Mine areas are highly affected by human activities,which aggravate soil erosion,disturb ecology and pollute the environment,thus causing land degradation,soil quality declining and biodiversity diminishing. How to control these problems has become a new challenge to China in managing the environment and restoring the ecology of mine areas. For that end,it is essential to identify and determine major factors driving land degradation in mine areas. Through comprehensive review of the researches on concept,types and causes of land degradation in mine areas,the boundaries of mine fields were further defined,the connotation of land degradation in mine areas clarified and main driving factors of the land degradation in mine areas,such as ecological destruction,environmental pollution and natural erosion,etc.. On such a basis,land degradation in mine areas is divided into three types,i. e. Type Ⅰ—caused by ecological destruction,TypeⅡ—caused by environmental pollution,and Type Ⅲ—caused by natural erosion. An index system and a set of approaches to the investigation of factors driving land degradation in mine areas has been put forth.

A review is presented of classification,sources and basic properties of natural carbonaceous geosorbents（ CG）and mechanisms and features of their sorption of typical organic pollutants. The organic pollutants discussed here include polycyclic aromatic hydrocarbons（ PAHs）,polychlorinated biphenyls（ PCBs）,polybrominated diphenyl ethers（ PBDEs）,various pesticides and antibiotics,and also a number of polar,semi-polar,non-polar（ apolar） and ionic compounds,all quite extensive in representativeness. The Van der Waals force existing between CG-type materials and organic chemicals contributes significantly to the adsorption of the latter by the former,however,the force may be affected by properties（ like pore structure,characteristic groups） of the CG material and a desorbate molecular characteristics（ like molecular structure,functional groups）. Insight into mechanisms of CG adsorbing these typical organic compounds and their affecting factors will be of great significance to environmental risk assessment and remediation of contaminated soils and groudwater.

Based on the PM_{2. 5} data published by 114 cities of China in winter（ from December 2013 to February 2014）,differences in spatial distribution of PM_{2. 5} concentration in winter between the cities and their affecting factors were studied by means of spatial auto-correlation analysis,Kriging interpolation and stepwise regression analysis. Results show that during this period of time,the spatial distribution of PM_2.5 concentration was characterized by clustering of high values,clustering of low values and clustering of low values in high-value domains; the overall Moran＇s I was 0. 27; PM_2.5 concentration displayed a rising first and then declining trend from North to South and from the inland to the coast; and high PM_2.5 concentration was mainly distributed in North China Plain,the middle-lower reaches of the Yangtze River and Guanzhong Plain of Shaanxi,where the mean concentrations were all beyond 150 μg·m^- 3and reached as high as 250 μg·m^{- 3}. Multiple factors stepwise regression analysis shows that the impact of anthropogenic activities was significant on distribution of high PM_2.5 concentrations（ 〉150 μg·m^{- 3}）,but not on that of low concentrations（ ≤75 μg·m^{- 3}）. The dense population and GDP of the secondary industry in the cities were the two main factors affecting distribution of high PM2. 5concentrations,while the area of built districts in the city area,the total population at end of the year of the whole city and the area of paved roads in the city area,were the major factors causing differences between cities in distribution of PM_2.5 concentration.

China is blessed with abundance of crop straw,of which the disposal by burning in open fields results in waste of resources and serious air pollution forming haze. The practice in Jiangsu was cited as a case for study. A "pressurestate-response"（PSR） model was developed based on the Boston matrix and used to analyze the air pollution caused by open-airstraw burning in 13 prefecture-level cities of Jiangsu Province during 2010- 2012 for pressure,state and response of the practice. Results show that although Jiangsu Province achieved remarkable results in banning open-air straw burning,the pressure of banning the practice to reduce air pollution was still quite high in almosthalf of the cities,and in most of the cities still existed much room for improvement of comprehensive utilization of straw resources. In Nanjing,attention should be given to comprehensive utilization of crop straw,which should be improved in comprehensive utilization level. In South Jiangsu,the crop straw utilization rate was quite high,but there was still much room for improvement of the utilization,However,it is still essential to enforce the policy of banning straw burning in open fields. In Central Jiangsu,the utilization of crop straw resources was rather simplex in method,so is necessary to shift its focus on multiplying ways of crop straw utilization. In North Jiangsu,the pollution pressure from straw burning was very high. Therefore,rigid policies of banning straw burning should be enforced along with development of comprehensive utilization of its crop straw resources.

A survey of the situation of the rural sewage treatment plants( RSTP) in 67 counties of Zhejiang Province was conducted by means of questionnaire,and then statistical analysis was performed for status quo of the facilities,covering power,treatment technology,standard to observe,operation mode and source of funds,etc.. Besides,exploration and analysis was done of standards for discharge of treated sewage from the plants and long-term nature of the operation,maintenance and management of RSTP. Results show that currently,the RSTP in Zhejiang Province are dominantly medium and small in scale( 30- 60 t·d^-1),and about 80% of the RSTP adopt the technology of unpowered anaerobic artificial wetland and observe Grade B criteria of the standard for sewage discharge( GB 18918-2002); the plants are generally run and maintained by their respective home villages or townships at an average cost of nearly RMB 13 000 Yuan·a-1. It is,therefore,suggested that Zhejiang Province formulate province-specific standards for discharge of treated waste water from RSTP as soon as possible with a proper number of indexes,which may be a little bit looser than Grade A criteria of the standard GB 18918-2002 and mechanisms of long-term nature for defining responsible parties,funding and managing third-party-run RSTP in Zhejiang Province as soon as possible,too.

Based on the results of the first and second pollution survey and 78 monitoring data,using methods of questionnaire and field survey,the present situation of mulching plastic film pollution were investigated and the countermeasures were analyzed. The results indicate that the total quantity of mulching film used wes about 152 025 t and the amount of mulching film residues was about 44 574 t in 2013,and the pollution distribution had obviously regional differences( i. e.the serious pollution area lied in the central Loess Plateau,and then the eastern Loess Plateau,the Hexi Corridor,the Longnan Mountains area,the Tianshui area and the Gannan Pasturing area,respectively). The results also prove the pollution of mulching plastic film varied with crops,and the level of mulching residues in corn field was obviously higher than other crops. In addition,the results reveal that the amount of mulching residues are mainly affected by the size of residual film fragments,the mulching film thickness,the cultivated land utilization way,the distance of farmland to the village,the length of using mulch film time( e. g. the mulching fragment residues of 0- 30 cm in size are respectively 27. 62,30. 78 and 42. 26 kg·hm^-2 within 1- < 10,10- < 20 and 20- 30 years),the crops variety and the mulching film techniques.By 2013,Gansu Province has established a complete system of waste mulching film recycling,sets up 231 recycling companies and 2 130 outlets,the mulching residues recovery rate was 70. 7%. Meanwhile,some effective measures have been carried out such as increasing mulching film thickness,adjusting the planting patterns,increasing organic fertilizer application,reducing mulch film repeated use,using manual and mechanical collecting and so on,and the mulching residues and pollution have decreased greatly in recent years.

Implementation of agricultural land use policies may greatly impact regional agriculture in production mode and development path. A case study of the Dianshan Lake region of Shanghai was performed using a multi-criteria analysis framework for land use policy effects and a comprehensive index system encompassing societal,economic and ecological factors established in the study,to simulate and evaluate effects of agricultural land use in different scenarios( basic scenario,benchmark scenario and scenarios of three different policies),with the scenario analysis method and Techno GIN model. Results show that the policy of soil-testing-based fertilizer recommendation encourages the farmers to raise K / N ratio in fertilization,and as a result,the yield of rice increases somewhat,but the policy does not significantly reduce total N input and consequent N leaching. However,the policy of site-specific nutrient management( SSNM) further rationalizes the K / N ratio,while reducing total N input and consequent N leaching,but it calls for too much labor,which limits implementation and popularization of the policy. The major effect of the moderate-scale management policy is reduction of labor input,thus freeing more rural labor for off-farm employment. The methodological framework as presented here proves to be a useful tool for evaluation and prediction of agricultural land use effects in China,and the findings in this study may serve as reference for the scientific management of suburban agricultural sustainable development in Shanghai.

Longdun Reservoir watershed was chosen as a case for study to predict nitrogen and phosphorus pollution load using GIS(geographic information systems)  and USLE(universal soil loss equation).The watershed was divided into subwatersheds using the subwatershed division module of SWAT model. And the non-point source pollution of the subwatersheds were evaluated,using the indices of equal-standard pollution load and equal-standard pollution intensity. In the end,nitrogen and phosphorous pollution loads were graded through cluster analysis and critical source regions were defined. Results of the study show that in the studied watershed,the pollution load and intensity of total phosphorus(TP) is124. 25 t and 4. 95 t·km^-2,respectively; and the pollution load and intensity of total nitrogen(TN) is 274. 87 t and10. 96 t·km^-2,respectively. The equal-standard pollution load of the whole watershed is 2. 76 × 10⁹m³,of which 2. 75× 10⁸m³ is equal-standard TN pollution load accounting for 9. 96% and 2. 48 × 10⁹m³,is equal-standard TP pollution load,accounting for 90. 04%,indicating that TP is the dominant non-point source pollutant of the watershed. TN and TP pollution loads and pollution load per unit area varies with type of land use. Upland is the highest in both and hence the major source of the non-point source pollution in the Longdun Reservoir watershed.

Generally,rainfall-runoff is thought to be the major impetus leading to the export of nonpoint source pollutants.Based on the preliminary studies on loss of pollutants from facility farmlands,rainfall-runoff and irrigation are two major driving factors leading to non-point source pollution from facility farmlands. To quantitatively investigate non-point source pollution load of the facility farmlands in the downstream of the North Canal,the Beichen Shuangjie Greenhouse Grape Demonstration Park was cited as object of the study. Analysis of the models for rainfall-runoff pollution load (SCS,USLE,adsorbed nitrogen and phosphorus pollution loads and dissolved N and P pollution loads) and the model for irrigation pollution load (model with modified export coefficient)  was done and modification of the models made. Then the modified models were used to simulate and analyze run-off and irrigation processes for assessment of pollution load from the park. Results show that the export load of adsorbed nitrogen and phosphorus from the park reached 40. 98 and 1. 42 kg·a^-1,respectively,in the rainy season,while the load of dissolved ones was 628. 77 and 4. 57 kg·a^{- 1,}respectively; the load of total nitrogen,total phosphorus,ammonium nitrogen and nitrate nitrogen during the irrigation period was 182. 15,2. 56,60. 49 and 62. 82 kg · a^-1,respectively. The study demonstrates that the modified models are good in simulation and worth further extrapolating.

From the angle of contribution of eco-system to environmental purification,the value of the environmental purification function of a coastal-terrestrial ecosystem is defined as sum of the values of its functions of pollution purification and air regulation. To establish a model for assessing value of the environmental purification function of a coastal-terrestrial ecosystem,six ecological functions of the system,i. e. release of O₂,fixation of CO₂,purification of sulfides,purification of nitrogen-oxides,purification of fluorides and arrest of dust as evaluation indices. With Huanghua City cited as a case for study. Values of the purification functions of nine categories of eco-systems in the city,such as farmland,garden,grassland,wetland,etc. were assessed using the market price method and shadow price method. Results show that the value of the environmental purification function of the coastal terrestrial eco-system of Huanghua City was quite high,reaching up to 1 634. 54 million Yuan. In terms of purification function value per unit area,the functions followed an order of O₂ release > CO₂ fixation > pollutant purification; and the categories of eco-systems,such as farmland,garden,and grassland were quite high in O₂ release function value,reaching about 0. 67 Yuan·m^-2; and the eco-system of saline land was the lowest in CO₂ fixation function,being about 0. 01 Yuan·m^-2 only.

 A systemic survey of community structure of waterfowl in the Yellow River Delta Nature Reserve (YRDNR)was conducted during the waterfowl migration and wintering periods from October 2014 to January 2015 using the line transects method. The survey consisted of 8 line transects and 40 observation points. Results show that (1) 54 species,6 orders and 14 families of waterfowl were recorded during the autumn migration period,including 5 species under the national grade one priority protection,and 8 species under the national grade two priority protection,while 31 species,5 orders and7 families of waterfowl were recorded during the wintering period,including 1 species under the national grade one priority protection,and 4 species under the national grade two priority protection; (2) the waterfowl in the reserve during the two periods was dominantly of Anseriformes (Anser fabalis,Anas poecilorhyncha,Anas strepera and Anas platyrhynchos); and waterfowl like Grus japonensis,Ciconia boyciana and Cygnus Cygnus were held to be rare species,but still considerable in population in the reserve;(3) in terms of number of species,populations and Shannon-Wiener diversity index,the waterfowl was higher in the autumn migration period than in the wintering period;(4) species and population of the waterfowl varied with the habitat,and natural waters were the major waterfowl distribution areas; and (5) the waterfowl in natural habitats or natural water areas was much higher in artificial habitats in term of the three indices. Similarity analysis shows that community structure of the waterfowl in natural habitats is higher in similarity than that in the artificial habitats.

With large-scale extrapolation of commercial cultivation of genetically modified crops,biosafety issues caused by pollen flow from genetically modified plants have become a growing concern the world over. A two-year controlled field experiment was carried out at the transgenic crop environmental safety experiment base in Xuzhou,Jiangsu focusing on pollen flow from transgenic winter wheat N12-1 containing a NIb8 gene for resistance of wheat yellow mosaic virus (WYMV).The base was established and authorized by the National Biosafety Committee of China for growing transgenic wheat for environmental biosafety assessments. To study influence of wind direction on pollen flow from the transgenic wheat,the field experiment was laid out in concentric circles and wheat pollen density monitored in eight directions around the pollen donor at different intervals. Results show that pollen density of transgenic wheat declined dramatically with increasing distance from pollen sources in eight directions,however,the declining rate varied significantly with the direction,and was relatively lower in the lee. Meanwhile,to investigate effect of size of the pollen source on pollen flow,two tracts of pollen source,different in size（ 100 and 400 m²） were set up in parallel and wheat pollen density was monitored in the lee. Results show that a big size pollen source may have a lower pollen density declining rate within a given range,as compared to a small size one. All the findings indicate that wind direction,wind speed and distance from the pollen source are the major factors affecting pollen flow from the transgenic wheat.

In a simulated nutrient-deficient soil (without fertilizer application or target insect stress),transgenic cry1 Ab /c rice HH1 (Bt rice) and its non-transgenic parental cultivar (CK rice) were planted for comparison of the two rice cultivars in ecological fitness. Results show that the Bt rice planted in either the simulated soil or the field followed a similar basic rule of cry1 Ab / c gene expression but the expression level of Bt protein was much lower in the former case. Bt rice showed significantly higher fitness benefits in plant height,chlorophyll content,leaf shape and root system development in most developmental stages than CK rice,and apparent positive effects of ecological fitness,as well,on reproductive parameters such as seed number per plant,seed number per spike,seed weight per plant and total weight per 1 000 seeds.All these findings suggest that Bt rice might exceed CK rice in survivability and reproductibility in nature,and hence it may pose some environmental risks.

Field investigations were conducted during the rice growing season to monitor residues of Cry1Ab/c protein in water and soil of paddy fields cultivated with Bt-shanyou63 (Bt- SY63) rice for years in a row,4 years in Wuhan,3years in Suizhou,3 years in Wuxue and 2 years in Xiaogan of Hubei and 3 years in Dezhou of Shandong,using the enzyme-linked immunosorbent assay (ELISA) method. Results show that no significant differences were found in concentration of Cry1Ab/c protein in water between the fields cultivated with Bt- SY63 rice for 2-4 years and those with SY63 rice (P>0. 05),and the highest residue of Cry1Ab/c protein was measured to be 0. 373 ng·mL^-1 only. Similar to residue in the water,residue of the protein in the soil,regardless of growth stage,was found below the detection limit of the testing kit（ 0. 25 ng·g^-1） in all the paddy fields,except for the field in Suizhou where 0. 261 ng·g^- 1was detected in the soil at the seedling stage,and the field in Dezhou where 0. 540 and 0. 361 ng·g^-1 was at the jointing and blooming stages,respectively,forming significant difference from the control fields. Besides,no significant difference was detected in residue of Cry1Ab/c protein in soil and water between fields different in Bt- SY63's cultivation history. It is,therefore,held that Bt- SY63 rice may release only a trace amount of Cry1Ab/c protein into the water and soil of the field after 2,3 or 4 years of cultivation of the crop in a row. However,the amount is so low that it would not result in accumulation of Cry1Ab/c protein in the water and soil of the field.

Field investigation was made in March 2013 of Dongtan (East Beach)  of Chongming Island to explore carbon sequestrating function of tidal wetlands and its key influencing factors at the Yangtze Estuary. Sampling sites in Dongtan were laid out with the grid sampling method and elevations measured. Soil samples were collected from the 0- 30 cm topsoil layers for analysis of soil organic carbon content,soil salt content,bulk density,soil moisture content,median particle size and p H. Based on the data obtained during the field investigation of Dongtan,spatial distribution of contents of soil organic carbon and their influencing environmental factors in the topsoil layer were analyzed and the soil organic carbon stock therein was assessed through Kriging interpolation with the aid of Arc GIS and through correlation and path analyses with the aid of SPSS. Results show that in the 30 cm topsoil layer,soil organic carbon density varied in the range of 1. 02-5. 22 kg·m^-2,averaging 2. 32 kg·m^-2,and the soil organic carbon storage reached 1. 15 × 10⁸ kg. Soil organic carbon content,total salt content,soil water content and NDVI index were all quite similar in spatial distribution,being high in the north and low in the south and high in beaches with high tide and low in beaches with low tide,while median particle size and soil bulk density displayed quite reversely in spatial distribution,being higher in the south and beaches with low tide than in the north and beaches with high tide. However,elevation and p H did not follow any rule in spatial distribution and varied slightly spatially. All the 7 investigated environmental factors were found to have close relationships with soil organic carbon content. Total salt content,in particular,which is the most important factor affecting soil organic carbon content in the soil of Dongtan.

Water is one of the key factors affecting CH₄ emission in wetlands. To investigate effects of soil moisture content and litters on CH₄ emission,an indoor incubation experiment was performed using peat collected from the Zoige Wetlands. The experiment was designed to have three treatments in soil moisture content [Treatment 60%（ unsaturated soil moisture,60% of soil water holding capacity）,Treatment 100%（ saturated soil moisture,100% of soil water holding capacity） and Treatment WDA（ wetting-drying alternation） ] and two treatments in litter（ with or without litters addition）.Results show that the effects of soil moisture and litters on CH₄ emission from the peat were significant. Compared to Treatment 60%,Treatment WDA was significantly higher and Treatment 100% the highest in CH4 emission. Addition of litters promoted CH₄ emission rate and cumulative emission in peat. CH₄ emission from the peat responded the most quickly to litters addition in Treatment 100%,not so quickly in Treatment WDA and the slowest in Treatment 60%.

To investigate physiological responses of Ulva linza to addition of N and P and its mechanisms,an experiment was conducted culturing Ulva linza in solutions different in N and P concentration for 10 days and then relative growth rate (R_r,g),contents of N,P,chlorophyll (Chl) and carotenoid (Car),Chl a/Chl b,Chl/Car and chlorophyll fluorescence parameters(CFP) were determined. Results show that in the solutions kept the same in P concentration (30 μmol·L^-1P),with rising N concentration,all the indices of the algae gradually increased except for P content which declined steadily,and both Rr,gand CFP peaked and when N content reached 500 μmol·L^-1,and Chl,Car and Chl a/Chl b did when N content reached 1 000 μmol·L^-1. However,in the solutions kept the same in N concentration (500 μmol·L^-1N),rising Pconcentration did not affect R_r,g or N content in the algae much,however,it did increase P content significantly in the algae,while the other indices varied just slightly. To sum up,compared with P,N is more important to growth,formation of photosynthetic pigment and photosynthesis of Ulva linza. In the solution with 500 μmol·L^-1N and 30 μmol·L^-1 P ( N/P 16. 67),U. linza grows the most healthily and when the water body is getting eutrophied,U. linza N and P enrichment capacity rises steadily,too.

Based on the measurements of heavy metals in the samples of sediments collected from 12 sampling points along the moat of Suzhou City of Anhui Province,pollution degrees of heavy metals (V,Cr,Ni,Cu,Zn,As and Pb) of the sediments in the moat were analyzed using Nemero index and sediment enrichment factor,and sources of the heavy metals identified using cluster (Pearson correlation coefficient) and factor analyses. Results show that Cu and Zn was quite high,Ni,As and Pb,moderate,and Cr,low to moderate in pollution degree,while V was nil. In terms of integrated pollution degree of the 7 heavy metals,the 12 sampling sites displayed an order of H7> H10>H3> H9 >H1>H11>H6>H5>H12>H8> H2>H4. Sampling site H7 ranks first in the order because it is quite close to the industrial zone,while Sampling site H4 ends the order because it is located near the juncture of the residential area with the moat. Cluster analysis sorts the pollutions of the 7 heavy metals into Category Ⅰ(Cu,Zn,As and Pb),Category Ⅱ(Cr,Ni) and CategoryⅢ (V) and the elements in each category are quite similar in geochemical process. Factor analysis of the rotated component matrix extracted 3 principal components  (PC1,PC2 and PC3) out of the heavy metal element variables,which tallied quite nicely with the result of the cluster analysis and were adequate to explain 90. 97% of the total variable. Specifically,PC1 (Cu,Zn,As and Pb) is typical of pollution from the transportation and the coal industry,PC2 (Cr and Ni) of machine manufacturing,and PC3 (V) of natural process.

Samples of soil（ soil profiles） and plants were collected from farmlands around a micro-sized lead-zinc mine in East China for analysis and evaluation of heavy metals pollution and further for health risk assessment of the pollution of vegetables to local inhabitants. Results show that the soil around the mining area was polluted by heavy metals to different degrees,and cadmium pollution was the most severe according to the single factor pollution index analysis. Only one out of the total 11 soil samples was moderate in pollution degree,and the rest were severe. The analysis of the soil profile that was the lowest in pollution degree revealed that the high heavy metals pollution of the soil was closely related to the mining activities,and to the soil parent material. The crops in the studied zone were all polluted by cadmium and lead to varying degrees. Long-term consumption of locally produced vegetables may have some potential health risk. Planting Morus alba is a reasonable utilization mode for polluted farmlands in the area.

To investigate soil accumulation of heavy metals in farmlands that have long been irrigated with sewage and its environmental risks,samples of the soil and wheat plants were collected from typical sewage irrigated farmlands alongside the Wangyanggou,a typical sewage irrigation river,for analysis of Cd,Pb,Cu and Zn contents,and status quo of the heavy metal pollution,potential ecological risks and potential health risks were evaluated. Results show that although the contents of Cd,Pb,Cu,and Zn did not exceed the limits set in the national standard,they were higher than the soil background values and those in the soil irrigated with clean water,indicating that heavy metal accumulation had already started. In about 23. 1% and 15. 4% of the wheat plant samples,the contents of Pb and Zn were higher than the standards.However,the contaminations of Cd,Pb,Cu and Zn were still in the safe range,indicating that the heavy metal contents had not yet reached their respective alarming levels. Potential ecological risk assessment shows that Cd was the highest in ecological risk coefficient,posing a moderate ecological hazard; and Pb,Cu and Zn posed slight potential ecological risks.Health risk assessment shows that none of the four heavy metals reached a significant level in single-factor health risk coefficient,but their integrated pollution risk index was higher than 1,indicating that there are certain potential health risks in this region,which are more hazardous to children than to adults. Therefore,the situation calls for adequate attention.

An outdoor pot experiment was conducted to study effects of biochar on Cd form and Cd uptake by rapeseed（ Xiangyou 27） in the heavily Cd polluted soil collected from a field nearby a metal melting plant in Hunan,relative to type and dosage of the biochar. In the pots,caragana biochar or bamboo biochar was amended,separately at a rate of0. 1% and 1%,7 days before rapeseed seedlings were transplanted. Then soil samples were analyzed for Cd forms and rapeseed plants were analyzed for Cd contents in various organs at the mature stage. Results show that amendment of biochar may reduce soil Cd availability and Cd contents in various organs of the plant. The effect of caragana biochar reducing Cd uptake and accumulation by the plant was more obvious than that of bamboo biochar. Moreover,the effect became more obvious with increasing biochar amendment rate. Compared with CK,amendment of biochar reduced the content of exchangeable Cd in the soil by as high as 16. 64%; and decreased the Cd concentrations in roots,stems,hulls and seeds of the rapeseed by as much as 34. 06%,39. 74%,33. 15% and 49. 81%,respectively. In short,Treatment of amendment of 1% caragana biochar is the most effective in the experiment.

To replore effects of temperature and duration of pyrolysis on physico-chemical properties of biochar,tea branches and twigs were used as raw material in pyrolysis under different temperatures（ 300,450,600 ℃） for 1 and 3 hours,separately,and the biochars were analyzed for properties and element composition. Results show that the biochars were highly porous in structure with a high specific surface area and fairly well maintained organization structure of tea branches and twigs. With rising temperature and extending duration of pyrolysis,the biochar increased in ash content,p H,organic carbon,total phosphorus,total potassium,total calcium,total magnesium and C / N ratio,but decreased in total nitrogen.Meanwhile,ash content was extremely significantly and positively related with pH and was the main contributor to alkalinity of biochar. In addition,the conditions of pyrolysis had significant effects on physico-chemical properties of the tea-twigderived biochar,and the effect of temperature was higher than that of duration. Moreover,the paper also discussed prospects of the application of the tea-twig-derived biochar in tea gardens,and the findings of the study may serve as reference for application of the biochar.

The straw of preceding rice was returned to field totally,and winter wheat was sowed with five N rate treatments（ 0,90,180,270 and 360 kg·hm-² applied to investigate the mineral N accumulation,straw N release,N balance and grain yield of winter wheat. The results show that mineral N accumulation amount in 0- 30 cm soil layer at overwintering stage increased with basal N application rates,as increased with top dressing N application rates in 0- 15 cm soil layer at anthesis stage. Mineral N residual was significantly higher than before planting when nitrogen rate was applied higher than180 kg·hm^-2 .The analysis on N balance further indicat that the soil net mineralization N was 48 kg·hm^-2 the amount of straw N release,plant N uptake,mineral N residual and apparent N losses increased as nitrogen application rate increased. The N loss ratio of N90,N180,N270 and N360 treatment was 27. 9%,37. 6%,43. 2% and 47. 6%,respectively. The loss of N mainly occurred before overwintering stage in N90 treatment,while in other treatments it was found after anthesis. There was no significant increase in yield when nitrogen rate exceed 180 kg·hm^-2 .Considering both the grain yield and ecological effect,we suggest that the proper amount of nitrogen application for late sowing wheat with total preceding rice straw returning is 180 kg·hm^-2 in those growing areas similar to this experimental condition.

With the development of biogas projects,a massive amount of fermentation residues has been produced in the rural areas of China. Hence how to recycle those residues and what their potential values are have attracted great interests from both scientists and engineers. Biogas slurry is supposed to be applied as fertilizer in rice cultivation. To explore effects of soaking rice seeds with biogas slurry on seed germination and growth of rice seedlings,rice seeds（ Oryza sativa）were soaked separately in biogas slurries different in concentration for 24 h before the seeds were sown into seed beds for germination,and germination rates and seedling growth was monitored for comparison between treatments different in concentration of biogas slurry used in soaking. Results show that in the treatment using 2% of biogas slurry,the seedlings increased their root number and shoot biomass,but decreased their root biomass. However,this treatment did not have much effect on seed germination rate and speed,shoot length,shoot diameter and root length of the seedlings. Treatments higher in biogas slurry concentration inhibited both seed germination and seedling growth. As the effect of biogas slurry on root was higher than on shoot,the seedlings in all the treatments had higher shoot / root biomass ratios than CK. Analysis of respiration rate of rice seedlings reveals that treatment of rice seeds with biogas slurry may have some negative impacts on germination of seeds at the late stage. So mechanism of biogas slurry affecting seed germination and seedling growth could be complicated. As a conclusion,it is recommended that cautions be taken in using biogas slurry to treat seeds in the early stage of rice cultivation.

 To explore for optimal conditions for SSR-PCR( simple sequence repeat anchored polymerase chain reaction) for Magnolia officinalis,the five factors that would affect PCR (DNA templates,primers,Mg^^2＋,dNTPs and Taq polymerase) were optimized to four levels using an orthogonal experimental design based on screening of SSR primers. Out of the70 pairs of primers isolated from Magnolia officinalis and its related species,13 pairs were picked out with distinct amplified bands and rich polymorphism. In terms of impact on PCR system at various levels,the five factors displayed an order of primer>Taq enzymecatalytic activity concentration >Mg^2＋> dNTPs> template DNA. The optimal PCR system for SSR analysis was the 25 μL^-1 system with template DNA being 2 ng·μL^-1,primer being 0. 6 μmol·L^-1,Mg^2＋concentration being 2. 0 mmol·L^-1,dNTPs concentration being 0. 5 mmol·L^-1 and Taq polymerase being 0. 03 U·μL^-1,and the best amplification program consisted of 4 minutes of predenaturation at 94 ℃,30 seconds of denaturation at 94 ℃,30 seconds of annealing at 48. 0- 59. 0 ℃（ annealing temperature depending on primers） for 30 seconds,1 minute of extension at 72 ℃,and 10 minutes of extension at 72 ℃ after 35 cycles of the preceding processes. The above findings may provide some technical parameters for using the SSR-PCR technology in studying population genetics and molecular ecology of the endangered species,Magnolia officinalis.

In preventing and controlling agricultural non-point source pollution,it is essential to take into account both pollution reducing effect of a technique and engineering construction-operation costs of the technique. AHP (analytical hierarchy process) coupled with GRAP (grey correlation degree process)  was used to select the most suitable ones out of the73 typical technologies for preventing and controlling agricultural (planting,livestock and poultry breeding,aquaculture) non-point source pollution available in the past 20 years in China. A total of 12 were obtained preliminarily in the light of pollutants (TN,TP,NH3-N,COD) reducing effects and construction-operation costs. Results show that for controlling non-point source pollution from farming,the technology of plant-microbe complex for treating field drainage is the best and followed by the technology of ecological buffering ditches; for controlling non-point source pollution from livestock an poultry breeding,the technology of wastewater land filtering system is the best and followed by the technology of artificial wetlands; and for controlling non-point source pollution from aquaculture,the technology of complex filling sequencing batch biofilm reactor is the best and followed by the technology of complex biological-ecological treatment. In light of the actual situation of the Taihu region,the technology of ecological buffering ditches is very suitable for controlling agricultural nonpoint source pollution with field drainage,the technology of wastewater land filtering system is treating wastewater from livestock and poultry breeding in the upper stream of the Taihu Lake Region,and the technology of complex filling sequencing batch biofilm reactor is for treating waste water from aquaculture. The AHP-GRAP method used in the selection is good enough to meet the demand for consideration of both pollution reducing effects and construction-operation costs in comparing and selecting agricultural non-point source pollution control technologies.