Abstract:A modelling soil column experiment was made to study the influence of soil water regime on the eluviation and illuviation of mineral elements in soil and its relation to the growth of rice and wheat.The conclusions are as follows:1.After submerging,the mineral elements were mobilized,causing an increase in concentration of these elements in soil solution,particularly in iron and manganese.The mineral elements were subject to eluviation.The amount of the elements accumulated and eluviated showed a sequence of Fe> Ca,SiO₂> K> Al,P,Mn,Mg.2.The liner regression equations showed that the main factors affecting the mobilization and eluviation of elements were percolation of water and soil Eh in nce growing season 3.The results of principal component analysis revealed that the mam soil genetic processes in early stage of submergence were activation and eluviation of mineral elements,relative accumulation of silica and aluminium and increase of soil nutrients.4.Although the soil was submerged only one year,the differentiation of Fe and Mn in profile had already appeared.Fe and Mn were eluviated in surface layer,illuviated in the middle of profile.5.The experiment results proved that water regime affected the growth of rice and wheat the permeable soil column (water percolation during the rice growing season being about 15 mm per day,and ground water table being controlled at 70-80 cm during the wheat growing season) was favorable for the growth of rice and wheat.

Abstract:The amount of water-soluble organic substances varied with the kinds of green manure,soil types and incubation time.The water-soluble organic substances of decomposition products of green manure were the substances with lower molecular weight,different charges (positive and negative) and isoelectric points,containing carboxyl and amino groups.Some of these properties changed with time duration of incubation.These organic substances were the products derived from the interaction between organic and inorganic constituents (chiefly iron oxides) of soil.In the soils rich in organic matter,these substances could determine the redox potential of the system where they existed,and there was a good negative correlation between them.The appearance of Cr⁺³ resulted from the influence of organic substances (as the source of electron) on Cr⁺⁶.The reducing capacity of such decomposition products for astragalus was stronger than that for rice straw.

Abstract:The Mössbauer spectra at ambient temperature and 80 K of ⁵⁷Fe-humic acid complexes,of which were centrifuged or electrodialyzed,were recorded respectively,and the nature of Fe³⁺,Fe²⁺ bound with humic acid at different pH values was studied.The Mössbauer spectra and parameters of ⁵⁷Fe-humic acid slurry at pH 3 fitted by computer show that three doublets(Fig.1 AA',BB",CC') are reasonable.The Fe³⁺ in the humic acid at pH 3.0 occurs in more than one type of enviroment and high spin forms.The Mussbauer spectrum signal for Fe³⁺ was observed but not for Fe²⁺ in the ⁵⁷Fe-humic acid at pH 1.0.59% of iron doped was detected in the decantate at pH 1.0.It showed that considerable proportion of Fe³⁺ was reduced to Fe²⁺ by humic acid at pH 1.0,but no Fe²⁺ bound with humic acid strongly.The Mössbauer spectra for Fe³⁺,Fe²⁺ were found in the ⁵⁷Fe-humic acid samples (pH 2.8) which were electrodialyzed at 30 V.This indicates that a part of Fe³⁺ is reduced to Fe²⁺.Owing to the decrease of pH of ⁵⁷Fe-humic acid complexes suspension in the process of electrodialysis,considerable proportion of Fe²⁺ was bound with humic acid at pH 2.8 strongly.According to Mössbauer spectra recorded at 80 K,there is evidence for magneticallyordered component in the range of the pH 1-3 but no evidence for that at ambient temperature.

Abstract:Chemical composition of saturated solution of phosphate fertilisers commonly used in China have been evaluated.The data indicate that saturated solution of super phosphate (OSP) is a strong acid (pH=2.47) solution with high concentration of P(4650 ppm),accompanied.with certain Ca²⁺,Mg²⁺,K⁺,Fe²⁺,and Mn²⁺.The saturated solution of AP is a neutral solution (pH=7.44) with a concentration of P higher than OSP by 1-2 times (11,600 ppm-P).However,the solution of saturated serpentine phosphate (Ca-Mg-P) is an alkaline solution (pH=9.66) with very low concentration of P (less than 3 ppm).There is a strong effect of P-fertilizers on the pH of soil adjacent to the granule applird.OSP decreased the pH of all soils tested,Ca-Mg-P,however,increased the pH of all soils samples,on the other hand,AP increased the pH of neutral and acid soils but decreased the pH of the loess soils.ΔpH value (positive or negative) and the volume of soil affected by P-fertilizer depend on the soil texture,buffer capacity,and the initial pH difference between the saturated solution of P fertilizer and soil.In general,the heavier texture and the less initial pH difference resulting in the smaller ΔpH value and volume of soil affected,and vice versa.

Abstract:Thy fertility status of three paddy soils (permeable paddy soil,paddy soil and that on meadow soil) were studied.Compared with the results of upland milar origin the following differences were observed.1.Condensation of humus was weaker.2.Amount of different fractions of microaggregates<10 μm were dereased.3.Contents Of C,N,P,were moderately decreased from fine to coarse fractions of microaggregates.4.Adsorption and desorption of P and NH⁴⁺ by microaggregates were stronger.5.Water retention capacity was higher and water permeability was lower.It has been proved that the different fractions of microaggregates<10μm in both paddy soils and upland soil developed from organic soil contained more humus are the main parts influening fertility,while the different fractions of microaggregates>10 μm in both paddy soils and upland soils developed from brown earth containing less humus are the main parts influening fertility.

Abstract:The mumbers of bacteria,actinomycetes and fungi,the dominant species of the sporebacteria,fungi and aerobic cellulose decomposing bacteria,and the activity of catalase,invercase,urease,the respiration activity and the rate of decomposing cellulose,and tlie biological antagonism of azotobacter in albic soil (baijiangtu) before or under cultivation were studied.Results obtained showed that application of a large amount of organic manure in combination with chemical fertilizers in sub-surface horizon of the soil could activate the biological activity in that horizon and improve its poor properties.

Abstract:The formation and development of paddy soils in Zhujiang Delta is close related with the deposition and formation of the delta; with the enbankment beach land for planting rice,the soils is still under the condition of saliniiation and swamping,due to high salty ground-water table,and the swamping paddy soils are formed.Following the raising of land surfacc of polder fields and the lowering of the ground-water table,the eluviation-illuviation processes are weaker and plowpan is formed; thus the guyed paddy soils are formed.Through long term warping and applying muddy manure,the soil surface is further raised and the ground-water table is greatly lowered,the eluviation-illuviation processes are intensified; the periodically submergic paddy soils are formed.Of course,this is only the rough description of the formation processes on the delta,the human activity and cultivation practice are greatly affect the formation and fertility of the soils.

Abstract:The Dupang Mountain is located at 25°09'-25°50'N,111°17'-111°51'E in Hunan.The soil formation in this region is characterized by stronger desilicification and allitization,with clay minerals dominated by kaolinite in B horizon,a lower silica-alumina ratio being generally below 2.5,a higher organic matter content and a strong eluviation in the soils on the upper part of vertical sequence.With distinct zonality,the vertical sequence of soil distribution from the upper part downwards is in the order of mountain red earth (below 700 m)-mountain yellow earth (700-1550m)-mountain yellow-brown earth (1550-1950 m)-mountain shrubby-medow soil(>1950 m).Mountain yellow earth is of most importance in the soil sequence,of which the properties indicate that yellow earth is not the early stage in development of and earth,but has its own genetic characteristics.Humid climate,better permeability of weathering materials are all the condition favorable for the formation of yellow earth.

Abstract:Yellow loessial soils are infant soils developed on lossial material,without distinct development of genetic horizons and aonal characteristics of profile.The soils are similar to their parent material.The profile pattern is mainly composed of horizons of A_p-C or A-C.Based the diegnostic horizon and profile,the soils are divided into two subgroups,i.e.primary yellow cultivated loessial soils and Lightly yellow cultivated lossial soil.Based on the hydrothermal regimes of the soil in crop growing season (April to Sept.),the soils are subdivided into such soil families as warm-moist,warm-irrigated,warm-wet,warm-dry,cool-moist yellow cultivated lossial soils etc.Based on the texture and O.M.content,the soils are further subdivided into 28 soil species.The soil are mainly distributed in northern Shaanxi with an altitude of lower then 1200 m.

Abstract:With the visible-infra-red multispectral scanned images and the scanned day and night thermal images,the soil albedo image and the day-night thermal image can be done.With a few soil thermal inertia data measured in laboratory,the corresponding soil albedo and day-night temperature difference were measured synchronously in fields,through dualistic regression,a dualistic cubic formula was obtained.Using this equation and the soil albedo image and the soil temperature difference image,a soil thermal inertia image was obtained.Then the soil thermal inertia image was transformed into a soil moisture map,with the aid of regressing the soil thermal inertia to the coil moisture.The error of the soil moisture map ranged from -4.18% to 1.98%,the mean absolute value of the errors was 1.85%.

Abstract:The crystallization of salts in three kinds of saline soil was studied,with polarizing microscope and of scanning electron microscope (SEM).It was found that the crystallization order depended on temperature,and under different temperature the main salts in soil solution were determined rapidly.The morphology of several salts in soil were studied by SEM Technique.It was found that halite (NaCl) Pras closely cemented with soil particles,thenardite (Na₂SO₄) was transformed from mirabilite (Na₂SO₄·10H₂O) by dehydration,and the glaubcrite [Na₂Ca(SO₄)₂] was formed by calcium sulfate and sodium sulfate.These salt crystals separated were clear,without any mixture.They would be formed in complex salt under certain conditions.As an example,the condition which affected the transformation of mirabilite-thenardite and its effect on the development of soil structure are discussed.

Abstract:This paper presents the comparison of the preparation methods of plant tissue for electron microprobe x-ray analyzer.It has been shown that epidermis and cortex of maiu root were apparently shriveled with air drying method.Large amount of K and Ca were removed out of the root prefixed for 1 hour with 4% glucaraldehyde.Only with freezinglrying technique at about 5×10^-4 Torr and below -800C,could the morphology of the sample obtained be kept in original feature and elements be kept in situ;besides,this method was high in efficiency.Results obtained from the samples prepared with this method and investigated by electron microprobe showed that a considerable amount of K was detected within the cells of cortex and endodermis and an eVen larger amount of K was concentrated in the stele.But Ca was accuntulated in the cortex and the endodermis and little was found in the conducting tissue of root.A rather high concentration of Si was also observed in,the tissues outside the endodermis of the root.This indicates that soil particles enter the root and thus the endorhizosphere is formed after the cells of the epidermis and the cortex have been destroyed by the soil microbes.

Abstract:土壤中许多重金属元素含量超过某一限定指标后,常对生物和人体构成潜在毒性,故世界各国都非常重视土壤环境背景值和重金属元素控制指标的研究^[1,7,8]。本文对辽河平原土壤中铅、锌、铜、锡、镍、铬、汞、砷等8种金属元素含量与土壤成土条件的关系做了粗 浅的分析讨论。