Abstract:Quantitative assesment and comparison of comprehensive benefit of soil and water conservation in 3 small-scale watersheds varied in erosion management, i.e. Tangbei watershed, Liaogongkeng watershed and Jiaoxi watershed in Xingguo County of Jiangxi Province, were conducted, using an evaluating system of 30 evaluation indexes, including ecological, economic and social benefits. Results show that (1) evaluation using the established evaluating system and the applied method can well reflect the comprehensive benefit of soil and water conservation, and show certain regional applicability; (2) evaluation of a number of watersheds in the same region facilitates disclosing differences between watersheds in the benefit of water and soil conservation and their causes, which is of certain important practical significance in guiding control of soil and water loss in future; and (3) soil and water conservation of the 3 watersheds all yielded remarkable ecological, economical and social benefits, but did vary slightly due to the differences in the input and time of management, showing Tangbei watershed being the highest in ecological, economic, social and comprehensive benefits; Liaogongkeng moderately managed and the lowest in ecological and social benefit; and Jiaoxi watershed, poorly managed and the lowest in economic benefit. It is recommended that the watersheds should focus on their own respective problems in soil and water conservation and adopt pinpointing measures to further improve their soil and water conservation.

Abstract:Soil salinization is getting more and more attention the world over for its adverse impact on the social economy, the environment, and the agricultural eco-system. The total area of salinized soil in Xinjiang reaches 8.476×10⁶hm², accounting for 31.1% of the total cultivated land. It is, therefore, necessary and important to study soil salinization in arid regions for solution to this problem. Remote sensing (RS) technology demonstrates a number of advantages in this field. But how to extract salinization information accurately from RS images is the basis of the study. In this paper a case study of Yutian County monitoring soil salinization by means of remote sensing, is carried out. Yutian County was selected for this study because of its importance as a significant site for agricultural development. Located in the south of the Keriya oasis, it has recently been exposed to severe soil salinization. Seven-spectrum-band Enhanced Thematic Mapper-plus (ETM+) images dated October 7, 2002 were used against the data of soil features obtained from field investigation and analysis of typical soil information, to extract Salinization Index (SI) and land surface albedo, which are very important biophysical parameters of land surface. In this paper the relationship between salinization index (SI) and albedo was analyzed quantitatively. Through experiment and theoretical reasoning, the authors proposed a conception of SI-Albedo space and discussed its biophysical characteristics. Analysis revealed that location could be used to improve the current strategies for salinization in the SI-Albedo space, and hence the strategies for salinization mapping, by defining measurements in this feature space. Therefore, the authors present a methodology to monitor severity of salinization. Field data, available data in the literature, and ancillary data were linked with land cover characteristics (salinization index, land surface albedo) derived from Landsat ETM+ multispectral images. An information extraction model, using the decision tree classification method, was established and applied to classification of RS images. Results indicate that the classification based on SI-Albedo space has a higher classification accuracy than the one based on maximum likelihood. Its highest overall accuracy is about 0.92% higher than the maximum likelihood. Although both techniques show some mix-class phenomena in the classification result, but the classification based on SI-Albedo space has less than the maximum likelihood, and thus a higher separability. Salinity soil distribution maps show that the soil salinization of this study area is relatively severe and varying in degree and type; The area is dominated with light salinization and moderate salinization. The former is distributed mainly in farmland, while the latter around the Bostan swamp. And based on the salinized soil map, the salinity soil early-warning line was derived for anticipating further soil degradation. Such contrasting and complementary behavior suggests a potential synergism between salinization index and land surface albedo for mapping and monitoring of a complex soil salinization environment such as Keriya oasis.

Abstract:Historically, soil quality and function used to be assessed through routine soil chemical and physical analysis in the lab. Standard procedures for measuring soil properties are rather complex, costly and time-consuming. A rapid economical soil analytical technique is needed as there is a great demand for larger amounts of good quality, inexpensive soil data available for use in environmental monitoring, modeling and precision agriculture. In this paper possibility of predicting soil organic matter (SOM) content from measured reflectance spectra is studied using multiple linear stepwise regression (MLSR) and artificial neural network (ANN). After preprocessing of the primitive spectrum, some hyperspectral models for predicting SOM are built up with the aid of MLSR and ANN, and verified by a validation set. Performance of these two adaptive methods is compared in order to examine linear and non-linear relationship between soil reflectance and SOM content. Results show that to a certainty, both methods have some potential for application in estimating SOM. Performance indexes from both methods suggest ANN models are better than regression models, and the BP integrated model is better than the single BP model. Integrating the ANN subnets is a valid method for improving accuracy and stability of SOM retrieval. The ANN integrated model with the root mean square error (RMSE) of 1.31 is the best model in this research, which can be used in rapid acquisition of SOM content.

Abstract:Particulate organic matter (POM) structures of both bulk soil and size fractions of water-stable aggregates from a typical hydroagric paddy soil from Tai Lake region, Jiangsu Province, and a red earth-derived paddy soil in Jiangxi Province, China under long-term different fertilization trials were studied by CPMAS¹³C-NMR spectroscopy. Little variation was found of the composition of C species with size fractions, with the soil types and with the fertilization treatments as POM in both bulk soil and water-stable aggregates. Both soils were composed basically of O-alkyl-C, Alkyl-C and Aromatic-C, with the former being dominating. However, different fertilization treatments modified the proportion of different carbon species of the POM from the bulk samples as the portion of O-alkyl-C was decreased and that of aromatic-C and phenolic-C increased under both organic fertilization and compound fertilization of organic and inorganic fertilizers, indicating the enhanced chemical stability of POM under organic amendments; Whereas, increased portion of O-alkyl-C but decreased portion of alkyl-C, aromatic-C and aromaticity was observed under chemical fertilization only, indicating a more readily decomposable nature. The relative proportion of each C species also differed in water-stable aggregates of the size fractions from both soils and long-term different fertilization treatments, and it modified the interactive effect of POM and water-stable aggregates of the paddy soils, which is less significant for the red earth-derived paddy soil.

Abstract:The BIOLOG method was applied to exploration of functional diversity of soil microbial communities in sludge-amended soils sampled from the Yangtze River Delta．Results indicated that metabolic profile, functional diversity indexes and kinetic parameters of the soil microbial communities changed following soil amendment with sewage sludge, suggesting that the changes occurred in population of the microbes capable of exploiting carbon substrates and in this capability as well. The kinetic study of the functional diversity revealed that the metabolic profile of the soil microbial communities exhibited non-linear correlation with the incubation time, showing a curse of sigmoid that fits the dynamic model of growth of the soil microbial communities. In all the treatments, except for treatments of coastal fluvo-aquic soil amended with fresh sludge and dried sludge from Hangzhou, kinetic parameters K and r of the functional diversity of the soil microbial communities decreased significantly and parameter S increased. Changes in characteristics of the functional diversity well reflected differences in C utilizing capacity and model of the soil microbial communities in the sludge-amended soils, and changes in functional diversity of the soil microbial communities in a particular eco-environment, like soil amended with sewage sludge.

Abstract:Based on the long-term experiment in Taoyuan Agroecosystem Experimental Station of Chinese Academy of Sciences, this paper studied effects of long-term quantitative fertilization on accumulation and availability of Cd, Pb, Cu and Zn in the red paddy ecosystem. The application of chemical fertilizers decreased the concentration of Cd in soil, and Cd uptake by rice might be the main reason for this. When recycling of organic matter brought some nutrient elements back into the soil, Cd was among them. The effect of the recycling changing soil properties and hence soil Cd played a more important role than the effect of Cd uptake by rice in accumulation of Cd in the soil. Both application of chemical fertilizers and recycling of organic matter increased Pb in the red paddy soil, but did not have any significant effect on Cu and Zn. Long-term application of chemical fertilizers had little effect on Cd, Pb, Cu and Zn, while recycling of organic matter improved availabilities of Cd and Zn significantly. The increase in soil organic matter and the decrease in soil pH caused by recycling of organic matter might be the main reason for the promotion of availabilities of Cd and Zn.

Abstract:A 75-day-long pot experiment was carried out to study effect of plantation of ryegrass (Lolium multiflorum) on dynamic degradation of phenanthrene (PHE) in soil. Results indicate that ryegrass plantation enhanced degradation of PHE in the soil, thus making the content of extractable PHE lower (p<0.05) in the ryegrass pots than in CK (pots without ryegrass). In the treatments, 5, 50, and 200 mg kg^-1 in PHE concentration, PHE degradation rate reached 81.07%, 90.35% and 84.94%, respectively, while in CK it was only 73.5%, 86.2% and 67.60%, respectively. Ryegrass plantation enhanced activities of polyphenol oxidase, dehydrogenase and catalase, and increased content of microbiological biomass C, that is, the soil biological activity, thus raising the degradation rate of PHE in the soil. And soil biological activity varied sharply from treatment to treatment. Higher concentration of PHE inhibited soil biological activity, and in turn the effect of soil biology on PHE degradation. Thus, the findings disclose the biological and enzymological mechanisms of the plant enhancing PHE degradation. And it was also found that ryegrass is rather tolerant to polycyclic aromatic hydrocarbons, but higher PHE concentration affected ryegrass growth.

Abstract:A greenhouse experiment was conducted by using a specially designed rhizobox where ryegrass (Lolium perenne L.) seedlings were grown for 60 days in a soil treated with pyrene at a rate of 100 mg kg^-1 soil to investigate rhizosphere effects on degradation of pyrene in the soil. The soil in the rhizobox was divided into several compartments separated with nylon mesh. Soil samples were collected in the root compartment (S0), and other compartments 0~2mm (S1), 2~4mm (S2), 4~6mm (S3), and >6mm (S4) for determination of extractable pyrene concentrations, soil microbial biomass C, soil basal respiration rate, microbial biomass C/organic C, and metabolic quotient, dehydrogenase activity and polyphenol oxidase activity. Results show that significant differences were observed between the compartments in extractable pyrene concentrations in treatments with ryegrass and they followed the order: S4 >S3 >S0 > S2> S1. However, an opposite trend in variation was found with soil microbial biomass C, soil basal respiration rate, microbial biomass C/organic C, and metabolic quotient, dehydrogenase activity and polyphenol oxidase activity. Between treatments without ryegrass, no difference was detected in extractable pyrene concentration, soil microbial biomass C, soil basal respiration rate, microbial biomass C/organic C, and metabolic quotient, dehydrogenase activity and polyphenol oxidase activity. Negative correlations were significant (p <0.05) between the extractable pyrene concentrations and the other six indexes in various sampling zones of soils with growth of ryegrass plants. Results of the principal components analysis show that soil microbial activities changed sharply in all the compartments of the treatments with ryegrass.

Abstract:PCB contamination levels of farmland soil and vegetables in the surroundings of E-waste contaminated areas were investigated and the risks to human health in these areas were assessed. The investigation findings show that the average PCB concentrations in soil and vegetables were 6.78~15.48 μg kg^-1 and 5.98~130.70 μg kg^-1 respectively. Compared with the background level of Tibet, West China, and the PCB contamination level in the rural farmland of Zhejiang Province, there exists high accumulations of PCBs in the farmland surrounding E-waste areas. The health risk assessment based on the comparative analysis of soil and vegetables pollution resulting from the exposure to food chain indicates that cancer risk in one’s lifetime is 6.50×10^-6~1.24×10^-4, which is one to three order of magnitude higher than the standard concentration level. It is suggested from vegetable samples that the non-carcinogenic risk level for some farmlands is higher than the acceptable level (HQ=1). It is concluded that in the stated area PCB concentration in the farmland ecological system has posed a major risk to human health.

Abstract:To bring ecological functions of upland red soil into full play and screen out better maize cropping systems, a study was carried out making full use of the data accumulated in the recent 23 years of field experiments and analyzing production, energy flow, value flow and integrated utilization/cultivation functions of 15 different maize cropping systems in the soil. Comprehensive evaluation of the cropping systems was performed on the basis of 13 indexes of ecological benefit, economic benefit and social benefit by means of Grey relation degree. Three maize cropping systems were screened out to be optimal and fit for extension on upland red soil. Results shows that the grey relation degree of the ecological benefit and social benefit of Treatment X (pea/early maize + upland rice/late maize) reached 0.750 and 0.986, respectively, ranking first among the 15 and of economic benefit got to 0.841, ranking second. And the treatment was the highest in weighed grey relation degree and hence assumed to be the priority system for extension in the red soil regions in South China. Treatment XI (pea/cotton + early maize) and Treatment XII (Chinese milk vetch—early maize—sesame) followed, being 0.739 and 0.716 in weighed grey relation degree, and would have important roles in optimizing the cropping systems in the upland red soil.

Abstract:A hydroponic experiment was carried out to investigate the effect of light intensity and NO₃^--N/NH₄⁺-N ratios on the content of total carbon and total nitrogen in different organs, root activity and nitrate absorption of Pakchoi. Results show that: ⑴when there was no ammonium in the nutrient solution, low light intensity (50% of nature light) decreased dry weight of the leaf, petiole and root by 73.8%, 82.2% and 74.4%; total carbon by 76.7%, 84.5% and 79.4%, and total nitrogen by 71.2%,79.5% and 80.4% respectively⑵low light intensity also decreased root activity and nitrate absorption of the plant significantly and ⑶under low light intensity, dry weight, total carbon, total nitrogen and root activity of the plant peaked when nitrate/ammonium ratio was 85 : 15 in the solution, and nitrate absorption by the plant decreased with increasing ammonium supply.

Abstract:With the aid of the Free-Air Carbon Dioxide Enrichment (FACE) system and the isotope ¹³C technique, effects of elevated atmospheric p CO₂ and nitrogen fertilization on replacement rate of soil organic carbon (SOC) in wheat field, through planting wheat (Triticum aestivum L. cv Yangmai 14) under a rice/wheat rotation system in a C₄ soil, on which only maize had been planted for years. Results show that after one crop of wheat, the value of δ ¹³C in SOC fell significantly, suggesting that wheat growth had altered the composition of SOC, and that elevated atmospheric p CO₂ stimulated the crop to transfer more organic carbon into the soil, thus increasing the SOC replacement rate in the wheat field from 3.61% to 6.72% when the nitrogen application rate was 150 kg hm^-2, LN and from 4.59% to 8.55%, when the application rate was 250 kg hm^-2, HN, or by 72.7% and 86.1%, respectively. It is quite obvious that elevated atmospheric p CO₂ and higher nitrogen application rate will accelerate SOC replacement in farmland soil.

Abstract:Soil samples were collected from protected fields in Yuhong District of Shenyang, Liaoning Province, China, for determination of exchangeable acid, exchangeable base and pH, and further analysis of acidification characteristics of the soils and relationships of soil pH with the other two. Results show 1) that soil acidification displayed a clear rising trend after the field began vegetable cultivation under protection. Soil exchangeable acid content in the protected fields were much higher than those in the control. Soil pH was determined mainly by exchangeable acid in potential acid. The proportion of exchangeable Al³⁺ increased with exchangeable acid，while decreased with increasing OM. And, the proportion of H⁺ in exchangeable acid showed a reverse trend2）Exchangeable bases, especially exchangeable Mg²⁺, K⁺ and Na⁺, in various layers of the soils in the protected fields were much higher than those in the control, not only in content, but also in saturation, whereas soil exchangeable Ca²⁺ did not vary much, but the base saturation and exchangeable Ca²⁺ saturation decreased significantly3）Soil pH was in significant negative correlation with exchangeable acid and nonexchangeable acid，but in significant positive correlation with base saturation, which is mainly restrained by dominant exchangeable Ca²⁺.

Abstract:A successional Artemisia ordosica and A. frigid community, located on the eastern edge of the Tengri Desert in Alashan Left Banner, Inner Mongolia, was selected as an object for study. Densities of the plants and total nitrogen (N) and available phosphorus (P) in 0~20cm soil layer were measured of the 400 quadrates (4m×4m) in the sampling plot (80m×80m) for analysis of relationship between N/P ratio in the soil and plant density thereupon and between the two in spatial heterogeneity. Results show that with increasing N/P ratio, the density of A. ordosica decreased, but the density of A. frigid increased; while with intensifying spatial heterogeneity of N/P ratio, the spatial heterogeneity of A. ordosica density weakened but the spatial heterogeneity of A. frigid density displayed no relationship, which suggests that the plant density is closely related to N/P ratio, and A. frigid is displacing A. ordosica as N/P ratio increases. Thus, change in N/P ratio in the soil is one of the causes of the succession of A. ordosica community in the arid zone.

Abstract:Adsorption, desorption and insecticidal activity of 65 kDa and 130 kDa proteins from Bacillus thuringiensis subsp. Kurstaki (Btk) on red soil colloids were studied. The proteins from Btk were easily adsorbed on red soil colloids and the adsorption reached equilibrium within 0.5 h The adsorption rate of 65 kDa protein was higher than that of 130 kDa protein The adsorption isotherms of the two proteins in Tris buffer (pH 8) followed the Langmuir equation (R² > 0.992) and more 65 kDa proteins adsorbed than 130 kDa proteins. The adsorption rates of the two proteins decreased slightly with the rising temperature from 10�C to 50�C, and declined, too, with the rising pH value from 6 to 8 (Tris buffer). Both free and adsorbed proteins were toxic to the larvae of Heliothis armigera, and the insecticidal activity of adsorbed proteins was 2~5 times higher than that of free proteins. Desorption experiments revealed that the proteins were tightly bound onto the clays, and only 37.2% and 22.9% of the proteins, 65 kDa and 130 kDa, respectively, adsorbed at equilibrium was desorbed after three washes with deionised water, 20.7% and 14.8% was desorbed after three washes with Tris buffer (pH 8). Infrared absorption spectra showed that the proteins did not alter much in structure, either adsorbed or desorbed. The analysis using transmission electron microscopy (TEM) showed that no obvious changes was observed in particle size of soil colloids In red soil either before or after adsorption. Adsorbed Bt proteins were higher in insecticidal activity, but low in desorption rate, which means that release of proteins from transgenic Bt plants may pose a potential environmental risk.

Abstract:Effects of nitric acid treatment on content, cation exchange capacity, optic nature and adsorptive characteristics of extractable humic acid in Shanxi brown coal were studied with the ion-exchange equilibrium method. Results show that content of extractable humic acid increased by 45.8% by treatment with nitric acid of certain concentration, thus consequently bringing up its cation exchange capacity, But the two changes were not conincident, with the latter lagging behind the former. Besides, optic characteristics of the humid acid in the acidtreated brown coal were greatly changed too. Its adsorption capacity of NH₄⁺, and K⁺ was significantly increased by 58.73% and 41.53%, of which the isothermal adsorption equation fitted the Freundlich equation and Langmuir equation, respectively. However, contrarily, the adsorption capacity of P was significantly lowered. Its variation could well be described by the Langmuir equation. The changes in the physic-chemical properties of extractable humic acid in the brown coal make the coal fitter for application as slow-release fertilizer.

Abstract:A pot experiment was carried out to study effects of Cu stress on growth of Alternanthera philoxeroides, content of chlorophyll, biomass of the plant, and activity of four species of soil enzymes(Invertase, Catalase, Urease and Phosphatase). Results show that Cu pollution retarded growth of the plant, and reduced its average plant height, and contents of chlorophyll a and chlorophyll b. With increasing Cu content, activity of the soil enzymes decreased. The activity of the four species of soil enzymes was closely related to concentration of Cu, and hence could be used as indicator of the degree of Cu pollution in soil. In terms of sensitivity to Cu stress, the four species of soil enzymes were in the order of Invertase＞Catalase＞Urease＞Phosphatase.

Abstract:Soil structure is the physical framework where all the soil processes occur. Quantification of soil structure is fundamental to the research on water movement, gas exchange, heat transfer, soil fauna activity, and soil chemical processes. Contents of the research were discussed, and major methods applicable to the study and applications of the fractal theory, Boolean model, and pore network model were briefly introduced. Besides, outlook of the study was presented.

Abstract:The exposure of medicines to environment and its eco-hazards is a research focus in the world, and veterinary medicines used largely in animal food industry have become an important sources of the pharmaceuticals in environment. Most of veterinary medicines taken by animals are shown in their original forms or various metabolites in animal excrement. In this paper the residues, degradation and its affecting factors of veterinary medicines in animal excrement are reviewed, and the influence of the residual veterinary medicines on the compost process of animal excrement is also introduced.

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