Abstract:In this paper, 6 phrases of satellite images include Corona、TM、SPOT、ETM+ data which represent the information of Changshu of 1966, 1984, 1992, 1999, 2000, 2001 respectively were dealt with multi-band composition, image enhancement, precision emendation, interpretation index establishment, computer assistant visual interpretation.Vector maps of expanding towns of Changshu City from 1966 to 2001 are made by interpreting images above.The statistical result shows that the area of city is 6.4 times bigger in 2001 than in 1966.From 1984 to 2001, it becomes bigger and bigger of average area of town of every person for 24 towns.In expending space, city expending is affected by geography, physiognomy condition, economic level and policy decision-making.Extending directions of most of towns are accordant with the main rivers and major roads.There is significant difference in amount and relative rate in the extending among 24 towns, and there is geographic disciplinarian in the distribut ion of towns at different expending levels.Most of towns that have large expanding rate have convenient communication, but towns that have low expanding rates are far from major roads and rivers.According to many years statistics of city expanding and historical social and economic data, it is found that city expanding is related to rural urban migration, GDP and original dimension evidently, while is not to total population, total families, total industry production and total employee.Through the statistic, we found that there is significant difference in the values of GDP of per urban area among 24 towns.

Abstract:An analytic method for determining detachment rate of concentrated flow in erosion rills was advanced in the paper.By making use of the functional relation of sediment load with rill length and the corresponding regression parameters obtained from simulated erosion experiments this method estimated functional relations of detachment rates of concentrated flows with rill length.Then relationship between detachment rate and sediment load in the flowing water was derived from this function.Comparison of the detachment rates thus computed with those directly estimated on the basis of experimental data was conducted to prove feasibility of this method.

Abstract:Film drip irrigation, which combines advanced dripping irrigat ion with film planting, is able to provide good environment for crop growth and a new concept for dealing with water crisis and exploitation of salinized land.Laboratory infiltration simulation was conducted to study water movement and solute transport in film drip irrigation as affected by dripping rate, accumulated infiltration, initial soil moisture content, initial soil salt content etc.The results showed that water content around dripper increased with increasing dripping rate which deterred the formation of desalinization zone where crops can grow.Increase in accumulated infiltration increased the volume of wetted soil and favored the formation of desalinization zone.As initial soil water content increased the volume of wetted soil and water content around dripper also increased which inhibited the formation of desalinization zone.The increase in initial soil salt content would decrease the desalinization coefficient.The present study provided useful data for the design of film drip irrigation system and practical measurement for the utilization of salinized land.

Abstract:Field soil bores measurement and static C₂H₂ inhibition soil cores method was used to study N₂O emission in the loess soil profile and the factors affecting its production.Significant spatial variation and temporal variation of the nitrous oxide amount were found in the soil used.The temporal variation was correlated with the water supply (such as rainfall or irrigation), and N₂O peaks were occurred 3 days after water events.Both the control and fertilized plots have the same trend.August was the highest N₂O production month during the period.At the highest point the N₂O concentration in the fertilized plot was 2.5 times higher than that in the control plot.Meanwhile N₂O spatial variation in the profile followed the order: 10cm< 30cm< 150cm< 90cm< 60cm.Carbon was the limited factor that controled denitrification in the soil.When carbon was supplied, nitrate content and water became the limited factors.

Abstract:Eight sediment cores collected with gravity corer and sediment profiles dug by handed-tools from the EBFZ marsh downstream of the Huolin River were studied with high-resolution distribut ion of heavy metal (Cu, Zn, Cr, Ni, Co, Pb, Fe, Mn), pH, TOC and TN.The results showed that Zn, Fe and Mn were inriched in the upper part of the sedimentary sequence and significantly correlated with TOC.On the contrary, heavy metal contents in most of the deeper layers of sediment cores were relatively lower and closed to geochemical background levels.Correlation between elements was easier to identify with high-resolution sampling.Heavy metal contents in the upper layers are higher in sediments that are closer to river and have high flooding frequency.

Abstract:Effects of temperature on characteristics of boron adsorption-desorption by Ca-montmorillonite, goethite and manganite were studied.The results showed that boron adsorption by Ca-montmorillonite increased with increasing temperature, whereas boron adsorption by goethite and manganite decreased as temperature rose.Boron adsorption-desorption by Ca-montmorillonite was less hysteretic as compared to goethite and manganite in terms of boron desorption rates at different temperatures.At constant temperature, boron adsorption heat for Ca-montmorillonite, goethite and manganite were 63.08, -122.45 and -93.91 kJmol^-1, respective desorption heat were -31.02, 53.95 and 46.30 kJmol^-1.The process of boron adsorption by Ca-montmorillonite was endothermic.By contrast, the process for goethite and manganite were exothermic.As temperature rose, boron reacted faster with minerals initially.However, the reaction rate as a whole slightly decreased.

Abstract:The dynamics of accumulation and disappearance of ⁹⁵Zr in six kinds of water-soil systems was studied by using isotope-tracer technology, and the fitting equation was confirmed by application of nonlinear regression method.The results showed.1.The specific activity of ⁹⁵Zr in water was reduced quickly in the beginning and then tended to slow down gradually.The descend velocity differed from one water-soil sys-tem to another.This indicated that the sludge of riverbed had strong capability of adsorption to ⁹⁵Zr which was as follows: panfan red soil> red-yellow earth> blue purple clay> paddy soil> sea mud> sand.2.The specific activity of ⁹⁵Zr in sludge of riverbed increased synchronously with time and reached a counter-balance after a period of time.The balancing time of different soils differed in the following order: red-yellow earth(13.10d) < panfan red soil(15.53d) < sand(15.64d) < blue purple clay(17.85d) < paddy soil (20.65d) < sea mud(21.46d); 3.The differentiation analysis(the determine coefficient r² and confidence interval) of the fitting equation of dynamics of accumulation and disappearance in each system indicated that each regression equation could describe the behavior process of ⁹⁵Zr in water and bottom soils more efficiently.

Abstract:The effect of cultivation and management on changes of soil fertility was investigated with pointing sampling at different periods at small catchment scale combined with long-term field experiment in a low hilly red soil region in subtropical China.The key driving force for changes of soil fert ility was analyzed, and the correlation models were set up between the changes of soil nutrients and the nutrient balance of various land use systems.The results showed that changes of soil nutrient contents coincide with that for nutrient balances.Soil organic matter content decreased in wastelands and paddy fields; soil available P and K contents increased when changing the wasteland into upland but decreased into mixed-forest land; and soil nutrient contents trend to rising after changing into paddy field.The changes of soil total N and available K correlated significantly with the balance of N and K in slopping upland systems.However, correlation appeared unmarkedly between soil available P and P balance, which was caused possibly by excluding soil fixation and decomposit ion processes in the calculation of P balance.

Abstract:The experiment was carried out in calcareous soil in Fengqiu Agriecological Experimental Station (Chinese Academy of Sciences).Organic fertilizer, inorganic fertilizer and organic fertilizer mat ching inorganic fert ilizer were used in fixed proportion(N 300 kg hm^-2, P₂O₅ 135 kg hm^-2, K₂O 300 kg hm^-2).After 10 year experiment, the content of total N, P, K and available N, P, K of soil were increased signif icantly under three fertilizing treatments.Compared with inorganic fertilizer treatment, organic fertilizer treatment had better effect on increasing the contents of total nitrogen and available nitrogen as well as the content of available P.However, there are no significant difference on the content of total potassium of soil among three treatments.The experiment results shown that it is more suitable way to match organic fert ilizer and inorganic fertilizer for increasing soil fertility.

Abstract:This paper outlines an approach to the logistic regression for early rice recommended fertilization in red soil area.Logistic Regression model are used to relate nitrogen fertilizer with soil fertility variables to predict the high yield probability.The comparison between Logistic model and existing quadratic model is given on paddy soil of the red soil area.

Abstract:The study on dissolution of potassium from feldspar powder by fermented broth and the metabolites of the strain NBT was carried out in shake flask.The results showed that K, Si, Al from feldspar was activated by fermented broth cultured for 48 hours.The contents of K, SiO₂, and Al₂O₃ in the fermented broth were 184.1, 39.8 and 12.6 mgL^-1 respectively after shaking with feldspar in it at 28 for 10 days and were 106.1%, 63.1% and 133.3% respectively over that the control of sterilized fermented broth; In addi tion, a lot of organic, ammonia acids and capsular polysaccharide were detected in the fermented broth.The shake flask study showed that the metabolites had the potential of dissolving the feldspar and the contents of K in the solution were 110.8 mgL^-1 for organic acids, 84.9 mgL^-1 for ammonia acids and 19.7 mgL^-1 for capsular polysaccharide.The effect of K release was increased by 62.2% by the mixed metabolites.The dissolution of feldspar was through the acid dissolution action and chelation of the metabolites.

Abstract:By use of the hardware of MIA-3 autoanalytical system, we developed a special software according to the need of research, and set up an autotitration system which can be used in constant pH, and tried to apply it to the telease process of surface hydroxyl of a latosol with great iron oxidex.The results conform that the quantities of hydroxyl released are affected by pH and the amount of SO₄^2- added in Na₂SO₄ solution, and that the dynamic changes of hydroxyl release accord with Elovich equations.

Abstract:土壤特性往往是沙质荒漠化的一个指征^[1],也是不同形式的土地沙质荒漠化导致的生态系统功能改变的一个非常重要的测度^[2]。粒度组成是土壤结构和生产力的重要方面。形状和大小各异的土壤颗粒组成的土壤结构表观上是一个不规则的几何形体。分形理论是描述不规则几何形体的有效方法^[3]。Turcotte^[4]提出的多孔介质材料的粒径分布公式中由于确定大于某一粒径颗粒数较难而在土壤分形研究中无法广泛使用。为此,杨培岭等^[5]提出了用粒径的重量分布代替数量分布来描述土壤分形的模型。吴承祯等^[6]用此模型对不同经营模式土壤团粒结构的分形特征的研究表明分形维数可以很好地反映土壤肥力特征。

Abstract:土壤分离过程是指在降雨溅击和径流冲刷作用下,土壤颗粒脱离土壤母质的过程^[1]。对因降雨溅击引起的土壤分离过程曾进行过深入系统的实验室模拟,但对因径流冲刷引起的土壤分离过程,并没有得到充分的研究[2]。实验水槽内的水流动力特性与坡面径流的水动力学特征十分相似,因而用变坡水槽可以对坡面流分离土壤过程的水动力学特征进行模拟。

Abstract:多环芳烃类化合物(PAHs)是由2个或多个苯环以不同方式聚合而成的一组有机污染物,它们在环境中稳定、持久,许多PAHs化合物属于美国环保局(U.S.EPA)的“优控污染物”,有的还具有“三致”(致癌、致畸、致突变)作用。PAHs在环境中无处不在,在城市污泥中也普遍检测到^[1～4](1)。城市污泥(简称污泥)是城市污水处理厂产生的亟待解决的城市固体废物。目前,污泥的处置方式主要有填埋、焚烧、倒海和农业利用等。农用资源化是城市污泥最有前景的处置方法,有利于城市和农业的可持续发展^[3]。

Abstract:土壤是环境系统中物质与能量交换的枢纽,土壤动物在土壤物质能量迁移转化过程中具有特殊的功能和作用。然而,随着人类活动对环境影响的加剧,原生植被受到破坏,各种污染物质不断在土壤中富集,对土壤动物的生存繁衍带来严重威胁,目前土壤动物学者的研究,主要集中在土壤动物在成长过程中的作用,理化性质的改良,土壤养分循环以及区系分类等,很少涉及土壤动物与环境特别是污染环境关系的研究。农药是目前主要的化学性环境污染物,农药污染对自然和农田生态系统的结构和功能都有影响^[1],有实验表明,农药污染对土壤动物新陈代谢及卵的数目和孵化能力有明显影响^[2,3]。