Advanced Materials Research Vols. 955-959

Abstract: the paper discussed the pollution of heavy metal in vegetable farm soils in Fuxin city, China. The levels of lead, cadmium, chromium, arsenic and mercury in 5 soil samples obtained from vegetable farm soil were detected. The levels of lead, cadmium, chromium, arsenic and mercury were17.12-34.62mg/kg,0.12-0.24 mg/kg,32.28-50.96 mg/kg,6.86-8.83 mg/kg and 0.14-0.16 mg/kg, respectively. At same time, we have done some evaluation for vegetable farm soils pollution of Fuxin. The vegetable farm soils were contaminated by mercury in great universality, and the next is cadmium. As for contaminated degree, mercury-pollution is severe, and the second were cadmium, and the rest are slightly polluted. Compared the present pollution change, soil pollution in Fuxin is aggravate, which should grasp management, especially the serious mercury pollution that should pay attention to the monitoring mercury enterprises.

Abstract: In order to profile the research status of soil pollution, and grasp the development direction of the disciplines, based on the soil pollution related research papers included in EI compendex, by the controlled terms of EI thesaurus, we used words co-occurrence clustering to identify the current six subfields of international soil pollution studies, investigated the development and change of them with time case, and pointed out the journals that different subfields should focus on by analyzing the relevant periodicals distribution, to provide reference for the research institutes, researchers, and policy makers in soil pollution related field.

Abstract: Field observations, theoretical analyses and laboratory experiments indicated that the capillary fringe plays an important role in maintaining the ecological environment of desert salt lake. Taking Ulan Buh Desert as an example, this paper simulated capillary water rise process by using an experimental device and proposed ecological significance based on observation of 107 phreatic water wells.The results show that the theoretical maximum height of capillary water rise may reach 2.39m; velocity of capillary water rise is fast at first, and then is slow, it finally tends towards steady; the amount of capillary water rise may reach 34.4cm per unit area. Moisture content in vadose zone is inversely proportional to the summation of depth of groundwater and height of capillary water rise, if the depth of groundwater is within 1-8m. Characters of Capillary water rise determine the water supplying condition, further control the distribution pattern of the desert vegetation species.

Abstract: Since 2013, fog-haze weather occurs frequently in China, which arouses great concern in society. Fog-haze has a close relationship with the accumulation of mass contaminants, adverse weather conditions and regional transport of contaminants. The uncertainty pollutants source and “contribution rate” covers a mystical veil for fog-haze weather. Persistent fog-haze weather will harm people's health, hinder the smooth running of the transport system, break the eco-system balance, and even undermine the credibility and good international image of the government. Haze control should be based on sound environmental law. Optimize the energy structure, strengthen the vehicle management as soon as possible, and make efforts to implement joint prevention and raise public participation. Under the country’s efforts, getting rid of fog-haze predicament is just around corner.

Abstract: A survey was conducted in Hangjiahu Plain Wetlands to study the baseline information, types, vegetation, characteristics, ecological values, construction and management. The results showed that: the total area of Hangjiahu plain wetlands coverage ​​181,800 hectares, involving 5 types. The natural resources were very rich in wetlands.There are 8 birds species under national protection and 4 wild plants under national protection. There are 10 wetland places under state protection by government. This is the Nature Protection Zone of Hangzhou Xixi National Wetland Park, a name on the List of international wetlands.Taihu Wetland Park is National wetland park. Proposals on protection and management of the wetland were made by considering practical.

Abstract: Understanding the leaf N, P concentrations and nutrient resorption of plants growing in phosphorus–enriched soil (PES) can provide new data for ecostoichiometric research and ecological model building. In this study, 117 green leaves and 53 senesced leaves of dominant plants in PES in the Dianchi Lake watershed, SW China, were sampled. Plants in PES had high fresh leaf P (4.60mg/g), senesced leaf P (2.70mg/g), and low fresh leaf N: P (4.41), senesced leaf N: P (3.21). P resorption efficiency (PRE) (25.09%) was significantly lower than N resorption efficiency (NRE) (52.68%). Forbs had the highest P content in fresh (5.35mg/g) and senesced leaf (3.25mg/g) among plants forms. Although NRE was varied among plant forms, the difference in PRE was not significant. In conclusion, PES has a tremendous impact on the patterns of leaf N, P and nutrient resorption of different plant forms, those results were different from general results.

Abstract: The natural radionuclide (²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K) concentrations in 152 soil samples were determined from two major granite areas in Guangzhou, using high resolution γ-ray spectroscopic system based on the characteristic spectral peaks. The mean activity values for ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were found to be 156.6±98.8, 160.9±96.5, 184.8±101.5 and 832.5±493.1 Bq kg^–1 dry mass, respectively. The absorbed dose rate (D) calculated from activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K ranged from 53.2 to 497.1 nGy h^–1 with a mean of 220.7 nGy h^–1. The Radium equivalent activity (Ra_eq), the outdoor annual effective dose and the external hazard index (I_r), which resulted from the natural radionuclides in soil, were also calculated and found to vary from 119.7 to 1117.2 Bq kg^–1, from 0.07 to 0.61 mSv and from 0.33 to 3.07, respectively. The radium equivalent activities and the external hazard index in all the soil samples were same as 64.5% higher than the limit of 370 Bq kg^–1 and 1.0, respectively. The outdoor annual effective dose was higher than the worldwide mean value of 0.07 mSv.

Abstract: In this study, we sought to analyze the pressures of the grassland ecosystem in China and explore practical countermeasures to protect grassland biodiversity. The prominent ecological problems in grassland biodiversity conservation included rapid population growth, economic development, resource exploitation and global climate change, among which human interferences strongly influenced the grassland ecosystem. Rapid population growth and economic development still severely restricted biodiversity conservation, but coal resource exploitation gradually developed a new serious pressure for grassland biodiversity. In addition, climate change further aggravated biodiversity loss. According to these pressures, we proposed several practical countermeasures such as readjusting the industrial structure, and relieving the pressures of grassland, and conducting near-natural restoration as well as carrying out ecological compensation. This study will provide the scientific reference for manager and policy-makers of grassland biodiversity conservation.

Abstract: The effect of heavy metal Hg on activities of soil urease, catalase and invertase in corn field with different nitrogen supplying levels.. The concentrations of Hg²⁺ were 0, 0.3125, 0.625, 1.25, 2.50 mg·kg^-1 dried soil, respectively. The three enzymes responded differently to Hg stress under different N treatments, the inhibition effect of Hg on urease activity was most significant, while the inhibition on catalase only existed at high nitrogen levels, the response of soil invertase under Hg stress firstly increased and then decreased. Under different nitrogen levels, the inhibition of Hg on three soil enzymes activity were as follows: urease > invertase > catalase. The results suggested that soil urease and soil invertase can be used as Hg pollution ecological monitoring index, early warning Hg pollution degree, while, soil catalase was not suitable as a soil Hg pollution warning index.

Abstract: This study was carried on about soil moisture and nutrients of meadow steppe, typical steppe and desert steppe ecosystems. The results showed that meadow steppes had the maximum soil moisture content, while the desert steppes had the minimum. This was because the three types of steppes had different soil types and physical characteristics, and these physical characteristics influenced soil moisture content to some extent. Compared with that in the meadow steppes and desert steppes, carbon and nitrogen content of soil of the typical steppes were the highest, and the differences in soil carbon and nitrogen among the three types of steppes were significant or obviously significant. They were due to the geographical environments, temperature and precipitation caused by a combination of factors.