To study effects of land management in winter on production,oxidation, and emission of CH₄ from the paddy field during the following rice-growing season, indoor incubation and field experiments were carried out to measure CH₄ production potential, CH₄ oxidation potential, and CH₄ flux in Treatments DF (drained fallow), DW (drained with wheat planting), and FF (flooded fallow). Results show that no significant difference in CH₄ production potential was observed between Treatments DF and DW (P>0.05), but both were significantly lower than in Treatment FF (P<0.05). No significant difference in CH₄ oxidation potentials was observed among the three treatments (P>0.05). Compared with the effects of land management in winter on CH₄ oxidation potential, the effect of soil NH₄⁺-N content during the rice-growing season was more important. The mean CH₄ flux was much higher in Treatment DF than in Treatment DW (P<0.05), but both were significantly lower than in Treatment FF (P<0.05). The significantly higher CH₄ production potential in Treatment FF than in Treatment DF was the reason why the CH₄ flux in Treatment FF was much higher. The effects of land management in winter on CH₄ emission during the rice-growing season were mainly affected by CH₄ production potential rather than CH₄ oxidation potential.

Methane emission fluxes from late rice fields under different fertilization treatments were studied, using the static chamber-gas chromatograph techniques. Results show that compared to Treatment 1 (T1,no fertilization), all the other fertilization treatments increased methane emission. The average methane flux from Treatment 5 (T5,straw incorporation) and Treatment 4 (T4,increased nitrogen and phosphate) was 9.96 and 7.90 mg·m^-2·h^-1, respectively. Treatment 2 (T2,balanced fertilization) and Treatment 3 (T3,decreased nitrogen and phosphate) were just approximately 20% more than Treatment 1. In terms of accumulated seasonal methane emission, the treatments followed an decreasing sequence: T5>T4>T2>T3>T1, but no significant difference (P>0.05) was observed between T1,T2,T3 and T4. According to the analysis of related environmental factors, methane emission fluxes had an exponential function relationship with soil temperature at 5 cm depth, and had a positive correlation with thickness of the water layer (P<0.05). T2 was a fertilization model recommended for the local region after comprehensive consideration of the greenhouse effect and rice yield. Considering global warming potentials of CH₄ and rice yield, T2 was a recommended fertilization method under the local condition. Total fertilizer application of N, P₂O₅ and K₂O was 180,90 and 135 kg·hm^-2, respectively. Ammonium bicarbonate, with a split 70% of designed N mixed with total P and K₂O (calcium superphosphate and potassium chloride) was broadcasted on the field before transplanting as basal fertilizer,and urea was topdressed with 30% of total N at the tillering stage.

From the aspects of resources and environment carrying capacity,development intensity and development potentiality,an index system for regional development priority zoning is established and a comprehensive methodology for the zoning is put forth based on the state-space theory.The method is applied to zoning of the 14 cities at prefectural level of Hunan Province as basic spatial unit.Results show that except for various legally established nature reserves that are dotted outside the cities,all the provincial key and priority development zones are distributed mainly in the eastern and central parts of Hunan Province,while restricted development zones in the western part.The application of the state space method to the zoning truthfully not only reveals overall carrying capacities of the regions and provides scientific basis for strategic decision-making in optimizing regional spatial structure and arrangement and in programming sustainable development of the regions,but also sets up an example for development priority zoning in China.

The land use pattern of Xigu District,Lanzhou was selected as a study area for analysis of variation of landscape index with grain size from the landscape level and type level,using 14 commonly used landscape indices and 2005 SPOT 5 remote-sensing images and orthographic aerial images.The study area delineated digitally into regular grids,200 m × 200 m,of which SHDI was worked out one by one,and spatial structure characteristics of the diversity of Xigu District were determined and analyzed with the semi-variogram method.Results demonstrate that 10 m was an intrinsic observation scale for land use landscape of Xigu District.The characteristics of landscape types and landscape patterns of the study area varied significantly with the increase in grain size,reflecting certain scale dependence.Landscape indexes of the townships (towns and neighborhoods) displayed differentiation characteristics of urban-peri-urban-countryside and apparent gradient variation.Spatial distribution of the diversity of Xigu District is a kind of spatial correlation of moderate strength.Areas of high values are distributed mostly alongside the Yellow River.

To study and compare the circular agriculture system of "dairy cattle-biogas-forage"(Mode Ⅰ) with the conventional dairy farm system (Mode Ⅱ) in ecological and economic benefit,emergy analysis method is used.Results show that the net energy yield ratio in Mode Ⅰ was 4.06,lower than that (4.13) in Mode Ⅱ.The emergy sustainable development index was 10.27 in Mode Ⅰ and 9.57 in Mode Ⅱ,suggesting Mode Ⅰ is more capable of sustaining development than Mode Ⅱ.The environmental loading ratio of Mode Ι was 0.11,lower than that (0.12) of Mode Ⅱ,and the emergy waste ratio was 21.72% in Mode Ⅱ but 0 in Mode Ⅰ,suggesting that Mode Ⅰ creates less pressure on the environment than Mode Ⅱ does.The feedback ratio of yielded emergy was 30.63% in Mode Ι but 0 in Mode Ⅱ,suggesting that Mode Ⅰ is higher in self-organizing ability.The net income of ModeⅠwas 1.13 times that of Mode Ⅱ,but the output-input ratio of Mode Ⅰ was 97.64% of Mode Ⅱ.Analysis of the eco-economic benefit of Mode Ⅰ based on the emergy-monetary value showed it was close to the actual economic benefit.Therefore,Mode Ⅰ can be characterized by less environmental pressure,higher self-organizing ability and high sustainable development capability,but it still needs to further optimize its system internal structure and improve its productivity.

Aiming at the problem of lack of water monitoring data of medium and small river basins in the countryside of North China, a project was carried out based on the findings of field surveys and the local statistics yearbooks, to calculate agricultural non-point source pollution load of 10 administrative villages in Dasuhe Township,using the export coefficient method, and in verification of the data obtained in the field survey and their relationship with pollution load, evaluation of the pollution sources was done, using the equiscalar pollution loading method, to obtain comparative equiscalar pollution loads on the same scale. Cluster analysis of the findings and results were obtained. The 10 villages were divided into 4 types in terms of agricultural non-point source pollution, and characteristics of each pollution source was analyzed.Results of the evaluation show that the Dasuhe Village ranked first in contribution to the load of domestic pollution and livestock dejecta pollution, and the Xiaosuhe Village did in contribution of the load of farmland chemical fertilizer pollution. The cluster analysis also demonstrates that the mean value of the equiscalar pollution loads of the 4 types of agricultural non-point source pollution was 51.05、95.80、236.41、185.69 m³, which indicates that relative differences are exsiting between villages in agricultural non-point source pollution.

Seasonal distribution of chlorophyll-a and its relationship with environmental factors and primary productivity were investigated during the period from May 2006 to February 2008 in waters of the Pearl River Estuary.Results show that no significant difference was observed between chlorophyll-a contents in the surface layer,in the sublayer and in the upstreams;chlorophyll-a content in the surface layer was found to be obviously higher in summer and spring than in fall and winter,while no significant difference was observed between sites.A similar trend of the variation of the primary productivity was observed in waters of the Pearl River Estuary.Pearson correlation analysis shows that chlorophyll-a concentration was significantly correlated with phytoplankton cell density and primary productivity.Environmental factors affecting chlorophyll-a content varied sharply with site and season.

Based on the sampled distribution data of Solidago canadensis in northern hemisphere,research was carried out to predict potential distribution of Solidago canadensis in China using the MaxEnt model as prediction model,and temperature and precipitation as environment variables.Results show that Solidago canadensis may infest an area much larger than that of its actual distribution now,suggesting that Solidago canadensis will continue to expand in China.Shanghai,Jiangsu,Zhejiang,Anhui,Shandong,Henan,Hubei,Hunan,Jiangxi,Fujian,Chongqing,Guizhou,eastern Sichuan,northern Guangdong and Guangxi,northeastern Yunnan,southern Shanxi and Shaanxi are the main suitable areas.Effective measures must be taken to protect these areas and others from Solidago canadensis invasion.

Chinese fir (Cunninghamia lanceolata) plantation is one of the main vegetations in the Simian Mountain of Chongqing.Chinese fir is also one of the main species of trees afforesting the area.Based on the data from the survey of a typical Chinese fir plantation in the area,species diversity of the Chinese fir community was analyzed using richness index,Shannon-Wiener index,Simpson index and Pielou evenness index.The existing Chinese fir community in the area can be divided into 2 formation groups (Chinese fir plantation and mixed Chinese fir-broadleaved forest),8 plant formations and 10 associations.Results show that the Chinese fir community is formed of arbor tree,shrubbery and herb layers.In the Chinese fir plantation,the three layers demonstrate a declining trend in richness,diversity and evenness indices,i.e.shrub layer>herb layer>arbor layer,while in Chinese fir mixed wood,the trend in richness index goes as shrub layer>arbor layer>herb layer;and in diversity index as shrub layer>arbor layer>herb layer;and however,the trend in evenness index is rather complicated without any of uniform law.With the rise in altitude the richness index of the Chinese fir community regardless of layers declines as a whole while their diversity indexes increase and display a certain law within a given region,that is,declining with the rising altitude where below 1 180 m,but fluctuating within the range between 1 180 m and 1 351 m,and declining again where above 1 351 m.The change in evenness index with all the layers is rather complicated and has no clear rule.

A simulation experiment was carried out to study effect of Eichhornia crassipes on removing nitrogen and phosphorus from eutrophicated water as affected by hydraulic loading (0.14,0.20,0.33,1.00 m3·m-2·d-1). The average concentrations of total nitrogen (TN), ammonia-nitrogen (NH₄⁺-N), nitrate-nitrogen (NO₃^--N) and total phosphorus in the influent were 4.85,1.33,2.92 and 0.50 mg·L^-1, respectively during the experiment. Results of the experiment show that the effect of the Eichhornia crassipes purifying system was satisfactory. When the hydraulic loading was low (0.14 and 0.20 m3·m-2·d-1), the average concentrations of TN, NH₄⁺-N and TP in the effluent all met the national standard for surface water body quality Ⅳ(GB 3838-2002). But when the hydraulic loading was raised to 1.00 m³·m^-2·d^-1, the average concentrations of TN, NH₄⁺-N, NO₃^--N and TP in the effluent increased significantly. Although the removal rates of TN and TP decreased,the load removal rates of TN and TP increased with the increasing hydraulic loading for the Eichhornia crassipes purifying system. For the four hydraulic loadings (0.14,0.20,0.33 and 1.00 m³·m^-2·d^-1), the average removal rates of TN and TP by the system were 84.95% and 80.65%,73.87% and 73.04%,51.60% and 64.05%,30.77% and 47.79%,respectively,that is,decreasing with rising of hydraulic loading,and the corresponding for TN and TP loading removal was 0.58 and 0.06,0.72 and 0.07,0.83 and 0.11,1.47 and 0.23 g·m^-2·d^-1, respectively, that is,increasing with rising of hydraulic loading. Comprehensively considering removal efficiency and wastewater treatment capacity, the hydraulic loading should be controlled at 0.33 m³·m^-2·d^-1 for the Eichhornia crassipes purifying system in conditions like this experiment.

Effects of Ipomoea aquatica cultivation on artificial floating rafts on water quality of intensive aquaculture ponds were studied using total phosphorus (TP), total nitrogen (TN), orthophosphate phosphorus (PO₄^3--P), nitrate nitrogen (NO₃^--N), nitrite nitrogen (NO₂^--N), ammonium nitrogen (NH₄⁺-N), COD_Mn and chlorophyll-a (Chl a) as main water quality indexes,and its mechanism of purifying the water was explored in an experiment. Results show that the yield of Ipomoea aquatica, harvested four times,r eached as high as 69 618.0～73 161.6 kg·hm^-2. In Treatments 10% and 20% (refers to coverage of the pond by Ipomoea aquatica) 27.51 and 52.35 kg·hm^-2 of TN and 2.83 and 5.39 kg·hm^-2 of TP were, respectively, removed with the harvest of Ipomoea aquatica. In terms of the water quality indexes, Chl a, TN, NH₄⁺-N, NO₂^--N, NO₃^--N, TP, PO₄^3--P, and COD_Mn, the three treatments followed a decreasing order of CK > Treatment 10% > Treatment 20%.And the removal rate of Chl a, TN, NH₄⁺-N, NO₂^--N, NO₃^--N, TP, PO₄^3--P, and COD_Mn in Treatment 20% varied in the range from 15.16% to 49.02%,from 9.04% to 36.56%, from 19.23% to 46.34%,from 22.76% to 47.74%,from 13.33% to 56.52%,from 33.33% to 45.10%, from 27.27% to 48.15%, and from 3.13% to 19.05%, respectively. Fish survival rates in the treatments improved significantly as is compared with that in the control. So it was obvious that in ponds rearing fries of crucians,bighead carps and grass carps, cultivating Ipomoea aquatica on artificial floating rafts could accelerate water material cycling and strengthen self-purification capability of the water body.And it is advisable to set coverage of the pond by Ipomoea aquatica at 20%.

Effect of immobilized Rhodopseudomonas sphaeroides treating cadmium (Cd) and chromium (Cr) containing wastewater was investigated and technological conditions for the immobilized bacteria to adsorb Cd and Cr ions were optimized in treating electroplanting wastewater continuously in a bioreactor. Results show that the bacteria immobilized in gel complex with 20 g·kg^-1 of zeolite and 20 g·L^-1 of sodium alginate were significantly better than free bacteria in removing Cd and Cr from the wastewater. Orthogonal experiments were conducted to optimize technological conditions for wastewater treatment.It was found that pH of the wastewater and inoculation rate of the bacteria were two major factors affecting heavy metals rermoving efficiency. When pH of the wastewater containing 40.00 mg·L^-1 Cd to be treated was 6.0 and inoculation rate of the bacteria 10.00 g·L^-1, Cd removing rate reached 96.68%. Results of four cycles of sorption-desorption reveal that immobilized bacteria could last three cycles. Its Cd removing rate might still come up to 51.20% in the third cycle. In the bioreactor,immobilized R.sphaeroides was used to treat electroplating wastewater containing 92.61 mg·L^-1 Cd. Three hours of treatment removed 98.80% of the Cd in the wastewater and over 90.00% of other heavy metals (Cu, Au and Ni) as well.

In order to explore how to rationalize the use of land polluted by heavy metals,coupled with an indoor pot experiment,a field experiment was carried out on Chongming Island,Shanghai to study effects of combined pollution of Cd and Pb on soil enzyme activity under different types of land use.Results show that the soil enzyme activity is lower in farms,residential areas and some other lands seriously affected by human activities than in wetlands,forest lands and riversides and lands which are rich in water supply and less disturbed by human activities.Significant positive correlations were observed between soil urease,phosphatase and dehydrogenase in activity (P<0.01),and soil urease was rather sensitive to Cd and Pb.Soil enzyme activity was also found to be positively related to organic matter (P<0.05).At low concentration,combined pollution of Cd and Pb showed a positive effect on soil enzyme activity,while at high concentration a negative impact.

Effect of addition of vermicompost on anaerobic digestion of corn stalk in biogas production was investigated with total solid (TS) concentration 50 g·kg^-1 and fermentation temperature 35 ℃. It was found that when corn stalk was in the digestor alone, the cumulative biogas yield per gram TS was 333.3 mL·g^-1 and the cumulative methane yield per gram TS was 202.0 mL·g^-1, but when vermicompost was added (1 : 1 in TS mass ratio), their outputs were increased by 20.0% and 35.5%,reaching 400.0 and 269.6 mL·g^-1, respectively. Moreover,the phenomenon of acidification disappeared during the process of fermentation.All these demonstrate that vermicompost is a suitable amendment in anaerobic digestion of corn stalk for biogas production.

A systematic introduction is presented to key problems and their countermeasures in screening analysis of persistent organic pollutants (POPs) in environmental samples using EPA 8081A and EPA 8082 methods,covering the double-column system for gas chromatographic analysis and validation of POPs,decomposition of DDT and endrin in the sample injection system and its countermeasures,rapid identification of multi-peaked compounds,such as polychlorinated biphenyl (PCBs),chlordane and toxaphene with empirical methods,such as visual recognition method,chiral method,transparent copy film method,etc.,key factors affecting the accuracy of quantification of multi-peaked POPs,such as PCBs,chlordane and toxaphene with the external standard method and requirements of quality control.It is,therefore,suggested that a library of standard samples and standard chromatographs of POPs be established in light of the characteristics of POPs pollution of the environment of China,so as to provide the survey and environmental monitoring of POPs pollution in China with effective technical support.

Effects of environmental conditions on bio-degradation of thifensulfuron was studied in laboratory. Results shown that bio-degradation rate of thifensulfuron was positively related to soil temperature and moisture content, but negatively to the initial concentration of thifensulfuron applied. The higher the soil temperature and the moisture content, the higher the degradation rate;but the higher the initial thifensulfuron concentration, the lower the degradation rate. The degradation rate increased by 2.9 times, when the temperature rose from 5 to 35 ℃. The half-life of thifensulfuron decreased to 2.6 from 7.6 d when the soil moisture content rose from 25% to 75% in saturated water content, but increased from 3.1 to 7.6 d when the initial application rate of thifensulfuron rose from 2.5 to 10 mg·kg^-1.

By observing marsh wetlands and their surrounding dry farmlands for comparison,effect of marsh wetlands on localized micro-climate is analyzed.Results show that marsh wetlands,compared with their surrounding dryland,are lower in temperature but high in humidity in the surface layer,displaying a significant "cold-humidity island" effect,which varies with elevation.The closer to the land surface,the more significant the effect.The field observation from June to September found that the "cold-humidity island" effect was relatively more obvious in July and August.By comparing the marsh wetlands with the dryland around in diurnal variation of temperature and humidity,it was found that the effect was more significant during the time period between 12:00 and 14:00.