Abstract:A water infiltration experiment，soil porosity and CaCO₃ content determination was conducted at Fengqi in Luochuan of Shaanxi Province on soil profiles of loess and palesol to explore infiltration characteristics and the conditions for groundwater enrichment Results show that stable infiltration rate of Horizon L₄, L₅, L₆and L₇of Loess profile in Xigou, Luochuan, was higher, averaging 0.65 mm min^-1 and the stable infiltration rate of Horizon S₄, S₅, S₆and S₇ was lower, averaging 0.37 mm min^-1. In the loess profile infiltration rate leveled off quickly, generally within 60~90 minutes, while in the palesol it did slower, usually within 90~120 minutes. With higher porosity and higher infiltration rate, the loess had a welldeveloped aquifer, which is attributed to the dynamics of cold-dry climate. Low in porosity and weak in permeability, paleosol tended to form an impermeable layer, which is attributed to the dynamics of warm and humid climate. Attempts were made to fit the three infiltration equations with the data obtained from the infiltration experiment. The three empirical formula commonly used are all applicable to describe infiltration law of loess and paleosol 400 ka~700 ka BP old. The findings of the study have opened up a new field for application of the theory of climatic change in the Quaternary. It is quite clear that the information of climate change in the Pleistocene is of high application value in the study on conditions of enrichment of soil water groundwater and rules of the enrichment, and exploitation of the water resources.

Abstract:A total of 54 profiles of soils derived from various main purple strata were collected according to the nomenclature of purplish soil in Chongqing area for analysis of total titanium and amorphous titanium. Results show that total titanium (TiO₂) varied in the range of 2.70 g kg^-1to 23.9 g kg^-1 in content, averaging 7.52±3.90 g kg^-1. The content of soil total titanium was closely related to parent rock of the soil, while it was little affected by weathering degree of the soil, and its distribution did not have any set rule to follow Comparison in titanium value (ratio of total Ti/ amorphous Ti) between the soils at their initial weathering stage and their parent rocks showed little difference, following a decreasing order of Trias T₁f ＞ Jurassic J₃p ＞ Jurassic J_1—2z＞ Jurassic J₂s ＞ Jurassic J₃s ＞ Cretaceous K₂j Titanium value decreased remarkably with rising weathering degree and varied in coincidence with the description of weathering degree based on value of SiO₂/(Al₂O₃+Fe₂O₃). The correlation coefficient between the two reaches a significant level ( r = -0.809 1 * * ). If the titanium values are divided into seven grades, fromⅠ to Ⅶ, purplish soils different in weathering degree can be sorted into their respective grades. Thus grades of titanium value can be used to describe weathering degree of purplish soils.

Abstract:Distribution characteristics of elements in soil reflect the result of pedogenic process under the integrated impact of a number of natural and anthropogenic factors. In order to understand influences of human activities and natural processes on formation and evolution of Earth-cumuli-Orthic Anthrosols, two typical profiles of Earth-cumuli-Orthic Anthrosols were collected on the third terrace of the Weihe River in the central-west Loess Plateau for analysis of distribution characteristics of trace elements, including Cu, Zn, Pb, Rb, Sr. Results show that Cu, Zn, Pb, and Rb were relatively enriched in the buried paleo-surface horizon (2A) and paleo-argillic horizon (2Bt), where natural pedogenic eluviation and illuviation was playing a main role. Under the relatively warm and moist climate, Sr leaching was strong, showing entirely contrary distribution characteristics with obvious loss in the horizons of 2A and 2Bt. From the buried plow horizon(Aupb) to the subplow horizon(Aup₂) and the modern plow horizon(Aup₁), contents of Cu, Zn and Pb increased slowly. According to the calculated relative enrichment coefficient, only Zn in Aup₁ horizon of YL01 profile was obviously enriched with an enrichment coefficient higher than 1.1, showing that the influence of human activities on the contents of trace elements in Earth-cumuli-Orthic Anthrosols is generally quite weak.

Abstract:Virtual soils, rich in macropore, but different in level, were constructed with the aid of the Voronoi tesselation algorithm on two dimensional lattices and transport behaviors of solute particles therein numerically simulated using random walk models. It was found that the solute diffusion was anomalous and its mean square of displacement was positively correlated with time, being ＜r²(t)＞∝t^K. Values of K depended on the types of soils and the types of random walk models. With biased random walk models, the values increased with the time, which means the particles diffused faster with the time went on. The first passage time of solute transport satisfied the logarithmic normal distribution. Non-fick effect of the diffusion was obvious with the continuous time random walk theory. And it was found that soils different in por structure would have different corresponding fitting parameters with the random walk models, that is to say, they also affected the transport behaviors of solute particles. The findings of the study are found to be helpful to researchers in understanding and predicting behaviors of water and solutes in macroporous soil, and hence in helping protect the underground water environment.

Abstract:Drought is the major climate disaster affecting agricultural production in China. The drought, frequently occurring in winter/spring, especially in spring, often brings about serious adverse impact on winter wheat production. Using remote sensing technology to monitor drought during the winter wheat growing season is an important development trend in management of agricultural drought. Based on the 2005 EOS/MODIS data available from NASA, a study was conducted on complementarily of remote-sensing-databased drought monitoring models for different periods of spring in Hebei Province. Results show that (1) better complementarily existed between apparent thermal inertia (ATI) model and temperature vegetation drought index (TVDI) model during winter wheat’s growing period. ATI model should be used to monitor drought in March; (2) for estimation of relative soil moisture (RSM) in surface soil in April-May, both TVDI and ATI can be used for both RSM-TVDI fitted equation and RSM-ATI fitted equation passed the t-check (α＝0.001), showing better correlations. TVDI and ATI could be used to estimate surface soil moisture from April to May; and (3) based on correlation analysis and error analysis of equations of RSM-TVDI and RSM-ATI for April and May, ATI model is the best choice for early April, and TVDI model for mid-April. And for the period from late April to late May, the TVDI model is more suitable.

Abstract:One hundred and forty seven surface soil samples were collected from a contaminated site in Fuyang, Zhejiang Province for determination of concentrations of total copper, zinc, lead and cadmium in the soil. Spatial distribution of the four heavy metals in the study area was predicted using the combined prediction method (ordinary block kriging and triangular irregular network interpolation), and pollution probabilities, too, using the indicator kriging Once again based on their respective soil pollution thresholds (i.e. soil environmental quality standard), and pollution probability thresholds (i.e. 50%), pollution scopes of the heavy metals were defined separately. The two results were compared for integrated definition of scopes of their pollution. In light of the severity of the pollution, heavy metal pollution of the studied region was sorted into “Polluted”, “Unpolluted” and “Undefined”. Results of the integrated definition show that 71.7%, 80.0%, 3.0%, and 83.1% of the soils in the area were polluted by Cu, Zn, Pb and Cd, and 20.8%, 10.5%, 12.5% and 10.9% were undefined whether they were polluted by Cu, Zn, Pb and Cd or not, respectively.

Abstract:Composition and contents of chlorinated organic compounds were investigated of soils around used electronic device disassembling sites in the Yangtze River Delta. Results show that the total of the 20 kinds of PCBs in the test soil was in the range of 84.19～377.4 μg kg^-1, with an average va1ue of 204.8 μg kg^-1, of which subchloride PCBs include Di-Cl, Tri-Cl and Tetra-Cl accounted for 73.7% ~96.2% of the ∑PCBs, indicating input of exogenous PCBs. The total of HCH was in the range of 10.61～33.11 μg kg^-1, and the total of DDT in the range of 11.36～33.28 μg kg^-1, being quite low in residue level. Most of the HCH and DDT in the soils have degraded, but the average contents of β-HCH, γ-HCH, ∑HCH and ∑DDT were all higher than the corresponding target values in the Dutch List. Moreover, correlation analysis shows that residual contents of DDT in the soils was negatively related to total organic carbon (TOC) content, but such relationship was not found between TOC and other detectable organochlorines.

Abstract:A 115-day experiment of composting oily sludge with straw and organic manure was carried out. During the process, dynamics of total petroleum hydrocarbon (TPH) content, temperature, C/N/P ratio and population of functional microorganisms were monitored, and composition and biotoxicity of petroleum waste were analyzed before and after composting. Results show that TPH content decreased from 123±1 g kg^-1 to 71.7±0.7 g kg^-1, demonstrating a degradation rate of 42%, which was 2.5 times high than CK (without composting). The composting treatment reached the highest temperature, 50℃ on D21 and showed a decreasing C/N/P ratio. The counts of hydrocarbon degraders and aromatic hydrocarbon degraders in the composted sludge increased by about 2 orders of magnitudes compared with those in the uncomposted sludge. Moreover, EC50 in the oily sludge increased from 1.77±0.28 mg ml^-1 before composting to 2.76±0.38 mg ml^-1 after composting, indicating a decrease in biotoxicity of the sludge.

Abstract:Aluminum (Al) toxicity often exists in plants growing on acid soils, limiting crop production therein. Microscopic techniques are commonly used in the research on Al toxicity in plants. A comparison study was carried out of the advantages and disadvantages of three microscopic techniques, hematoxylin staining method, fluorescent staining method and electronic microscopic scanning method, using growing under Al stress. Results show that the hematoxylin staining method could distinguish difference in morphologic variation of root tips between two different cultivars of lespedezas and between different Al treatments. The fluorescent staining method could detect differences between plants in control and in Al treatments, and make it convenient to observe mucilage on root surface and Al distribution in apoplast. The electronic microscopic scanning method could make out differences between the plants in control and in Al treatments, but could not find out difference in Al tolerance between cultivars of lespedezas through energy spectrum analysis.

Abstract:Effect of forms of N fertilizers on Cu bioavailablity in a contaminated red soil was investigated. Results show that contents of watersoluble and available Cu varied with the forms of N fertilizer. At the first days of cultivation, the application of CO(NH₂)₂ significantly decreased the two fractions of soil Cu, while the addition of (NH₄)₂SO₄ and Ca(NO₃)₂ increased water-soluble Cu, and the effect of the latter was much higher than the former. But the two forms of N did not have as much effect on available Cu. After 60 days’ cultivation, the negative effect of CO(NH₂)₂ on the two fractions of Cu turned to be positive, and the positive effect of (NH₄) ₂SO₄ was further more enhanced. The positive effect of Ca(NO₃) ₂ on the two fractions of Cu was, however, less than that of CO(NH₂)₂. The two fractions of Cu also varied sharply with the application rates of nitrogen fertilizer. When N levels were kept the same, the effect of N fertilizer on both watersoluble and available Cu differed significantly, showing an order of (NH₄)₂SO₄ > CO(NH₂)₂> Ca(NO₃) ₂. The change in soil pH led to different effect of different N on Cu bioavailability. Significant negative correlation was observed between pH and two fractions of Cu.

Abstract:A pot experiment of maize was conducted from June 9 to September 25 in 2007, to explore variations and relationships between intercellular CO₂ concentration (C_i), stable carbon isotope discrimination (Δ¹³C) and CO₂ leakage from bundle sheath (φ) during photosynthesis of summer maize in six typical growth stages (seedling, jointing, booting, tasseling, filling, and mature) under different water regimes, using the stable carbon isotope technique and Portable Photosynthesis System (LI-6400, LI-COR, Inc, USA) The plants were subjected to four water regimes, i.e. 75%~100% (Treatment W1), 50%~75% (Treatment W2), 30%~50% (Treatment W3) and 0~30% (Treatment W4) of the field capacity of the soil. Results show that (1) stomas on the summer maize leaf closed under water stress at the jointing stage, which led to lower C_i in Treatments W2, W3 and W4, as compared with that in Treatment W1. At the following growth stages of booting, tasseling and filling, C_i in Treatments W1, W2 and W3 decreased with intensifying water stress; however, C_i in Treatment W4 was higher than in Treatments W2 and W3. Leaf aging sped up and C_i increased with intensifying water stress at the maturing stage; (2) under the joint effect of water regimes and growth stages, in Treatments W1, W2 and W3 Δ¹³C for summer maize leaves displayed a trend similar to that of C_i/C C_a from the jointing stage to the filling stage, but a different one at the maturing stage; whereas in Treatment W4 it did only from the booting stage to the filling stage; no matter in what treatments, Δ¹³C was significantly correlated with φ, which affected Δ¹³C more than C_i/ C_a did; and (3)φvaried in a trend similar to that of Δ¹³C in the maize leaf in all the treatments, however, in Treatments W1, W2 and W3 φ declined with intensifying water stress, while in Treatment W4 it turned upwards.

Abstract:Based on a 26-year-long fertilization experiment in paddy field, effects of fertilization on distribution, density and mineralization of organic carbon in soil profiles in paddy field were studied. Results show: 1) Long-term fertilization significantly increased organic carbon content in the top soil, and Treatments MR (application of organic manure plus return of crop straws) demonstrated a more contributive effect than Treatments CF (application of chemical fertilization alone) on organic carbon accumulation in the top soil. Organic carbon content in the 10~30 cm soil layers of Treatments CF and in the 20~40 cm soil layers of Treatments OM (organic manure) was relatively stable. 2) In the 0~25 cm and 0~50 cm soil layers, organic carbon density was found higher in Treatments OM than in Treatments CF, the highest in Treatments MNP and CNPK, and in Treatment CRN than in Treatment MRN. Compared with CK, Treatment C0 (no fertilization), all the other treatments varied more greatly in organic carbon in the 0~25 cm and 25~50 cm soil layers, Treatments OM did more than Treatments CF, and Treatments CNP and MNPK the most. 3) Organic carbon mineralization reached the peak in the first 2~4 days, and gradually leveled off in the 3 weeks that followed. The rate was higher in Treatments OM than in Treatments CF, with average mineralization rates varying in the range of CO₂ 55.36~75.46 ml kg^-1 d^-1 and stable mineralization rates in the range of CO₂ 10~20 ml kg^-1 d^-1. In the eight weeks of incubation, Treatments OM were always higher than Treatments CF in cumulative mineralization and Treatment MRN was the highest. The total mineralization intensity and stable mineralization rate remained stable in all the treatments.

Abstract:A research using the Denitrification-Decomposition (DNDC) model was carried out to study spatial-temporal variation of SOC storage at both field and county scales, based on the data of a long-term (12 a) fertilization experiment in paddy field and the comparison of two field surveys in 1998 and 2001 in Yujiang County. Results show that the model simulated well the variation of SOC in the long-term experiment. The total SOC storage in the surface layer (0~20 cm) of paddy field in Yujiang County was estimated at 2.9×10⁹ kg and the average SOC density was 6.0 kg m^-2 in 2001. The SOC storage in the surface layer increased annually on average by 3.0×10⁷ kg from 1998 to 2001. Scenario analysis of the period from 1998 to 2017 show that SOC storage could be effectively improved by planting green manure, increasing straw returning rate and reducing chemical fertilizer application rate.

Abstract:Formation, distribution and contributing rates of aggregates to organic carbon in black soil in a 28-year long-term fertilization experiment were explored with the physical fractionation method. Results show application of organic fertilizer promoted formation of large-sized aggregates (>0.25 mm), especially 2～1 mm fraction, while combined application of chemical and organic fertilizer did the formation of <1 mm fraction, particularly 0.5～0.25 mm fraction. Fertilization, no matter chemical or organic, increased organic carbon content in the soil, however, the effect of combined application of organic and chemical fertilizers was better than that of the application of either organic or chemical fertilizer. Distribution of organic carbon in aggregates formed two peaks, one in 2～1 mm fraction and the other in 0.25～0.053 mm fraction. In fertilization treatments, no matter organic, chemical and combined, the contribution of 0.5～0.25 mm fraction to organic carbon in the soil was greater than in CK, while application of organic fertilizer alone did more than CK the contribution of 1～0.5 mm fraction. However, in the case of the typical black soil in Northeast China, 2～1 mm and 0.25～0.053 mm fractions contributed the greatest to the protection of organic carbon in the soil, suggesting that the effect of aggregates protecting organic carbon in the soil is the result of the integration of distribution and mineralization of organic carbon. It is, therefore, feasible to effectively preserve soil qualify and fertility by choosing types of fertilizers.

Abstract:In order to understand effects of acid rain on nitrogen (N) balance of soil-vegetable systems, field experiments were carried out at three sites in Chongqing for one year to monitor N dynamics in soils and vegetables, atmospheric N deposition from rainfall, and N leaching loss. These sites were subjected to acid rain to a varying extent, i.e. heavily polluted area (HPA), lightly polluted area (LPA), and control area (CK). Under the condition of similar field management, acid rain affected normal growth of vegetables and hence N balance in the soil-vegetable systems at the three sites. The N I/O ratio (input/output) was 1.27 and 1.19 in HPA and LPA, respectively, while it was 1.08 (nearly reaching the balance) in CK. The N input from rainfall in HPA was about 3 to 4 times higher than that in LPA and CK. However, the biomass of vegetables in HPA was decreased by up to 40%, when compared with that in CK, thus leading to a significant decrease in N output through crop harvesting. As a result, a large proportion of N was sequestrated in the soils subjected to acid rain, which subsequently enhanced nitrate leaching posing a risk to water environment.

Abstract:Na-alginate was selected as an entrapping agent to immobilize ammonia-oxidizing bacteria in this experiment, designed to explore optimal entrapping condition and to compare immobilized bacteria with non-immobilized bacteria in ammonium removal efficiency. Results show that when Na-alginate was at 4%, and CaCl₂ at 3%, an optimal entrapping condition was achieved with bacteria entrapment reaching at 3.0 g L^-1, and ammonia removing rate at 80%. Compared with non-immobilized cells, the immobilized ones were more adaptable to variation of temperature and pH, as well as exposure to organic matter and toxicants.

Abstract:Effects of low molecular weight organic acids on phosphomonoesterase activity in red soil were investigated in lab. Results show that phosphomonoesterase activity was enhanced by organic acids in low concentration (< 1 μmol g^-1), and the effect followed the order of citric acid ≈ oxalic acid > malic acid > tartaric acid, but inhibited by organic acids in high concentration (> 5 μmol g^-1) and the effect followed the order of citric acid > oxalic acid > malic acid > tartaric acid. On the one hand, phosphomonoesterase activity was improved when pH of the system approached to the value, where enzymic reaction was optimal, while inhibited when the pH varied the other way. On the other hand, phosphomonoesterase activity was increased by organic acidic radical via carboxyl, while inhibited by release of metal ions.

Abstract:Improving the culturability of soil microorganisms and isolating pure strains are the bases of the study of microbial ecology. Three culturing media were used for time-interval counting of soil bacteria. Bacterial universal primers were used to amplify 16S rDNA fragments; PCR products digested by restriction endonucleases Hha I and their fingerprints analyzed for influence of culturing methods on soil microbial diversity and culturability. Results indicate that the number of bacteria grown in media LB, CSEA and WSA was 14.84×10⁷, 10.27×10⁷ and 6.91×10⁷ CFU per gram dry soil, respectively, after 192 h of incubation. The diversity index of soil bacteria was the highest in WSA, while the lowest in LB. Certain similarity was discovered in bacteria community between the three media, i.e. the Jaccard index was 57.69% between LB and CSEA, 53.13% between LB and WSA and 66.67% between CSEA and WSA. Phylogenetic analysis suggests that the dominant bacterial groups in the soil belong to β-Proteobacteria,γ-Proteobacteria and Actinobacteria. The sequence of 16S rDNA of some OTUs was found to have high homology with Burkholderiaceae bacterium, Rhodococcus and Mycobacterium, so it is presumed that the cells of these bacteria can secrete ResuscitationPromoting Factors, which may effectively improve culturability of soil microorganisms.

Abstract:Effect of inorganic fertilization on soil nutrient, soil structure and peanut yield was studied by a 20a’ long-term experiment in the Red Soil Ecological Experiment Station of Chinese Academy of Sciences. Results show that the peanut yield of inorganic fertilization treatments followed the order of NPK > NPKCa > PK > NP > NK. The difference among treatments was quite significant, showing peanut yield was significantly affected by the no-P treatment. besides slight decrease in soil total potassium, Inorganic fertilization increased the contents of soil total nitrogen, total phosphorus, available phosphorus and exchangeable potassium to some extents as compared with their initial values. Organic matter increased in all the treatments by 4.6~6.62 g kg^-1. Compared with long-term organic-inorganic fertilization, the inorganic fertilization significantly decreased the content of > 0.25 mm water-stable aggregates, increased the soil aggregate breakage rate by 9.38%~16.56%, and reduced the mean weight diameter by 0.15~0.18 mm. On the one hand, long-term inorganic fertilization improved soil nutrient contents and peanut yield, on the other hand it ruined the soil structure, which consequently affected soil nutrient availability and peanut yield. Long-term inorganic-organic fertilization might probably improve this situation.

Abstract:As every tree species is unique in biological and ecological characteristics, the presence of mono-species stands of forests, natural or planted may cause variation of soil properties away from equilibrium toward imbalance or certain extremity, which is called “soil polarization” by the author. At the same time, a number of characterization indexes, i.e. width of anti-polarization (W), resistance to polarization (R), polarization (P) and ratio of polarization resistance to polarization (I = P/R) were proposed for polarization analysis based on results of determination of soil properties of soil samples collected from a variety of mature stands of pure and mixed forests using a multi-point mixed sampling method at multiple sites in the semiarid, hilly area of loess plateau. Results show very strong polarization (P>0.20) of the following soil properties: chemical properties under Pinus tabulaeformis forest; chemical and biological properties under Platycladus orientalis, Robinia pseudoacacia and Hippophae rhamnoides forests; chemical, biological properties and trace elements content underUlmus pumila forest; biological properties under Betula platyphylla forest; and biological and physical properties under Acer ginnala forest. Among the species in this study, pure stands of P. tabulaeformis and R. pseudoacia resulted in serious depletion of soil nutrient reserves; Pure stands of P. orientalis increased soil fertility; Pure stands of U. pumila increased soil fertility but decreased trace elements content; Pure stands of B. platyphylla worsened soil biological properties; Pure stands of A. ginnala led to depletion of soil nutrient reserves and deterioration of soil biological properties; and Pure stands of H. rhamnoides did to depletion of soil nutrient reserves and degradation of soil biological and physical properties. The anti-polarization capacities of P. simonii and P. tabulaeformiswere the highest and of U. pumila the lowest. Relative to antipolarization capacity, the ratios of polarization resistance to polarization of the stands fell into the category of more than “medium” （I_a＞0.40）including chemical and physical properties under P. tabulaeformis forest, all the soil properties as a whole under P. orientalis, R.pseudoacia and U. pumila forests, and biological, physical and chemical properties under B. platyphylla forest.

Abstract:Salt absorption, transpiration induced water uptake and the radial reflection coefficient of the root system of arrowleaf saltbush (Atriplex triangularis) were measured in order to analyze ultrafiltrational characteristics of its root system in relation to salt tolerance of the plant. Results show that increase in salinity stress in the root environment resulted in increase in Na⁺ uptake, and decrease in transpirational water uptake and in radial reflection coefficient as well. However, the relative amount of Na⁺ uptake based on the salt concentration of the solutions from root bathing showed a tendency of declining with the increase in salinity stress. The amount of Na⁺ being taken into the xylem did not exhibit any significant increase with the decreasing radial reflection coefficient of the root. This indicated that arrowleaf saltbush was able to change the ultrafiltration characteristics of its root system and reduce radial reflection coefficient of the root, thus lowering the risk of higher xylem tension leading to xylem cavitation and able to reduce salt absorption to avoid damage of salt over-accumulation to the plant.

Abstract:A Trichoderma mutant strain T32, which can grow on the carbendazim-containing culture medium was isolated out of pesticide-tolerant Trichoderma strains. Its carbendazim degrading rate reached 61.4% in the mineral medium that utilizes carbendazim as the sole carbon source after 5 days of shake at temperature 25℃ and 200 r min^-1. In the medium 6.0 in pH value, 25℃ in temperature, 5% in inoculation rate and 05% in yeast addition rate, its degrading rates of five common chemical pesticides — carbendazim, procymidone, iprodione, thiophanatemethyl and triadimefon reached 91.4%, 92.1%, 55.3%, 40.1% and 86.5% respectively, demonstrating that Strain T32 has a relatively extensive degradation capacity Trichoderma can degrade five different kinds of chemical pesticides including carbendazim at the same time, which has not yet been involved in the present research on degrading bacteria. An indoor test of degrading carbendazim in original soil, natural air-drying soil and high-temperature ovendrying soil for 10 days revealed that their carbendazim degrading rate was 78.6％,75.3% and 70.5%, respectively, when the optimal degradation conditions were 25～28℃ in temperature, 5% in inoculation rate, 50 mg g^-1in concentration of carbendazim and 15% in water content. The findings may serve as a scientific basis for applying Strain T32 to bioremediation of polluted soil.

Abstract:A three-year (2005～2007) experiment was conducted in paddy fields under a double rice cropping system to study effects of continuous no-tillage and cast-transplanting on soil physical, chemical and biological properties. Results show that no-tillage treatment for one year（two crops）improved soil physical properties, but no-tillage treatment for three years (six crops), worsened soil physical properties. However, the effect of no-tillage treatment for two years varied. In the soil incorporated with milk vetch and rice straw, it decreased soil density of the cultivated horizon, but increased total porosity and non-capillary porosity therein, and helped nutrient enrichment in the surface soil layer. Soil analysis showed that the no-tillage field was less than the control, plowed field in total amount of three groups of soil microbes. However, in no-tillage field, the amount of soil bacteria increased, while that of soil actinomycosis and fungi reduced, and urease activity in surface layer soil increased, while catalase and peroxidase activity reduced. Significantly positive correlations were observed of soil organic matter and total N with urease, catalase and polyphenol oxidase activity and, significantly positive correlations of soil total N and available K with peroxidase activity and. The findings provide a valuable reference for popularization and application of the technology of no-tillage and cast-transplantation of rice in the future.

Abstract:Research on China’s soil protection strategy from state macroscopic and long term perspectives is of great significance for sustainable use and protection of soil resources, improvement of soil environmental quality, and ensuring agricultural production and food safety. Based on analysis of advancement and development trends of soil protection at home and abroad, this paper identifies some shortcomings in soil protection in China and gaps as compared to systems in place in developed countries and raises the key issues in the macrostrategy research on soil resources and the environment. These issues include (1) major problems of current soil protection in China; (2) guiding ideology and theory (namely macro strategy) of soil protection in China, comprising strategic concepts, guidance, objectives, missions and emphasis; (3) countermeasures in the soil protection strategy in China, consisting of management, standards, science and technology, regional soil protection, environmental protection and remediation of major soil types. This paper provides a useful reference for establishing and implementing strategic planning of soil protection in China.

Abstract:In view of the increasingly serious global environmental problems, this paper summarized the theoretical and practical development in science and technology of domestic and international environmental protection. Based on this summarization, we preliminarily discussed the developments of water environmental protection, soil environmental protection, atmospheric environmental protection, biological conservation and mineral resources’ environmental protection and their progresses on scientific and technological research from the perspective of earth system science, and put forward the strategic focuses of China's environmental protection, respectively. Finally, the development trend of future environmental protection was summarily analyzed.

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