[Effects of light-felling on non-growing season greenhouse gas emission from soils in Korean pine forests in Maoer Mountains, China.] / é€å ‰æŠšè‚²å¯¹æ¸©å¸¦å¸½å„¿å±±çº¢æ¾æž—éžç”Ÿé•¿å­£åœŸå£¤æ¸©å®¤æ°”ä½“æŽ’æ”¾çš„å½±å“.

Non-growing season soil greenhouse gas emission may play an important role in the forest ecosystem carbon and nitrogen cycle. However, it is not clear about the effects of the cutting distur-bance on soil greenhouse gas emissions during non-growing season. The CO2, CH4 and N2O fluxes and related environmental factors (soil temperature, water content, carbon and nitrogen, etc.) were monitored in the Korean pine plantation (fifty year-old) under different light-felling manners (control, no cutting; the half light-felling, cutting 50% of broad-leaved trees in canopy; the whole light-felling, cutting 100% of broad-leaved trees in canopy), using static chamber technique and gas chromatography during non-growing season in Maoer Mountains of China. The main aim was to reveal the influence of cutting disturbance on soil greenhouse gases emission during non-growing season and its controlling factors. The results showed that the whole and half light-felling manners significantly decreased CO2emission flux by 21.0% and 22.8%, and N2O by 23.5% and 11.2%, and decreased CH4uptake by 16.0% and 16.4%. The contribution of non-growing season CO2, CH4 and N2O emission to annual total was 11.7%-14.2%, 13.1%-17.0% and 63.9%-72.6%, respectively. Light-felling manners decreased annual cumulative contribution of CO2 by 1.4%-2.5%, that of CH4 by 0.7%-3.9%, but increased that of N2O by 2.4%-8.7%. Furthermore, light-felling increased the correlations of soil CO2 fluxes with soil temperature, soil water content, nitrate and ammonium, and decreased its correlation with soil organic carbon content. Light-felling increased the correlations of soil CH4 flux with soil water content, soil pH, soil organic carbon, ammonium, and decreased its correlation with nitrate. Light-felling increased the correlations between soil N2O flux and soil temperature, decreased the correlations with nitrate and ammonium, and changed the positive correlation with soil pH to negative. Therefore, light-felling had significant effects on the emission fluxes of the greenhouse gas during non-growing season, with the whole light-felling decreased more soil N2O emission flux than the half light-felling.

[Characteristics and effect factors for sorption of trichlorobenzene on sediment in Huaihe River (Jiangsu reach)].

The characteristics for sorption of trichlorobenzene on sediment in Huaihe River (Jiangsu reach) was studied. It was also in vestigated at the same time that some factors of influence on the sorption, such as initial consistence of adsorbate, concentration of adsorbent and pH value, by ortho-experiment. The results indicate that the sorption isotherms of trichlorobenzene to sediment in Huaihe River (Jiangsu reach) are linear in the experiments condition,and distribution plays a leading role. The affected degrees of different environmental factors are different for sorption of trichlorobenzene on sediment in Huaihe River. The results of ortho-experiment are analysis with SPSS(Statistical Package for the Social Science) and the results are indicate that the affection of initial consistence of adsorbate is the biggest in all environmental factors,and initial consistences of adsorbate have expressly significant influence for sorption of trichlorobenzene on sediment in fresh water, and yet the pH has almost no influence for the sorption of trichlorobenzene on same sediment.

[Analysis on the removal efficiency of phosphorus in some substrates used in constructed wetland systems].

Constructed wetlands are widely used to purify wastewater in some developing countries. As filter substrates in such wetland, these substrates play important role on removal of pollutants from wastewater. Selecting suitable substrates is one of the effective ways to improve the performance of constructed wetland on treating wastewater. In this study the phosphorus adsorption capacities of sand, zeolite, vermiculite, two clay soils, two industrial by-products named steel slag and fly ash are examined for their potential use as substrate in constructed wetland. Both Freundlich and Langmuir adsorption isotherms are very fit for describing the adsorption characteristics of these substrates. Two industrial by-products including steel slag and fly ash have higher phosphorus adsorption capacity, which had 50490 and 17934 mg x kg(-1) respectively. Followed vermiculite, two clay soils named yellow cinnamon and xiashu loess with phosphorus adsorption capacity of 3473, 1893.7 and 1582 mg x kg(-1) respectively. The zeolite and sand had the least phosphorus adsorption capacity with 813.7 and 302 mg x kg(-1) respectively. The experiments on purifying phosphorus from synthesize domestic sewage using these substrates also demonstrate this conclusion. The ability of removal phosphorus of these substrates have closely relationship with their makeup and chemical properties such as pH, total calcium and reactive calcium, reactive Fe, Al including poorly coastal and amorphous Fe, Al oxide. The steel slag and fly ash with higher reactive Ca, such as calcium oxide, have better adsorption capacity of phosphorus than other substrates, and the substrates which contained more reactive Fe also have a better ability of adsorption phosphorus than others. To assess the environmental risk for using these substrates above, the phosphorus de-sorption characteristics of these substrates are also studied. The process of phosphorus desorption quickly reached equilibrium in no more than 4 hours in the experiments, the ratio of desorption and adsorption of phosphorus in substrates above is lower except sand. To take suitable measures to manage substrates above, the risk of pollution of phosphorus form these substrates will be controlled.