"国六条"后众生相--我们离绿色地产还有多远

现象：一位王姓地产商称，2002年，他在某区金开大道拿下200多亩地，当时出让价为40多万元／亩，由于缺乏启动资金，至今未开发。按新政策要求，这些土地将被无偿收回。     

Sown species richness and realized diversity can influence functioning of plant communities differently

Biodiversity–ecosystem functioning experiments (BEF) typically manipulate sown species richness and composition of experimental communities to study ecosystem functioning as a response to changes in diversity. If sown species richness is taken as a measure of diversity and aboveground biomass production as a measure of community functioning, then this relationship is usually found to be positive. The sown species richness can be considered the equivalent of a local species pool in natural communities. However, in addition to species richness, realized diversity is also an important community diversity component. Realized diversity is affected by environmental filtering and biotic interactions operating within a community. As both sown species richness and the realized diversity in BEF studies (as well as local species pool vs observed realized richness in natural communities) can differ markedly, so can their effects on the community functioning. We tested this assumption using two data sets: data from a short-term pot experiment and data from the long-term Jena biodiversity plot experiment. We considered three possible predictors of community functioning (aboveground biomass production): sown species richness, realized diversity (defined as inverse of Simpson dominance index), and survivor species richness. Sown species richness affected biomass production positively in all cases. Realized diversity as well as survivor species richness had positive effects on biomass in approximately half of cases. When realized diversity or survivor species richness was tested together with sown species richness, their partial effects were none or negative. Our results suggest that we can expect positive diversity–productivity relationship when the local species pool size is the decisive factor determining realized observed diversity; in other cases, the shape of the diversity–functioning relationship may be quite opposite.     

Effects of vegetable oil residue after soil extraction on physical-chemical properties of sandy soil and plant growth

Vegetable oil has the ability to extract polycyclic aromatic hydrocarbons(PAHs)from contaminated sandy soil for a remediation purpose,with some of the oil remaining in the soil.Although most of the PAHs were removed,the risk of residue oil in the soil was not known.The objective of this study was to evaluate the effects of the vegetable oil residue on higher plant growth and sandy soil properties after soil extraction for a better understanding of the soil remediation.Addition of sunflower oil and column ex...     

基于THQ的锌冶炼厂周围人群食用蔬菜的健康风险分析

采用对应采样方法研究葫芦岛锌冶炼厂周围地区土壤、蔬菜中Pb、Cd、Hg、Zn、Cu的含量,采用目标危险系数(THQ)的方法对锌厂周围人群食用蔬菜的健康风险进行了评价.结果表明,锌厂周围蔬菜已经受到了重金属的严重污染,仅通过消耗蔬菜,锌厂周围成人居民Pb、Cd、Hg、Zn、Cu的平均摄入量分别为574.3、301.4、1.322、5263、292.5 μg·d-1;儿童Pb、Cd、Hg、Zn、Cu的平均摄入量为446.8、234.5、1.029、4095、227.6 μg·d-1.目标危险系数(THQ)评价表明,葫芦岛锌厂周围人群摄入Pb、Cd的目标危险系数大于1,存在Pb、Cd的健康风险;锌厂周围成人和儿童食用蔬菜而摄入重金属的TTHQ分别为5.79～9.90、7.6～13.0,蔬菜中重金属的复合污染已经使锌厂周围的居民面临潜在的健康风险.     

新河涌:像花一样盛开

每条河涌都有故事,都是一段活着的历史……     

Variations in land requirements for meat production

Production of meat requires substantial amounts of feed grains which in turn require vast amounts of land. Future population growth and increase in consumption will raise the demand for meat and with it the land required for meat production. This paper analyses the various factors that affect land requirements for meat production. Meat production by Dutch broilers, pigs and beef cattle on their current feeds are compared and options for change are evaluated with respect to their nutritional needs. Differences in land requirements of a factor of 3 were found between different agricultural production systems and feeds as well as between types of livestock. It is shown that broilers have the lowest land requirement while beef cattle have the highest. The variation in feed crop yields between agricultural systems is discussed. It is concluded that due to the large variation within the system there is potential for reduction in the land requirements for meat production.     

Air pollutant yield-loss assessment for four vegetable crops

Crop loss was evaluated for leaf lettuce, green onion, turnip and beet in a field chamber system using a gradient of ambient pollutants. The nine-chamber gradient had air flows adjusted to filter pollutants to 100, 90, 80, 70, 60, 50, 35, 20 and 0% of ambient or ambient plus added ozone. Dose-response functions were calculated for the four crops using both a 12-h seasonal mean dose statistic and a 0.10 μl l⁻¹ threshold dose summary. Yield-loss functions were generated from yield equations. Crop yield-loss functions for green onion, turnips and beets were significant with 12-h seasonal mean ozone dose. Yield-loss functions based on the 0.10 μl l⁻¹ threshold were significant for onion, lettuce and beets. Multiple regression analysis using both dose summary statistics did not produce a better predictive model of yield loss for any of the four crops examined.