobility was studied only in soil B. Adsorption data were found to fit the Freundlich equation with correlation coefficients r² > 0.9. Freundlich coefficients (K_f, n_f) were in agreement with L and S isotherm types for soils A and B, respectively. Values of K_oc (195 and 102) indicate moderate adsorption. Desorption isotherms for linuron showed hysteresis for both soils. The pesticide would be more bound to soil A (H = 8.44) than to soil B (H = 4.01). The effect of alternating wet and dry conditions was tested for soils A and B. Results showed that retention would increase in soil subject to an additional wet and dry cycle. In the case of diuron isotherm was of type L in soil C. Desorption was noticeable at high concentrations and tended to decrease when concentrations diminished. Mobility of linuron was tested in polyvinyle chloride (PVC) columns, which received different treatments before their percolation. The pesticide was more mobile in a previously saturated column. In columns subject to a drying step after saturation with water, linuron mobility was greatly reduced.     

氮肥:迎接当代挑战

商业氮肥以8170万t之巨,约占现今所有抵达地球耕地氮肥的50%,至少给40%的人口提供了基本的食物需求.摆在我们面前的挑战是,继续帮助满足那种需求,而又要通过改善氮肥利用效率把对环境的负面影响减到最小.在美国,玉米上的氮肥效率在近20年里提高了30%以上,但在玉米和其它作物上尚有潜力可挖.在大多数亚洲国家目前的氮肥效率和生产率比北美一般要低,但他们正在做出努力加以改进.化肥工业认识到在满足人类现今和将来的基本需求方面它所担负的关键角色.它已准备好迎接新的挑战,采用新的实践和技术来提高效率,并以此不仅支持人类生命而且改善人们生活的质量.     

Review of greenhouse gas emissions from crop production systems and fertilizer management effects

Fertilizer nitrogen (N) use is expanding globally to satisfy food, fiber, and fuel demands of a growing world population. Fertilizer consumers are being asked to improve N use efficiency through better management in their fields, to protect water resources and to minimize greenhouse gas (GHG) emissions, while sustaining soil resources and providing a healthy economy. A review of the available science on the effects of N source, rate, timing, and placement, in combination with other cropping and tillage practices, on GHG emissions was conducted. Implementation of intensive crop management practices, using principles of ecological intensification to enhance efficient and effective nutrient uptake while achieving high yields, was identified as a principal way to achieve reductions in GHG emissions while meeting production demands. Many studies identified through the review involved measurements of GHG emissions over several weeks to a few months, which greatly limit the ability to accurately determine system-level management effects on net global warming potential. The current science indicates: (1) appropriate fertilizer N use helps increase biomass production necessary to help restore and maintain soil organic carbon (SOC) levels; (2) best management practices (BMPs) for fertilizer N play a large role in minimizing residual soil nitrate, which helps lower the risk of increased nitrous oxide (N₂O) emissions; (3) tillage practices that reduce soil disturbance and maintain crop residue on the soil surface can increase SOC levels, but usually only if crop productivity is maintained or increased; (4) differences among fertilizer N sources in N₂O emissions depend on site- and weather-specific conditions; and (5) intensive crop management systems do not necessarily increase GHG emissions per unit of crop or food production; they can help spare natural areas from conversion to cropland and allow conversion of selected lands to forests for GHG mitigation, while supplying the world's need for food, fiber, and biofuel. Transfer of the information to fertilizer dealers, crop advisers, farmers, and agricultural and environmental authorities should lead to increased implementation of fertilizer BMPs, and help to reduce confusion over the role of fertilizer N on cropping system emissions of GHGs. Gaps in scientific understanding were identified and will require the collaborative attention of agronomists, soil scientists, ecologists, and environmental authorities in serving the immediate and long-term interests of the human population.     

Cost‐Effectiveness of Using Small Vertebrates as Indicators of Disturbance

In species‐rich tropical forests, effective biodiversity management demands measures of progress, yet budgetary limitations typically constrain capacity of decision makers to assess response of biological communities to habitat change. One approach is to identify ecological‐disturbance indicator species (EDIS) whose monitoring is also monetarily cost‐effective. These species can be identified by determining individual species’ responses to disturbance across a gradient; however, such responses may be confounded by factors other than disturbance. For example, in mountain environments the effects of anthropogenic habitat alteration are commonly confounded by elevation. EDIS have been identified with the indicator value (IndVal) metric, but there are weaknesses in the application of this approach in complex montane systems. We surveyed birds, small mammals, bats, and leaf‐litter lizards in differentially disturbed cloud forest of the Ecuadorian Andes. We then incorporated elevation in generalized linear (mixed) models (GL(M)M) to screen for EDIS in the data set. Finally, we used rarefaction of species accumulation data to compare relative monetary costs of identifying and monitoring EDIS at equal sampling effort, based on species richness. Our GL(M)M generated greater numbers of EDIS but fewer characteristic species relative to IndVal. In absolute terms birds were the most cost‐effective of the 4 taxa surveyed. We found one low‐cost bird EDIS. In terms of the number of indicators generated as a proportion of species richness, EDIS of small mammals were the most cost‐effective. Our approach has the potential to be a useful tool for facilitating more sustainable management of Andean forest systems. Rentabilidad del Uso de Pequeños Vertebrados como Indicadores de Perturbaciones     

Nitrogen fertilizers: meeting contemporary challenges

At 81.7 million tonnes (Mt), commercial fertilizer nitrogen (N) accounts for approximately half of all N reaching global croplands today and supplies basic food needs for at least 40% of the population. The challenge is to continue to help meet that need while minimizing the risk of negative environmental impacts through improved N-use efficiency. Fertilizer-N efficiency on corn in the US has increased more than 30% over the last 20 years, but additional progress can be made for corn and other crops. Current N efficiency and productivity are generally lower in most of Asia than in North America, but they are improving. The fertilizer industry recognizes its crucial role in meeting basic human needs, now and in the future. It stands ready to meet the challenge of adopting new practices and technologies that will allow it to do so with greater efficiency and in a way that not only sustains life, but also sustains the quality of life.