Abstract:It have been studied with wind tunnel experiments that the wind erosion rule of loosing soil on the hungriness sand land of western Inner-Mengolia,the impact of wind flow with sand on the wind erosion amount,the mechanism by use of PAM to keep from wind erosion of loosing soil and its capability to withstand wind flow with sand.The samples were taken in sequences about the impact of wind flow with sand on the wind erosion amount and anterior sample applied wind flow with sand for posterior one.The 3 levels of PAM dosage(1 g/m2,2 g/m2 and 4 g/m2) and 4 wind degrees(0,17.6%,36.4% and 57.7%) was contained in the tests for PAM sample capability to withstand wind flow with sand.The results showed that the erosion ability of wind flow with sand was much more than the ability of pure wind when the wind velocity was equal and the wind erosion amounts of them were evidently different.The samples just only withstood wind flow with sand for 5 to 10 minutes with a wind velocity of 7~8 m/s when PAM dosage was 1 g/m2.However the samples would withstand wind flow with sand for 30 minutes with a wind velocity of 8~10 m/s when PAM dosage was 2 g/m2.It would withstand wind flow with sand for more than 30 minutes with exceeding 10 m/s wind velocity when PAM dosage was 4 g/m2 and the sample almost could prevent 99% of all soil erosion caused by natural winds.The dosage of 2 g/m2 PAM was recommended normally and economically in the paper for most of wind erosion(about 97%~99%) could be prevented.The surface could form a crack when PAM solution was sprayed on loosing soils surface so that it could effectually prevent from wind erosions.

Abstract:为了解沙尘暴多发区和田地区主要地表类型的土壤风蚀量情况,利用集沙仪进行了中、小尺度条件下的沙尘暴实地测定,结果表明:在中尺度下,主要地表类型沙漠、过渡带和绿洲土壤输沙量、降尘量具有显著性差异,并与覆盖度存在明显的相关性。在小尺度下观测的结果表明,不同地表类型输沙量也存在显著差异,相同高度下平均覆盖度82%的农田输沙量不足沙漠输沙量的10%,沙漠观测点下风口输沙量比上风口增长2.39%,弃耕地下风口输沙量比上风口增长7.90%,而覆盖农田下风口输沙量比上风口减少2.24%,说明提高植被覆盖对减少当地土壤风蚀的重要性。

Abstract:The process of erosion sediment yield of slope-gully system in Loess Plateau was studied by using slope-gully system physical model and runoff scouring method,integrating rare-earth element tracing technology.The results indicate that erosion rate of slope-gully system in the slope is bigger than it in the gully,that is to say,slope erosion is more serious than gully erosion.In the range of experimental flow discharges,there is a critical discharge.Erosion rate is increased with the flow increasing when the flow is less than the critical value.Erosion rate is decreased with the flow increasing when the flow is greater than the critical value.And the critical value is 12 L/min.Erosion rate is fluctuated with the scouring duration when the flow is uniform.Initiation erosion rate is increased and the time that erosion rate achieved the maximum is shorter with the flow increasing.Initiation erosion rate is increased and the time that erosion rate achieved the maximum is shorter with the flow increasing.

Abstract:研究了人工模拟降雨条件下,坡度对撒施于酸性赤红壤坡地的污泥铜随径流的迁移情况。结果表明,污泥撒施1 d后的径流中混匀样总铜(MTCu)、静置样总铜(STCu)、颗粒态总铜(TPCu)、悬浮态总铜(TSCu)浓度和流失量均达到峰值,大小依次为25°>20°>15°>10°,其中25°MTCu、STCu浓度和流失量峰值分别高达6 475.8,300.2μg/L和90.78,4.32 mg/m2,分别是10°对应峰值的4.6,3.4倍和5.7,4.6倍。随时间推移,各坡度撒施径流MTCu,STCu,TPCu,TSCu浓度和流失量总体呈递减趋势,坡度引起的径流同期铜浓度和流失量差异逐渐变小。10°~25°处理径流中75.4%~92.9%MTCu和65.1%~73.5%STCu流失量发生在污泥撒施前期(1 d和18 d)径流中,MTCu径流流失系数为0.48%~1.75%,颗粒态铜是铜随径流流失的主要形式。

Abstract:Base on the theory of erosion dynamics,geomorphology,hydrology,mechanism of sediment transport,a distributed soil loss model was built and applied in Chabagou watershed in sandy areas of Yellow River by using GIS technique,the model could be used to count the amount of soil loss on watershed loess slope,gully and groove,the model is capable to coupling the runoff process and sediment transport;raised the concept of equivalence estimation roughness coefficient,preliminary solve the problem soil and water conservation project to change runoff,so the model could forecast the benefit on different control plan of soil and water conservation;the soil loss imitation forecast information were extracted use 3S technique;built the definition method of classification template in virtual reality environment to improve the classification precision of remote sensing image,prefect solve the problem to distinguish the phenomenon " the different thing with same spectrum and the same thing with different spectrum".Compare to the soil loss amount measured in Chabagou and Xingzihe watershed,the model could rightly to mirror the rule of watershed soil loss in Yellow River sandy areas.

Abstract:The soil water and the physical and chemical properties of soil were studied.The results showed that: with increase in age,the site quality of plantation for wind protection and sand fixation was changed obviously,bulk density decreased,soil porosity increased,soil water holding capacity improved and soil fertility enhanced,the physical and chemical characteristics of soil were improved to some extent.With the planting of plantation for wind protection and sand fixation,the trend of soil water decreasing became the limiting factors for vegetation renewal and rebuilding and the stability of plantation for wind protection and sand fixation.

Abstract:Field measurement of airflow at 2 m high over semi-fixed longitudinal dune surface was made in the southern part of Gurbantunggut Desert in order to understand the various change of flow velocity over this dune type.It was found that wind velocity varied over the dune surface and the changes associated with primary wind magnitude and direction and slope morphology.The airflow velocity increased up the stoss slope and decreased down the lee slope.A very strong linear relationship exists between amplification of wind velocity and primary wind speed.The large the incidence angle between primary wind direction and dune is,the greater the extent of wind velocity tended to be.The landform has a significant effect on the airflow as well.There is a slow change of wind velocity down the gentle slope but a great change when the slope is steep.

Abstract:Through simulating artificial rainfall in sloping land,this study investigated the impact of soil surface crust on runoff,sediment,and phosphorus and potassium losses from the different lands with no crust,light crust or heavy crust.Results showed that,heavy curst decreased runoff discharge and sediment loss.The declining process of phosphorus and potassium losses with runoff and sediment was a power equation,and the losing velocity of phosphorus and potassium was the fastest for no crust land.With the different development status of soil crust from no crust to heavy crust,the dominant position of the sediment extractable potassium loss was replaced gradually by the dissolved potassium loss,but the extractable phosphorus loss was dominant all the time.As compared with no crust land,the total amount of phosphorus and potassium loss was decreased by 20% and 9% for light crust land respectively,and reduced by 52% and 77% for heavy crust land respectively.It implies that soil crust may decrease soil nutrient loss and control soil quality degeneration tendency.

Abstract:Ephemeral gully erosion is an important erosion type in Loess Plateau.this article explained the concept of ephemeral gully and ephemeral gully erosion,and reviewed the development process of ephemeral gully erosion.This paper emphatically analyzed the major influencing factors of ephemeral gully development,and according to these factors,prevention measures of reduced the ephemeral gully erosion have been suggested.

Abstract:采用土体损失、水分损失、养分损失(N,P,K,有机质含量)及泥沙滞留损失和泥沙淤积损失等5种实物型损失作为水土流失经济损失的评估指标,在全省土壤侵蚀调查基础上估算出湖南省及其各地水土流失经济损失的货币值。结果显示,湖南省水土流失的经济损失巨大,2000年全省水土流失经济损失货币总值达99.51亿元,占当年全省国内生产总值的2.73%,相当于全省农业总产值的11.35%,构成全省人均损失151.65元,农业人均损失212.72元,平均每1 km2水土流失经济损失4.65万元。其中,养分流失是湖南省水土流失经济损失的主要形式,占损失总量的75.12%;中度侵蚀类型造成的水土流失经济损失最为严重,占总量的68.51%;与1995年相比,全省2000年水土流失的经济损失总量呈减少趋势,主要是中度侵蚀的经济损失有所减少,而中度以上侵蚀造成的水土流失经济损失反而有所加大。同时,80%以上地区有不同程度的减少,地处全省水土流失最严重区域的湘西自治州和张家界市水土流失经济损失反而有所加大。

Abstract:Estimation of the surface runoff of a basin is one of an important study theme of hydrology.In the current study,a basin named Liudaogou which located at north Loess Plateau was chosen as a study location.Based on consideration of the actual terrain and soil physical properties,we developed a numerical calculation model by using kinematic wave theory and the hypothetical channel network for simulating the process of "Rainfall-Runoff" of a distributed-type basin.The simulated results of the observed-discharge shows this numerical calculation model is applicable to the study location.Therefore,an effective numerical calculation method for estimating the surface runoff of north Loess Plateau region was proposed.

Abstract:在分析积水入渗条件下短历时Philip入渗公式特点基础上,建立了基于短历时Philip积水入渗公式的降雨产流模型。模型显示地表积水时刻与雨强平方成反比。利用降雨强度为0.082 cm/min、坡度为15°情况下实测累计降雨产流量推求了模型参数吸渗率,并利用获得的S分别计算了雨强为0.214 cm/min、坡度为5°,雨强为0.133 cm/min、坡度为5°和雨强为0.133 cm/min、坡度为15°情况下累积径流量,相对于实测累积径流过程,计算相对误差都在10%内,可以满足精度要求,说明基于短历时Philip入渗公式建立的降雨产流模型可以用于描述坡面降雨产流过程。

Abstract:For investigating the land use change and developing trend of Yulin,By using image processing module and computerized interpretation module of Erdas, seven land use types(grassland,farmland,forest,unused land,desert,construction land and water) derived from the remote sensing images in 1993,2000 and 2006 of Yulin.Furthermore,the data processing function of Excel and statistic analysis module of ArcGIS conducted the analysis of land use change from 1993 to 2006.As a result,this paper obtained a set of land use change diagrams and transfer matrix charts of land use,and it summarized the characteristics of dynamic change of land use in the past thirteen years.The result indicates that:the comprehensive dynamic state degree is present to down-trend;each kind of land use of a type changes fast variety to increase or decrease on the space;three indexes can be more availability to reflect the Yulin area variety circumstances.

Abstract:This article uses the localization to take a sample and to dry the law,has determined the Yulin sand district several trees soil moisture.The results are as follows: soil moisture content's vertical distribution pattern is lowest for the surface layer soil moisture content,along with depth of soil increase,the soil moisture content assumes increases the tendency;Soil moisture content's season dynamic rule has the obvious seasonal variation rule for the different tree species soil moisture content,the soil moisture content may divide into three stages according to the seasonal variation,soil moisture weak dehydration stage from April to May,soil moisture consumption stage from June to August,soil moisture restores the stage slowly from September to October;Various trees' soil moisture change rule for Pinus sylvestris var.mongolica>Caragana korshinskii>Amorpha fruticosa>Salix psammophila>Artemisa arenaria DC.>Hedysarum scoparium-Hedysarum fruticosum.

Abstract:通过调查分析重庆四面山5种人工林的林下枯落物储量,研究了各林地枯落物持水特性。结果表明:5种人工林林下枯落物储量及其持水量均表现出:分解层>半分解层>未分解的变化趋势。在相同林龄条件下,石栎×木荷混交林林下枯落物储量最高(246.94 t/hm2),其次是杉木×马尾松混交林(202.79 t/hm2)和枫香×木荷×石栎×香樟×灌木混交林(191.82 t/hm2),杉木人工纯林(39.73 t/hm2)最低。试验研究的5种林地中,石栎×木荷混交林林下枯落物的24 h最大持水量最大,为254.28 t/hm2,杉木×马尾松混交林(191.72 t/hm2)和枫香×木荷×石栎×香樟×灌木混交林(168.21 t/hm2)次之,杉木人工纯林最小,仅为31.66 t/hm2。经统计分析,试验5种林下枯落物未分解层、半分解层和分解层三者持水量与浸泡时间之间均符合为W=aln(t) b,且三者的吸水速率与浸泡时间之间亦符合S=ktn的关系式。研究表明,石栎×木荷混交林林下枯落物是5种林地中持水性能最好的一种,而杉木人工纯林枯落物持水性能最差。

Abstract:Spearman rank correlation analysis and grey relational grade analysis were used in the research for soil water infiltration characteristic of different forest lands in Simian Mountain.The results indicate that soil bulk density,the contents of grit and non-capillary porosity have significant correlations with soil saturated hydraulic conductivity.Non-capillary porosity and the contents of grit are positive correlated with soil saturated hydraulic conductivity.Soil bulk density is negative correlated with soil saturated hydraulic conductivity.Based on the initial infiltration rate,stable infiltration rate,infiltration time and cumulative infiltration which were the important parameters determining soil infiltration characteristic,the results from grey relational grade analysis show that the values of grey relational grade in different forest lands took turns as broadleaf forest(0.803 1)>P.pubescens forest(0.786 9)> mixed broadleaf-conifer forest(0.445 4)> coniferous forest(0.403 9).Broadleaf forest has the better infiltration capability between researched forest lands.The values of correlation coefficients which Horton infiltration model simulated in researched forest lands are more than 0.950,so it has good applicability for researched forestry soil infiltration processes in Simian Mountain.

Abstract:在陕西渭北旱塬进行了4年田间小麦试验,研究了旱地不同栽培模式、施氮量和种植密度对土壤硝态氮残留累积的影响。结果表明,种植小麦4年后,0-200 cm土壤剖面中残留硝态氮为29.87~462.59 kg/hm2,且主要积累在80-160 cm土层,土壤氮库不仅明显,且残留比前3年土壤剖面显著下移(前3年主要累积在100 cm),差异达显著和极显著水平;不同栽培模式和种植密度0-200 cm土层硝态氮残留累积规律及其小麦籽粒吸氮量基本相似,排序均为:地膜覆盖>常规种植>秸秆覆盖>垄沟种植;随施氮量的增加土壤硝态氮残留量也相应增加,N0处理0-200 cm土壤平均硝态氮残留量为57.69 kg/hm2,N120处理平均为97.04 kg/hm2,虽然高于无氮处理,但两者差异未达到显著水平,N240处理平均为355.43 kg/hm2,比前者增加的幅度更大,其差异达到极显著水平。因施氮肥而增加的土壤硝态氮残留量为14.9~401.18 kg/hm2,平均占4年施氮量的19.59%,其中地膜覆盖占26.07%,常规种植占20.98%,秸秆覆盖占17.46%,垄沟种植种植占13.87%。

Abstract:In order to investigate the effect of soil water,fertilizer and temperature management on the NO-3-N transport of soil in greenhouse crop production,a simulation experiment using the soil columns was inducted to determined the changes of NO-3-N transport rate and its gradients in soil vertical profiles under various vaporization temperature,initial soil moisture and NO-3-N contents for a 5 year greenhouse soil sample.The results showed that vaporization temperature and initial soil moisture had an influence effected significantly NO-3-N transport to top soils,and the transport rate increased with the increase of vaporization temperature and initial soil moisture.The effects on NO-3-N transport rat were a descending order of initial soil moisture,vaporization temperature,and their interaction.The effects of initial NO-3-N contents in soil and its interactions with vaporization temperature and initial soil moisture on NO-3-N transport rate were not significant,but it effected the absolute NO-3-N contents of soils.After water was evaporated in soil for 5days,it showed that NO-3-N content was higher in top layer soil and decreased with increase of soil depth,rose a little again and tended to a approximate steady value.A model for NO-3-N transport rate was determined under steady vaporization.This model can be used to predict NO-3-N transport rate to top soil for greenhouse under the different fertilizer and soil environment.

Abstract:Based on long-term fertilization experiment for 26 years in paddy field,the effects of long-term fertilization on profile distribution of soil nitrogen and C/N,Soil nitrogen mineralization characteristics,nitrification rate and relationship between cumulative mineralization and effective accumulated temperature were studied,the result showed:(1) Topsoil nitrogen accumulation significantly increased,profile distribution curves of soil nitrogen were in 'S' shape.Total nitrogen contents of 0-20 cm soil layer of organic manure treatments were higher than that of chemical fertilizer treatments.In 20-30 cm soil layer,nitrogen content of CNP,CNPK and C0 was higher than MNP,MNPK,MRN and M0.There are little differences of nitrogen contents in 40-50 cm soil layer;(2) Soil nitrogen mineralization curves were significantly different in prophase.Mineralization of different treatments general reached maximum after 7 d and tended to be stable after 28 d.Mineralization of organic manure treatments was higher than that of chemical fertilizer treatments after 7 d.Cumulative mineralization and effective accumulated temperature were in good accord with effective accumulated temperature model.Mineralization constant K and n reflected that organic manure treatments may had more mineralization potentials and mineralization processes of chemical fertilizer treatments may require more time to reach stable state;(3) Nitrification rates of all treatments were increased,organic manure treatments were higher than chemical fertilizer treatments,CRN was higher than CNP and CNPK.Nitrification rate of MNPK was the maximum and increased 6.44 times compared with C0;(4) Organic manure and straw applications may result in C/N of topsoil decreased.For C/N of 0-10 cm soil layer,CNPK>MNPK,C0>M0,MRN was the lowest.For C/N of 20-50 cm soil layer,Organic manure treatments were general higher than chemical fertilizer treatments,and subsoil of chemical fertilizer treatments had higher degree of SOM decomposition.

Abstract:Laboratory analysis was conducted to investigate nitrogen mineralization of soils in the Loess Plateau of China.The aims of our study were to determine the content of SON(soluble organic nitrogen),and the percent of TSN(total soluble nitrogen) to SON,and the relate SON to mineralized nitrogen.Results showed that the content of SON of all soils increased significantly during incubation.The percent of TSN to SON was the highest at start stage.From day-0 to day-3,the percent declined to the lowest level.After that the percent increased gradually.In the end of incubation,SON accounted for 24% of TSN.Soil mean mineralization potential(N0) based on total soluble nitrogen(45.8 mg/kg) was a quarter higher than mean mineralization potential(36.5 mg/kg),which was based on mineralized inorganic nitrogen.The positive relationship was found between the content of SON and mineralization potential that based on mineralized inorganic nitrogen,but not reach significant level.Our results suggested that in order to evaluate nitrogen mineralization,the content of SON was only measured during incubation may underestimate mineralization potential and the amount of nitrogen losses.

Abstract:Direct and accurate calculation on three-dimension watershed geomorphology is one of key issues in current fractal geomorphology.Based on the Fundamental principle of variational method,the three-dimension surface fractal dimensions of a indoor small watershed model were calculated.And based on DEM data of the watershed model under different development periods as well ad the function of windows analysis in ArcGIS 9.2,the three-dimension geomorphology minkowski dimension of the watershed model under different development periods were calculated and studied.The results indicated that: the organic combination of variational method and GIS makes it possible to calculate directly the three-dimension geomorphology fractal dimension,and the three-dimension geomorphology of the small watershed model under different development periods possess good fractal characteristics in non-scale range respectively.In addition,three-dimension geomorphology minkowski dimension not only indicates effectively the variations of the geomorphology of the indoor watershed model under different development periods,but also reflects accurately the dynamic characteristics of watershed geomorphology,as a result,it is feasible to make three-dimension geomorphology minkowski dimension as a quantitative index of the three-dimension geomorphology fractal character of the small watershed model.

Abstract:对福建省建瓯市山地红壤的农业用地(坡耕地、茶园、桔园)、林地(杉木、木荷、封育)不同土层(0-10,10-20 cm)土壤团聚体有机碳含量与贮量进行研究.结果表明:林地开垦作为农地后,>2 mm土壤大团聚体的数量明显下降,<0.25 mm团聚体含量显著上升.不同土地利用方式的土壤大团聚体呈现粒径越大,团聚体有机碳含量越高的趋势,林地不同粒径团聚体有机碳含量都显著高于农业用地.林地随着团聚体粒径增大,土壤碳贮量增加;而农地正好相反,随着团聚体粒径增大,土壤碳贮量反而下降.土壤总有机碳增加主要受到大团聚体有机碳增加的影响,其中>2 mm和0.5～2 mm粒径土壤团聚体对土壤总有机碳贡献最为突出.因此亚热带山地红壤内林地开垦为农业用地会导致富含碳的土壤大团聚体有机碳含量大幅度下降,团聚体的稳定性也随之下降.

Abstract:通过8年田间定位试验,研究了不同施肥制度下褐土及其微团聚体有机碳活性变化规律。结果表明,褐土微团聚体有机碳活性随粒级的减小而增强,不同施肥制度下土壤微团聚体组成变化各异,不施肥主要是由于10~50μm粒级总有机碳和<10μm粒级易氧化有机碳储量减少而造成土壤有机碳活性降低,土壤肥力下降;单施常量NPK化肥处理呈同样的趋势;增量NPK化肥可保持有机碳活性和肥力不降低,但投入较高;有机肥(物)料配施常量NPK化肥主要是通过增加大粒级特别是10~50μm粒级总有机碳和易氧化有机碳储量而使有机碳活性和土壤肥力水平得到提高。采用有机肥(物)料配施常量NPK化肥是改善褐土肥力的有效措施。

Abstract:The successional rule of vegetation and dynamics of soil nutrient elements after 22-years' natural restoration were studied in karst disturbed area in northwest Guangxi,which would promote the degraded ecosystem restoration and reconstruction in northwest Guangxi.The study was employed overall and sample quadrate investigation method and taken the climax community in Mulun Natural Reserve in Huanjiang County as control.The results showed that the diversity lost severely in the disturbed area with only 26.6% species of that in Mulun Natural Reserve.With the succession and development from grass,grass and bushes,bushes,liana and bushes,trees and bushes to the climax community,the community heighty,biomass,plant diversity,soil organic carbon,soil nutrient,cation exchange capacity(CEC),and the content of Si,Fe,Al,and Ti increased gradually.However,the content of Ca and Mg reduced remarkably,the value of pH decreased.All this indicated that the soil quality improved with the vegetation recovery basically but with slight drop in the stage of liana and bushes.

Abstract:A field experiment on Summer Corn in Beijing was conducted to investigate the effects of drip irrigation frequency on soil moisture,heat and maize growth.The results show that,the soil moisture remains relatively stable at the whole growth period under high-frequency irrigation.Soil temperature is significantly affected by soil moisture distribution,air temperature and the stage of crop growth,and the air temperature plays a primary role to soil temperature at 10cm deep.Soil temperature tends to be stable at the depth of 50cm and below,however,it also rise gradually with the increasing air temperature.Although the high-frequency irrigation is accompanied with high yield,this treatment has lower water use efficiency yet.Thus,intermediate-frequency irrigation is more advised for the summer corn of North China with the comprehensive consideration of economic efficiency and water use efficiency.

Abstract:The effects of sodium polyacrylate(SP) on soil,water-holding capacity at different suctions of sand,silt and clay were evaluated by using centrifugal Method.Five rates of SP,0.0%,0.01%,0.08%,0.2%,and 1%(on dry weight basis),were added to these three soils.The effects of SP on yield and WUE of winter wheat and the following maize were studied.SP was dusted on the upper layer with 2gm/m2after the wheat was sown and the maize was planted on the field without any treatments after the wheat was harvest.The results show that the amount of water retained by the soil at each suction over the range of 0.01MPa to 1.5 MPa significantly increased with increase of SP;The effects on sand were more obviously than silt and clay;It is suggested the concentrations of SP be controlled from 0.08% to 0.2% by weight and the best rate is 0.2% of each soil.Then the capillary prosity of sand,silt and clay were increased 138.61%,37.22%,62.70% respectively compared to the CK.Without added irrigation,the yield and WUE of SP treated wheat were increased 4% and 5.7% respectively compared to the CK while increased 1% and-1% respectively with added 28.5mm irrigation at filling stage.The yield and WUE of the maize planted on the SP treated plot were increased-0.5% and 3% respectively compared to CK.The effect of SP on the yield and WUE of maize was less obviously than on the wheat.

Abstract:Pot experiment was conducted to study the effects of three controlled release fertilizers(CRFs)on growth of calla in comparison with common compound fertilizer and to investigate leaching loss rate of nutrients in CRF by measuring nutrients content in leachate.The results indicated that the plant height,growth potential and chlorophyll content in CRF treatments were better than those in common compound fertilizer treatments and control.Changes of pH of leachate were always smooth during the whole growth season of calla because controlled release compound fertilizer could release nutrients slowly,which could reduce the leaching loss rate of N,P,K effectively,provide sufficient nutrients for the flowering of calla,and thus keep balance of the growth of calla.

Abstract:The aim of this study was to determine the effects of urban sewage on the physiological responses of five hydrophytes and to analyze the differences in their tolerances under sewage stress.Five common ornamental hydrophytes: Reinekea carnea(Andr.) Kunth.,Acorus gramineus Soland.,Alisma orientale(Sam.) Juzepcz,Acorus calamus L.,Iris pseudacorus Lim.,Lythrum salicaria L.were used to study levels of malondialdehyde(MDA),the levels of proline(Pro) and activities of peroxides(POD) and catalase(CAT) in their leaves,membrane permeability(MP) and activity of root under urban sewage for 5,10,15 days.Hydrophytes vary in tolerance to urban sewage.Among them,Iris pseudacorus Lim.exhibited highest tolerance,there were no significant differences in MP and MDA between control and Iris pseudacorus Lim.,while those in some other plants increased compared with control;On the other hand,the increase of levels of Pro,activities of POD,CAT and activity of root in Iris pseudacorus Lim.,enhanced activity of root in Acorus calamus L.,activities of POD,CAT in Lythrum salicaria L. and activities of POD,CAT and activity of root in Alisma orientale(Sam.) Juzepcz are physiological characteristics of hydrophytes related to tolerance under urban sewage stress.These ornamental hydrophytes are suitable for scavenging urban sewage and Iris pseudacorus Lim.is most recommendable one.

Abstract:Effect of pH and aeration for nitrogen and phosphorus in eutrophic water by aquatic plant on floating-beds was investigated in the greenhouse in this study.The present experiment was studies at different pH after 6 d treatment,removal efficiencies for TN,CODMn,and BOD5 were highest at pH8.9,TP removal was highest at pH6.7,Chla removal was highest at pH5.0 in the planted system.However,removal efficiencies of TN and TP were highest at pH8.9,BOD5 removal was better at pH6.7,removal for Chla and CODMn was highest at pH5.0 in the unplanted(control) system.TN removal was influenced significantly with aeration after 6 d treatment in the planted and unplanted system,and its removal with aeration treatment was much smaller than that with not-aeration(P <0.001).CODMn removal was affected by aeration except for watercress system,but removal of TP and Chla was not impacted by aeration.The results showed that removal efficiencies of NH4-N,NO3-N,and NO2-N were highest at pH8.9 and pH8.9 aeration.

Abstract:Artificial heavy metal contaminated seawater was added into the sediment with different contents of humic acid(HA),and the partitioning of heavy metal was analyzed.Transformation of extrinsic heavy metals in the water-sediment system under the influence of HA was researched.The results indicate that the HA content has the obvious influence on heavy metals in the absorbing capacity and the speciation,especially on the acid extractable form and the reducible form.But the different degree of influences is showed for the different elements.The HA has the significant effect on Cu and Pb while has the inapparent effect on Zn and Cd.Because the estuarine wetland sediment is in the higher salinity environment,the ion concentrations in seawater would influence the interaction between HA and heavy metals.Therefore there are some differences for the effects of HA on bioavailability of heavy metals between estuarine wetland sediments and soils.

Abstract:选择长江三角洲地区代表性人为耕作土壤青紫泥为研究对象,通过网室盆栽试验研究了青紫泥-水稻作物系统中汞的微生物学效应。结果表明:水稻收获后,除土壤的代谢商随汞处理浓度的增加而增加外,不同汞处理后土壤微生物量碳、呼吸强度和微生物生物商均表现为在低浓度汞处理(≤1.5 mg/kg)时有促进作用,在高浓度汞处理(≥2 mg/kg)时则表现出抑制作用。综合来看,土壤微生物商是汞处理后比较敏感的微生物学指标。此外,种植水稻后,随处理水平的增加,与对照相比,青紫泥各汞处理土壤微生物群落的代谢剖面AWCD值均降低;青紫泥中各处理的AWCD值均随培养时间的增加而增强,且呈"S"型指数增长模式;青紫泥中各处理的Simpson指数和McIntosh指数均比对照低,其中Simpson指数和外加汞浓度之间存在显著的相关性,可作为反映青紫泥微生物群落结构受汞污染程度的有效指标。

Abstract:To study effects of different restored vegetations on soil microbial community activities in a degraded ecological system,and probe into the sensitive and reliable indicating index for revealing suitable vegetations in local ecological conditions.The results showed that soil microbial biomass C,N,P and soil microbial quotient,soil enzymes such as sucrase,urease,catalase and alkaline phosphatase were significantly different(P<0.05) in the restored Agriophyllum squarrosum,Artemisia sphaerocephala kasch,Caragana korshinskii,Ammopiptanthus mongolicus and artificial arbor(Pinaceae sylvestris L.Var.mongolicus Litv.mixed with Robinia pseudoacacia L.) stands.In soil profile,soil microbial biomass C,P and N in Caragana korshinskii stand were relatively high except for soil microbial biomass N at upper soil layer in artificial arbor stand,and they were low in Agriophyllum squarrosum stand;soil microbial quotient didn't have obvious trend in the restored vegetations stands.Activities of sucrase in artificial arbor stand and urease in Caragana korshinskii stand were relatively high,the activities of catalase and alkaline phosphatase also didn't have regular trends,and the activities of sucrase,urease and catalase were relatively low in Agriophyllum squarrosum stand and so was the activity of alkaline phosphatase in Artemisia sphaerocephala kasch stand.Analysis of variance(ANOVA) explained that the relations between tested soil enzymes,soil organic matter and soil total N and soil microbial biomass C,N,P was closely correlated,principal component analysis indicated that soil microbial biomass C,N,P,sucrase and soil microbial quotient expressed the main information on the response of soil microbial community activities to the restored vegetation in studied area.From the changes of soil microbial community activites in the restored vegetation stands it is indicated that Caragana korshinskii and artificial arbor are suitable vegetation restoration types to local ecological conditions.

Abstract:In the wind-water erosion crisscross region on the Loess Plateau,the existence of stone fragments influences soil water hydraulic properties and restricts plant water efficiency.Therefore,results of this investigation for seepage flow of soil-stone mixtures could be useful to vegetation restoration in this region.Although there are a lot of researches on the seepage flow of underground water,few of them are for soil stone mixture because of its largely increasing scale of FEM solution.By employing rectangular element of sub-domain technique of finite element model and assuming that the increase of stone content in the mixture has no effects on porosity of soil and that stone is a material of no seepage,this work has analyzed the seepage flow of soil stone mixture.The computational results of this model show that the main factor which affects saturated water conductivity of soil stone mixture is the stone contents,while the stone size almost has no influence on it.However the distribution layout of stone in soil of this model is the second affecting factor for the average seepage flow velocity if the stone layout increases the length of seepage flow path.And the numerical achievements are in good agreement with some author's theoretical results and experimental results.The sub-domain method is of high computational performance and accuracy.And it can be used for analyzing large scale seepage flow in soil stone mixture.In addition,the method could be generalized for 3D analysis of soil stone mixture and for larger scale simulation of seepage by multi-sub-domain technique.

Abstract:提出了一种地表-地下径流联合模拟的分布式水文模型,该模型综合考虑了地表径流、土壤水、地下径流之间的相互作用和水量交换,更真实地模拟了径流系统。选取太湖西苕溪流域进行了模型的应用研究,采用1km×1 km网格,就1988-2001年横塘村、范家村两水文站逐日、月实测径流资料进行径流模拟,确定了模型的基本参数。从模拟精度、参数需求、模型稳定性、水量平衡等方面分析模型的特点,研究表明:该模型参数相对简单,模拟精度较高,耦合运行稳定、快速,水量平衡分析详尽。模型可用作地表-地下径流相互作用、流域水量平衡分析和水资源管理的有效计算工具。

Abstract:Annualized Agricultural Non-Point Source model(AnnAGNPS),a continuous-simulation,watershed-scale model,is widely used to evaluate non-point source pollution from agricultural watersheds in a number of countries.AnnAGNPS simulates surface water,sediment,nutrients,and pesticides leaving the cells and their transport through the watershed.The Daning river watershed was selected as the case study.Based on 3S(GIS,Remote Sensing,Global Position System) technology,the AnnAGNPS model database was set up in the watershed by analysis of rainfall characteristics,size of simulating cells,translation of soil relative parameters,characteristic of land use management,and so on.The parameters on climate,topography,soil,landuse,crop information and crop management were evaluated.This study was expected to provide a sound and credible basis for decisions to evaluate soil erosion,sediment and agricultural non-point source pollution in Daning river watershed and Three Gorges Reservoir Region.

Abstract:In this study NDVIC,assigned as the NDVI value in an effort to eliminate the influence of rainfall,based on time series of rainfall data and temporal SPOTVEG NDVI data,was used to evaluate the effects of "Grain for Green " project for the period 1998-2005 in Yulin,Yan'an,Xi'an and Ankang of Shaanxi Province.A strong relationship existed between rainfall and integrated NDVI(monthly) for all four sampling domains(R = 0.27 to 0.82),while the correlation coefficient increased from south to north.Vegetation coverage has increased in Yan'an from 1999 to 2005,especially in 2002-2005,showing some correlation with the climate variables,especially rainfall(1 month time-lagged),but precipitation alone don't fully explain the increased green cover.Increased NDVIC in October expresses an obvious effect of GFG on the vegetation change.It provided a thought for objective and repeatable evaluation of effects of "Grain for Green" program.

Abstract:Measured the cover soil water content in soil layer 0-30 cm of different agroforestry landscape types in Ji-yuan with TDR,the landscape types including sloping cropland,apple orchard,apple-clover system,land under forest and grass changed from grain crop and black locust forest.Analyze the distribution characteristic and spatiotemporal variability of the cover soil water.The result showed that the soil water has renewed in a certain extent after a rain period in 1.5 m soil profile;the soil water content is gradually increased from the top of to the bottom of the slope under the affection of the slope location and plant category.The theory model of semivariogram for cover soil water content before rain season and after season,the value of nugget is changed no obviously,and they are 0.25 and 0.30;ranges is 99.7 m and 87.6 m.And the results indicated that soil moisture exhibited high fractal dimensions and clear spatial autocorrelation.The fractal dimensions are 1.71 and 1.74,variogram is main autocorrelation.During rain season the theory semivariogram model is linear,the spatiotemporal variability of soil water content becomes higher with the increase in distance,and its fractal dimension is 1.40.

Abstract:The observations of a study of soil heavy metal pollution situation and its spatial distribution regulation with sample as Changxing County of Huzhou City of Zhejiang Province on the GIS platform showed that: the averaged Hg and Cd as well as Zn contents in vegetable-cultivated soil were obviously higher than the local background values,and the average contents of As,Cr,Pb and Cu were near or lower than the local background values.Also,the heavy metal contents in the vegetable-cultivated soil of Changxing County mostly were lower than the accepted standard values for national non-hazard vegetable production bases.As an exception,Hg and Cd contents in 10.4% and 4.5 % of sampling sites were higher than the standard values,and Hg and Cd contents in 43% and 58.0 % of sampling sites were higher than the local background values.The maximum values of Hg and Cd in soils were as high as 945.85 ng/g and 478.88 ng/g,respectively.We found that the spatial distribution features of soil Hg and Cd in the vegetable-cultivated region were agreed with the distribution of industry regions.This implied that industry pollution will be the main factor of higher contents of heavy metals in the vegetable-cultivated soils.Besides,we have found a accumulation tendency in soil Cr,Zn and Cu contents in some parts of Changxing County.

Abstract:Pot experiments were actualized to investigate uptake and bioconcentration of heavy metals(Cu,Zn,Pb,Cd,Cr and Ni) in Pak-choi(Shanghaiqing),Pe-tsai and Radish under the influence of simulated acid rain.Compared to the control,the soil treated with simulated acid rain and heavy metals significantly enhanced the content of Cu,Pb,Cr and Ni in the vegetables,and generally,increased the content of Zn and Cd only under condition that the added Zn or Cd in the soil was quite high.Acid rain and heavy metal compound pollution makes bioconcentration factors(BCF) of Pb and Ni increased,Cu increased and Cd descended in the most cases,and BCF of Zn and Cr appear obvious difference among various vegetables.BCF of some heavy metal in various vegetables appears Radish > Pak-choi > Pe-tsai,and BCF of heavy metals in some vegetable appears Zn > Cd > Ni > Cu > Pb > Cr.Correlation coefficient between the total content of some heavy metal in the soil and its content in the vegetables attains a significant or a very significant level.Guidelines for health risk to heavy metals in the vegetable plantation soil was estimated according to BCF of heavy metals in Pak-choi,Pe-tsai and Radish.These results are important to develop environmental capacity assessment,and to draw remediation goal of soil heavy metals pollution and parochial soil ambient quality standards.

Abstract:With the combination of GIS technology and remotely sensed data,cultivated land changing trend in regional scale can be easily traced and inventoried in time.Six periods of land use spatial data bases were established with remote sensing imagery data and scanned topographic map in ARC/Info 9.0 software.The cultivated land changing feature and mutual conversion with other land use were analyzed quantitatively.It was found that cultivated land drastically changed in the past 50 years.The cultivated land was only 17 133.8 km2 in 1954,the proportion of cultivated land only amounted to 15.91% in Sanjiang Plain;while the cultivated land amounted to 51.17% in 2005,which was 55 688.45 km2 in total area.Cultivated land increased 38 554.64 km2 in the whole study periods,and the average increased area is 755.97 km2 per year.By mutual conversion analysis of cultivated land and other land use,it was found that reclamation of wetland was the main contributor for cultivated land increase,and forest and grassland converted to cultivated land was another reason for its increasing.Cultivated ratio and changing rate were applied to analysis the cropland dynamics characteristics in the past 50 years,it was found that cultivated land changing area and rate showed significant variation during different study periods.Population increasing,large amount of immigrant swarming into Sanjiang Plain as result of national policy,enhanced by agricultural technology development was the main reason for the cultivated land increase in the whole study periods.Still,it should be notice that natural conditions also played an important role in the cultivated land changing trend,especially,topographic and soil environment cast an impact on cultivated land changing location,and its pattern as well.