Abstract:Sustainability evaluation of regional cultivated land resources is important to guidance of agricultural production. With the aid of GIS techniques, like overlay analysis and multi-factor comprehensive weighing method, suitability evaluation of the cultivated land resources of the Poyang Lake region was conducted using 11 evaluation indices selected from the aspects of resource, environment, economy and society, based on the applicability assessment, field survey and data statistics. Results show that as a whole, the cultivated land resources of the region is quite high in utilization sustainability level, with 69.05% being high or moderate and only 5.23% being extremely low or un-sustainable, indicating that the region is strong in agricultural productivity, good in agricultural eco-environment and high in agricultural economic level. The findings of the study may be used as scientific basis for exploitation and protection of the cultivated land resources and restructuring of the agriculture of the region.

Abstract:31 topsoil samples (0~5 cm) were collected in Jiading District, Shanghai in light of diversity of landuse patterns and uniformity of spatial distribution. Magnetic susceptibility (χ _lf ) and heavy metal contents (Cu, Zn, Pb, Cd, Cr and Mn) of the samples were determined. Results show that the topsoils in Jiading District are generally enhanced in magnetic intensity, which varies much spatially within a range from 35.1×10^-8 m³ kg^-1~1 676.9×10^-8 m³ kg^-1, and is averaged to be 177.9×10^-8 m³ kg^-1. Moreover, the topsoilχ _lf also varies with the landuse pattern, and generally follows a decreasing order of industral soils > roadside soils > cultivated soils > forest soils. A close relationship between the enhancement of χ _lf and accumulation of heavy metals in the topsoils was also observed: Topsoil χ _lf values are in significant positive correlation with contents of Zn, Cr and Cd (p＜0.01), and with the integrated pollution indexes (p＜0.05) as well. The findings further suggest that the magnetic method can be used as an effective tool in monitoring and evaluating heavy metal pollution of the soils in Shanghai.

Abstract:Seasonal variation of salinity is typical of coastal saline soils. High water table and high salinity of the groundwater are considered to be the main cause of salt accumulation in the soil in winter and spring. Fortunately, an agro-ecosystem consisting of raised-beds and shallow pools is expected to be able to solve this dilemma. Raised-beds are built to lower ground water table, and shallow pools provide in winter brackish ice that can be used to mulch the fields. The mulching of brackish ice melts, leaching salt off from raised-beds, thus preventing surfacing of salt. In the experiment, to control melting speed of the ice, three treatments were designed, i.e. no mulching over on the ice layer, mulching with reed straw and mulching with non-woven fabrics. Variations of water content and salinity in the soil of the raised-beds were monitored, before and after melting of the ice and during the process of melting in the experiment. Results show that mulching with brackish water can not only inhibit accumulation of salt, but also decrease salinity and increase water content of the soil. In the treatment of no mulching on ice, the ice melted quickly, raising soil water content quickly in a short time, so its desalinizing effect was notable but not lasting. The treatment of mulching the ice with reed straw reduced evaporation of ice water, and deferred ice melting, thus prolonging desalinizing time. Compared with the foregoing treatment, the treatment of mulching with non-woven fabrics displayed a proper ice melting rate and the best desalinizing effect. In the three treatments at the time the ice mulching completely melted, the water content in the 0～20 cm soil layer increased by 44.5%, 42.8% and 68.5%, respectively, as against that in the soil without ice mulching and the desalinization rate reached 44.4%, 47.0% and 72.4%, respectively. The improvements in soil moisture and soil salinity create a suitable soil environment for crops, and provide a guarantee for successful implementation of follow-up amelioration of coastal saline soils.

Abstract:Site investigation, human health risk assessment and derivation of recommended soil remediation goal were conducted in suspected DDT polluted area of a former DDT manufacturing site in China. It was found that the chemicals of concern (COCs) in the area around the wastewater treatment tank of the plant were mainly p, p'-DDT, p, p'-DDD, p, p'-DDE, 1,4-dichlorobenzene, chloroform and chlorobenzene. In the soil on the north and east sides of the tank vertical translocation of COCs was obvious, whereas in other parts of the site COCs were only found in the 0～50 cm soil layer. Of the first five COCs, carcinogenic risk was beyond 10^-6. At some points non-carcinogenic hazard index of p, p'-DDT and chlorobenzene exceeded 1. Uncertainty analysis shows that soil ingestion and dermal contact accounted for more than 98% of the total risk of semi-volatile organic compounds such as p, p'-DDT, p, p'-DDD and p, p'-DDE, whereas, indoor air inhalation for more than 99% of the total risk of volatile organic compounds such as chlorobenzene, 1,4-dichlorobenzen and chloroform. Soil particle density, soil bulk density, and soil water content were sensitive parameters. The recommended soil remediation goal of p, p'-DDT, p, p'-DDD, p, p'-DDE, chlorobenzene, 1,4-dichlorobenzen, and chloroform are 5.84, 6.19, 4.36, 36.2, 0.55, and 0.02 mg kg^-1, respectively.

Abstract:Adsorption isotherms of the insecticidal protein of Bacillus thuringiensis subsp. kurstaki (Btk) in red soil and brown soil were determined using the equilibrium adsorption method. Based on the isothems, their adsorption equilibrium constants and thermodynamic parameters were calculated. Results show that in the range between 278K and 318K, the Btk protein adsorption isotherms in red soil and brown soil followed the Langmuir equation (R²﹥0.994 1), showing that Bt adsorption and adsorption equilibrium constant decreased with rising temperature, but separation factor constant (R_L) increased in the range of 0.218 1～0.580 1 in red soil and of 0.361 7～0.754 1 in brown soil, indicating that both were of preferential adsorption. Btk protein adsorption in the two soils was a spontaneous, exothermic, entropy-increasing process. In red soil the activation energy of adsorbed Btk protein ranged from 13.43～14.78 kJ mol^-1, while in brown soil it did from 10.89～11.47 kJ mol^-1. Under rising temperature, it increased along with adsorption free energy, which suggests that the adsorption of Btk protein by the soils is turning from a physical process into a chemical one.

Abstract:In a pot experiment, effects were investigated of inoculation with arbuscular mycorrhizal fungi isolated from soil of a mining area on root colonization and plant biomass, Cd uptake and distribution of marigold (Tagetes erecta L.) growing in soils applied with Cd at different rates (0, 20, 50 mg kg^-1). Results indicate that inoculation of the fungi significantly increased their root colonization and biomass of marigold plants. Plant Cd concentrations and uptake markedly increased with increasing Cd addition levels. For all the treatments, Cd contents were significantly higher in shoots than in roots, while with the same rate of Cd added Cd content was higher in the shoots of inoculated plants than of uninoculated control. Especially, in Treatment 20 mg kg^-1, the ratio of Cd content in shoot to that in root of inoculated plants was 3.90, while in control it was only 2.33. In general, inoculation with arbuscular mycorrhizal fungi isolated from contaminated soil AMF increases Cd uptake in plants and enhances Cd translocation from roots to shoots, showing a promise in Cd phytoextraction.

Abstract:Extracting soil nutrient information using spectral analysis technology is very important for precision crop management. Difference indices (DIs), normalized indices (NIs) and ratio indices (RIs) were calculated from all available combinations with reflectance of two random bands between 1 000 and 2 500 nm, and correlated to soil organic matter (SOM), total nitrogen (TN) and available nitrogen (AN) content using dried soil samples from five different soil types in central and eastern China, then key spectral index and quantitative models for estimating SOM, TN and AN content were developed. Results show that spectral indices composed of reflectance corrected with multiplicative scatter correction (MSC) and collated with Savitzky-Golay (SG) smoothing method were highly correlated with the three soil nutrient indices. The sensitive wavebands well correlated simultaneously with the three nutrient indices were 1 879~1 890 and 2 050~2 100 nm, and DI(CR_{1 881}, CR_{2 070}) composed of the reflectance in wavebands 1 881 nm and 2 070 nm corrected with MSC and SG smoothing methods performed the best. Testing of the estimating models based on DI(CR_{1 881}, CR_{2 070}) with independent datasets from different types of soil samples resulted in validation of R², RMSE and RPD being 0.83, 0.79 and 0.72, 0.20 g kg^-1, 4.71 g kg^-1 and 23.96 mg kg^-1 and 2.56, 2.30 and 2.93 for TN, OM and AN, respectively, which indicates that DI(CR_{1 881}, CR_{2 070}) might be a good spectral index for estimating contents of the three nutrients simultaneously.

Abstract:Effects of burning biomass (rice straw) in the field on content and composition of soil organic matter were studied to explore changes in content and structure of humic acid (HA), fulvic acid (FA) and dissolved organic matter (DOM) in relation to frequency of burning. It was found that change in soil organic carbon occurred only within a few millimeters of surface soil layer. It decreased in content and the magnitude of the drop increased with frequency of burning, while soluble organic matter and its components increased in content. Humic substances from different sources responded differently to burning. The humic substances in three studied soils didn’t show any consistent variation trend with frequency burning, but HA and FA contents, HA/FA and E4/E6 increased or decreased regularly with increasing frequency of burning. The change in FA content was the leading factor affecting HA/FA ratio. Besides, from the FTIR, it was learnt that in FA aromatic fractions and Aliphatic substances, like C—OH, C—O, increased as frequency of burning increasing, while changes in HA were not noticeable because the aromatic condensation of HA per se is high.

Abstract:Distribution of soil organic carbon (SOC) and its affecting factors in four different types of natural grasslands (forest steppe, typical grassland, alpine meadow steppe and desert steppe) in the Loess Plateau were analyzed. Results show that content of soil organic carbon decreases with soil depth, and is significantly higher in 0~20 cm than in 20~40 cm, 40~60 cm, 60~80 cm and 80~100 cm. In the 0~40 cm soil layer, the distribution of organic carbon content in the four types of grasslands tends to be in the order of Alpine meadow steppe > typical grassland > forest steppe > desert steppe; while in the 40~100 cm soil layer, in the order of Alpine meadow steppe > forest steppe > typical grassland > desert steppe. In the Alpine meadow steppe, forest steppe and typical steppe of the Loess Plateau, soil organic carbon is concentrated in the surface layer (0~40 cm), accounting for 71%, 50% and 46% of the total in the profile (0~100 cm), while the distribution is more uniform in the desert steppe; Soil organic carbon content is positively related (p<0.01) to altitude; in the 0~40 cm soil layer, to soil water content (p<0.01); and to total nitrogen (r=0.984 3)；but negatively related to annual mean temperature (p<0.01). Moreover, it has no obvious relationship with annual precipitation in the 100 cm soil layer in all the four types of grasslands.

Abstract:An incubation experiment was conducted to study the distribution of ¹⁵N in mineral nitrogen, microbial biomass nitrogen and soil different size fractions after ¹⁵N labeled rice straw was added into the wushan and huangni soil. Gross nitrogen mineralization rates of rice straw in the two soils were also measured using ¹⁵N isotopic pool dilution technique. Results showed that soil mineral nitrogen decreased between 7 days and 28 days after straw was added into soils. Microbial biomass nitrogen increased before 7 days and changed less after 7 days. Mineral ¹⁵N was the highest at 7 days and accounted for 9.24%~12.3% of added straw ¹⁵N. Microbial biomass ¹⁵N was the highest at 14 days and accounted for 21.3%~40.5% of added straw ¹⁵N. Mineral ¹⁵N and microbial biomass ¹⁵N decreased between 7 days and 28 days after straw addition, which suggested that straw nitrogen was possibly lost at this time. At 56 days after straw addition, 10.5%~13.3% of added straw ¹⁵N existed in soil 53 ?m~2 mm fraction, 24.5%~26.5% was in soil 2~53 ?m fraction, and 30% was in < 2 ?m fraction. 5.7%~14.9% of added straw ¹⁵N was lost at 56 days. Straw decomposed more rapidly in the wushan soil than that in the huangni soil, and more straw ¹⁵N was lost in the wushan soil. Gross nitrogen mineralization rates of rice straw in the wushan and huangni soils were 1.61 and 1.48 mg kg^-1 d^-1 at 0.5 days and were 0.26 and 0.36 mg kg^-1 d^-1 at 56 d after straw addition, respectively.

Abstract:Ammonia (NH3) volatilization is a major pathway for gaseous nitrogen loss from fields applied with manure. To explore effects of topdressing of bio-digested manure slurry on ammonia volatilization, a field experiment was carried out in a vegetable greenhouse, applying bio-digested pig manure slurry (DPS) on winter vegetable, cress (Oenanthe clecumbens L.) and crown daisy (Raphanus sativus L. Var. Radiculus pers.), and summer vegetable, pak choi (Brassica chinensis L.) and chrysanthemum (Chrysanthemum carinatum Schousb.). The topdressing rates of nitrogen were 72 kg hm^-2, 54 kg hm^-2, 42 kg hm^-2 and 63 kg hm^-2, respectively, during the growing periods of vegetables. Results showed that (1) topdressing of DPS led to explosion of ammonia volatilization within 48 h; (2) the accumulative ammonia release of the growing season reached 8.68 kg hm^-2 and 9.90 kg hm^-2 in cress and radish fields, respectively, which were significantly higher than those in the plots topdressing with chemical fertilizer (CF) (4.06 kg hm^-2 and 5.59 kg hm^-2); however, in the pak choi and crown daisy fields, the value was 10.40 kg hm^-2 and 11.61 kg hm^-2, respectively, which were not so significantly higher than those in the plots topdressing with CF (9.81 kg hm^-2 and 10.09 kg hm^-2); (3) ammonia volatilization contributed 11.7% and 17.7% to the total N loss, respectively in the cress and radish plots topdressing with DPS in winter, and 23.3% and 26.8% in the pak choi and crown daisy plots in summer. The former was significantly lower than the latter; (4) temperature, water content, content of soluble organic carbon, form and concentration of nitrogen, biomass and activity of microbes in the surface soil at 0～10 cm depth were found to be the main contributors to ammonia volatilization. Application of bio-digested manure slurry in the vegetable field increased nitrogen loss through ammonia volatilization from DPS per se and its stimulative effect on decomposition of soil organic nitrogen. It is, therefore, essential to pay adequate attention to effects of temperature and application method in using bio-digested manure slurry as a soil amendment.

Abstract:Stationary observation was performed during the period from October, 2006 to October, 2007 of N₂O emissions from a field under wheat-maize rotation and a field under vegetable cultivation for over 20 years, using the static chamber method/gas chromatograph technique. Characteristics of the emissions from the two ecosystems were analyzed for differences between the two and effects of the participating factors, such as N application, soil temperature, soil moisture and crops on the emissions. Results show that in CK (No N applied) the mean N₂O emission flux was 17.8?5.6 and 50.7?13.3 ?g m^-2 h^-1, respectively, from the wheat-maize ecosystem and the vegetable ecosystem. Clearly the flux from the latter was 3.1 times higher than that from the former. When N was applied at N150 kg hm^-2, the N₂O emission coefficient in the vegetable field was 39.0% higher than that in wheat-maize field. Plant participation was not responsible for higher N₂O emission from the vegetable ecosystem. The difference in N₂O emission flux between the two ecosystems in different crop growing seasons was attributed to the fact that the difference in life cycle between the crops led to difference in intensity of N application per unit time. Therefore, N₂O emission from the agro-ecosystems may be cut down by regulating N application rate in light of characteristics of the crop growing season, which vary sharply especially of vegetables. If precise fertilization can be adopted for vegetables, the potential of the vegetable field in reducing N₂O emission would be greater than that of the upland farm field.

Abstract:A greenhouse pot experiment was carried out to study effects of a kind of bioorganic fertilizer (BOF) prepared out of fermentation of organic manure using as a starter strain XZ-173 lipopeptide-producing bacteria that are obviously effective in inhibiting the pathogen causing tomato bacterial wilt (TBW). Results show that the BOF effectively reduced the incidence of TBW with a relative control efficiency being 56.8%. Compared with treatments using chemical fertilizers or organic manure without using XZ-173 as starter, Treatment BOF significantly increased chlorophyll content of tomato leaves, biomasses of roots and shoots, and counts of bacteria and actinomycetes in rhizosphere soil, but reduced population of rhizospheric fungi. These beneficial effects of the BOF give it a broad prospect for application in cropping.

Abstract:Through long-term stationary field and plot experiments, effects of vegetable type and fertilization structure on nutrient loss with runoff were studied. Results show that nitrogen was the main nutrient element lost from vegetable field with runoff, and followed by potassium and phosphorus. NPK leaching was significantly higher in hot pepper field than in pumpkin field, because the former received a higher rate of fertilizer. P and K leaching was obviously higher in Chinese cabbage field than in cabbage field. NPK leaching from vegetable fields was higher in spring and summer than in fall and winter. At the early growth stage of eggplant, N and P leaching was more serious in CK₂ (local custom fertilization treatment) than in any other treatments. K leaching was higher in Treatment NPK (chemical fertilization) than in any other treatments. In the water samples from the first and second runoffs from Chinese cabbage and cabbage fields, N, P, K contents were higher in CK₂ and Treatment NPK than in any other treatments. At the later growth stage of vegetables, NPK leaching was higher in Treatment OM (organic manure) than in any other treatments and remained high. In Treatment CK₁ (No fertilization), nutrient loss still existed and was quite high, too. It is, therefore, recommended that the management of soil nutrient resources should be intensified to make efficient use of them in the production.

Abstract:In order to study responses of direct-seeding rapeseed to fertilization in fields of red soil different in fertility, and to find out limiting factors of direct-seeding rapeseed in nutrition, eight field experiments on crop response to NPKB fertilizers were conducted in typical red soil regions of Jiangxi and Hunan provinces in 2009－2010. Results show that growth of the direct-seeding rapeseed was significantly affected by soil fertilit. The yield of the field with basic soil fertility being high, middle and low was 1 230, 721 and 191 kg hm^-2, respectively. Fertilization promoted growth and nutrient uptake of the crop, increased its seed yield and influenced its harvest index to a varying degree. In all the experiment fields, Treatments NPKB were the highest in yield at each soil fertility level, The average yield of the treatments was 2 529 kg hm^-2 in fields high in soil fertility, 1 681 kg hm^-2 in fields moderate in soil fertility and 1 065 kg hm^-2 in fields low in soil fertility. Obviously yield of the crop increased with the soil fertility level by a large margin, but the margin tended to be narrower with the yield going up. The yield-increasing effect of additional fertilizer besides the combined recommendation followed the order of N ＞ P ＞ B ＞ K, which also indicated the order of importance of the four elements as limiting factor in nutrition of the crops. However, as affected by different in soil nutrient status, crop response to fertilization in fields different in soil fertility also varied. Relative yield response to fertilization was higher in fields low in soil fertility, while absolute yield and benefit responses were still better in fields high in soil fertility. N, P and K recovery rate of the direct-seeding rapeseed in the red soils was 34.5%, 26.7% and 65.4%, respectively, which increased with the soil fertility level. These findings demonstrate that in nutrient management of direct-seeding rapeseed, it is essential to pay high attention to combined application of N, P, K and B and elimination of nutrient limiting factors, to achieve effective yield increase. Long-term rational fertilization can build up the soil, improve soil fertility and hence sustain high and stable yield of the crops.

Abstract:In agricultural soils, besides anthropogenic sources, diazotrophs are the main source of nitrogen. Effects of temporary climate disturbance and cropping of maize on composition and diversity of nitrogen fixing bacteria in Pachic Udic Argiboroll and Fluventic Ustochrept were examined with the technique of nifH-gene targeted polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) approach combined with advanced statistical analysis, based on soil reciprocal transplantation experiments which were set up along a latitude gradient with distinctly different temperature and precipitation. Both cluster analysis and canonical correspondence analysis (CCA) show that soil properties could be the dominant factor to stimulate variation of diazotrophic composition, whereas temporary climate disturbances also caused a certain extent of differences. Contents of organic carbon and alkali-hydrolyzable N were found to be in significantly positive correlation with Shannon and Simpson indices while pH was in significantly negative correlation. Statistical analysis show that the content of alkali-hydrolyzable N was the determinant variable which explained the differences in diazotrophic composition among all samples (p=0.002). Hydrothermal conditions didn’t have any linear correlation with diazotrophic biodiversity. However, Pachic Udic Argiboroll showed the highest diazotrophic biodiversity while Fluventic Ustochrept showed the lowest under warm temperate climate. In addition, maize plantation increased slightly the diversity of nitrogen-fixing bacterial in all soils, except for in Chao soil in Hailun.

Abstract:Changes in soil microbial biomass carbon and enzyme activity in fluvo-aquic soil of the North China Plain were investigated after the soil, with or without cellulose, was amended with inorganic nitrogen and glucose in the experiment of incubation under constant temperature and humidity. The experiment was designed to have 8 treatments, i.e. control (CK), addition of inorganic nitrogen (N), addition of glucose (G), addition of cellulose (C), addition of glucose and inorganic nitrogen (C+N), addition of inorganic nitrogen in soil with cellulose (C+N), addition of glucose treatment in soil with cellulose (C+G), and addition of glucose and inorganic nitrogen in soil with cellulose (C+G+N). Cumulative soil carbon dioxide release, microbial biomass carbon and activities of dehydrogenase, β-glucosidase, catalase, and alkaline phosphatase were measured, separately at various intervals during the 33 days of incubation. Results show that in all microbial parameters no significant difference existed between CK and Treatment C. As against Treatments CK and C, all the treatments displayed a significant increase in cumulative carbon dioxide release, with Treatment C+G+N listed on the topmost. Treatments G, G+N, C+G, and C+G+N all showed an obvious increment in Cmic content and DHD, APH activity, particularly during the first two weeks of the incubation, while Treatments N and C+N displayed similarly like CK result. The findings implied that glucose could significantly increase microbial activity, but inorganic nitrogen could not. The effects of glucose and inorganic nitrogen on GLU and CAT were not obvious and in most cases no significant difference was found between different treatments. Correlation analysis demonstrates that carbon dioxide release rate was always positively related to APH activity, but not to Cmic and other enzymes activities and their relationships varied with the time of incubation, which was probably due to variation of the composition of soil microbial community or the way soil microbs utilize the substrates with the time of incubation. Cluster analysis further indicates that the 8 treatments could be sorted into three groups according to their soil microbial activity. Treatment C+G+N was the only one in the group of the highest activity, which suggests that it is important to amend the soil containing hard-to-decompose cellulose with inorganic nitrogen and readily available organic carbon at the same time for improving its soil microbial activity.

Abstract:Ginger cropping could regulate composition of soil microbial community, but its previous cropping might alleviate or aggregate the effect. To understand the effects of ginger cropping on soil microbial community as affected by its preceding cropping, variations of soil bacterial diversity were studied by analyzing PCR-DGGE fingerprints and DNA sequence in purple soil area of the Minjiang River. Four typical cropping modes (interplanting of corn + sweet potato, mono-cropping of soybean, continuous cropping of ginger, and rice-milk vetch rotation cropping) in this region were selected for the study. PCR-DGGE fingerprints clearly show that cultivation of ginger caused changes in number, position and brightness of DGGE bands, regardless of cropping background of the soil, e.g. reducing richness and Shannon-Wiener index of soil bacteria, and altering structure of the bacterial community. Among the four cropping patterns, the effects were the most significant in the one of continuous cropping of ginger, and the least in the one of interplanting of corn and sweet potato. However, cultivation of gingers made the soils under four different cropping patterns tend to be similar in structure of bacterial community. Sequencing of DGGE bands demonstrates that cultivation of ginger brought about disappearance of Chloroflexi group, and Nitrospira group as well, except for in the soil under the pattern of intercropping of rice-milk vetch, and appearance of bacteria of Brevundimonas in the soil under the pattern of interplanting of corn+sweet potato. The findings help understand the effects of ginger cultivation on soil environment, and provide some scientific basis for optimizing the mode of ginger cultivation.

Abstract:Soil microorganisms are a driving force in material recycling and nutrient transformation in soil. However, for a long time, soil has been treated as a “black box” system, wherein microbial diversity and biochemical processes they participate in soil remain to be explored. Since most of the soil microorganisms are still quite hard to be isolated for culture, traditional culture methods are quite limited in helping reveal compositions and functions of soil microbial communities. The metagenomic method is able to explore the structures and functions (sequence-driven approach) of soil microbial community and to screen bioactive materials and new genes (function-driven approach) through extracting all microbial DNAs direct from environment samples and then sequencing or constructing clone library, thus breaking through the bottleneck of the traditional methods and greatly enriching the knowledge about soil microbial biodiversity and functions. While reviewing main procedures of the metagenomic technique, the paper focuses on the introduction to application of the next-generation sequencing (NGS) technologies in metagenomic research and processing of the huge volume of data it may produce. The new processes on soil microbial ecology with the metagenomic technique is then discussed. And in the end, the authors propose that research projects on soil metagenomics projects should be launched at the national level to explore soil microorganism communities and their variation, so as to contribute to the causes of bioresource exploitation, agricultural production and environment protection.

Abstract:Volatile chlorinated hydrocarbons (VCHs) are common pollutants in industrial polluted sites, existing in aqueous phase, gaseous phase, solid phase or the form of dense non-aqueous phase liquids (DNAPL), in unsaturated zones of the soil, forming a dynamic equilibrium system. The sorption of VCHs by the soil not only influences concentration of the pollutants in the soil, but also affects substantially migration and fate of VCHs. Understanding the mechanisms of VCHs sorption by the soil may help predict their concentrations in the soil, optimize the parameters of pertinent models, and guide remediation and management of the contaminated soil. A review is presented to summarize characteristics of the distribution of VCHs between these phases in soils of unsaturated zones, their sorption mechanisms as well as their affecting factors, and to elaborate in particular influences of soil organic carbon, minerals, and soil water on their sorption. Meanwhile, existent problems are pointed out in the current researches and an outlook is described of the future researches.

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