Abstract:The present paper deals with the soil classification in Ancient China.The historical development of the soil classification systems is summarized as follows:1.It was described is the book "Yu-kung" that following the floading control and river harness,a country-wide expedition of the soils had been carried out.The lands all over the country were divided into 9 regions according to the conditions of their eaploitatibn and utilization.At the same time.the soils were divided into 9 "soil types",each type subdivided into 3 grades and 9 sub-grades mainly on the basis of their fertility.2.It was recorded in the book "Chow-li" that the lands of the country were delimited into 5 "Soil Regions" in which the vegetation and animals were discribed.The delimitation of "Soil Regions" delimited mainly according to their topography was as follows:
(A) Mountain and Forest Landa
(B) River Plains and Depressions
(C) Hill Lands
(D) Upland and Coastal Lands
(E) Plain and Marshes
3.Aecording to the descriptibn in the book titled "Quan-sze",a more detailed soil classification system was developed on the basis of the "Soil Type" and "Soil Region" mentioned above.In this system,the soils were divided into 18 "Soil Groups",and subdivided into 90 "Sub-groups" acenrding to their utilization,vegetation and soil properties,including colour,texture,structure,prosity and ground water regime etc..From this stwdy,in may be concluded that the soil classification of Ancient China was developed mainly on the basis of the knowledge of "soil adaptation to vegetation",and it not only provided a favorable foundation for land utilization,but also was a splendid chapter in the history of development of soil science.

Abstract:The results of experiments and investigations on the symbiotic nitrogen fixation of soybeaa in lessive region in Heilongjiang Province are summarized as follows:1.In symbiotic system,the soybean modulation showed a high positive correlation with the plant growth.Under different ecological conditions,the divergency in the correlation increased with the increasing rate of nodulation.2.In the early stage of growth,nitrogen fertilizer showed sensitive inhibition effect on the nodulation for 20 soybean varieties,whereas phosphate fertilizer produced favorable effect on the growth,nodulation and the rate of nitrogen fixation of soybean.The application of phosphate fertilizer together with molybdate showed more favorable effect on the symbiotic system.3.The intensive decline of the plant growth,the rate of nodulation and the yield of the soybean were resulted by the continuous cropping of this crop.Applicaof phosphate and molybdate fertilizers,although improved the rate of nodulation and nitrogen fixation,could not correct the unfavourable effect resulted from continuous cropping.4.Under the condition of mechanized cultivation,a significant variation in the rate of natural nodulation of soybean appeared.In some fields,even no any symbiotic fization of nitrogen took place,and in a few fields,the rate of nitrogen fixation reaehed 50 per cent.The highest amount of fined nitrogen was about 0.33 kg/ha,with an average figure of 0.18 kg/ha from 15 scattered locations.

Abstract:The present map showa the general status of the potential of soil phosphate nutrition of China,including the content and composition of sail phosphorus and crop response to different phosphatic fertilizers.Besides,the phosphorite deposits suitable for the direct application in the form of powdered rook phosphate are marked on the map.It is found that the compositions of different forms of soil phosphorus are most closely related with the zonality of main soil groups.Sia types of the potential of phosphate nutrition are classified according to the composition of soil phosphorus.In the forest soils and meadow soils about 50-80 per cent of total phosphorus are presented in organic form.In large areas of the pedocal regions of China,soil phosphates mainly remain in forms of fluor-apatite and hydroxyl-apatite,and rich in total phosphorus,but their availability sometimes are low.In lateritic soils,red soils and yellow soils of southern China,these primary phosphate minerals have been highly weathered,and iron phosphates admixed with a very small amount of aluminium phosphates become the principle type of soil phosphate.However,the iron and aluminium phosphates in these soils are mostly coated by a film of collbidal iron oxide and formed occluded phospha.te,which can be only liberated under strongly reduced soil condition.Crystalline iron phosphate which has been proved unavailable to upland crops,however even in the form of strengite,shows high activity in paddy soils as in the case of amorphous iron phoaphate.Calcium,iron and aluminium phosphates all have been found in brown soils,drab soils and other soil types in the transitional zone,all of which range in pH 6.5-7.5,in general the soil phosphates is more available.It could be concluded that accordine to the composition and content of soil phosphate and crop response to phosphatic fertilizers,the potential of phosphorus nutri-tion of soils are obviously increased in order from the south to the north of China.The following legend is attached to this map.

Abstract:The present paper deals with preliminary study on the influence of the highly weathered coal on the colloidal properties of soils in Xinjiang.The results obtained are summarized as follows:1.The contents of organic and active humus in the weathered coal were higher than those in brown coal and peat,and the weathered coal was characterized.by a higher content of carboxyl and phenolic hydroxyl groups,a greater buffer capacity and a higher electrophoresis velocity.2.The results showed that organo-mineral complex was formed by the interaction of weathered coal applied and the clay in soil.The intensity of the organumineral complegation increased with increasing amount of weathered coal applied.The characteristics of the organo-mineral complex in the soil applied weathered coal were greater in buffer capacity,CEC and water holding capacity,higher in viscosity and lower in electrophoresis velocity and ultimate pH.From the results mentioned above,it is evident that the application of weathered coal may improve the soil and promote its fertility.

Abstract:Columns of loosely packed sandy soil of different heights were used in present investrgation.The salt movement in the soil columns was simulated with labelled NaI¹³¹.The columns were placed in a salt solution of labelled Na₂S³⁵O₄ (5 gm/l) simulating the ground water.The sail was exposed to evaporation.The movement of soluble salts in soil and solution were studied by radioidobopic method.Results obtained are anmmarized as follows:1) The content of soluble salts in soil phase rised with the capillary water during evaporation from soil surface.A higher concentration of salts appeared in the front of the capillary water.The thickness of salts concentrated layer increased following the continuous evaporation of soil water,and finally a layer of salt accumulation was formed in the surface soil.2) The soluble salts contained in water phase also moved upwards with the rising of capillary water.The rate of its movement,however,was lower than soil salts.But the continuous rise of capillary water also induced the sulphate se,lts accumulation in the surface of the soil column.3)Accordine to the results mentioned above,it is concluded that lowerine the ground water level below the critical depth is an effective measurement for the improvement of the saline soil.At the same time,it must be considered to incorporate with other practices such as leaching of salts by irrigation,leveling of the land and increase of the application of organic manure in the soils.

Abstract:Investigations of mercury fixation were carried out on the samples of red soils,black soils,yellow brown soils,loessial -suits and cultivated fluviogenic soils collected from different parts of China.The relationship between the content of mercury added to soil and fixed in soil might be eapreased by the following equation:m=acⁿ,where "m" denotes the amount of Hg fixed (μg/lg soil),"c" denotes concentration of added Hg (μg/lg soil);"a" is a constant;"n" is the exponential.We attributed this reaction to chemical fixation rather than biological,because of the greater reaction speed of its fixation.Owing to the capability of mercury fixation in soil,even in the soil severely polluted by the mercury,the content of mercury in upland crops grown on the polluted soil only ranged in a few ppb,much lower than the critical level of present sanitary regulation.But under the waterlogged condition,the fixed mercury of the paddy field is reduced into the available form and the brown rice appears mercury pollution.The fixation and release of mercury in soils were correlated to the types of soil.The factors influenced fixation and release of mercury are to be further studied.

Abstract:The buried boggy soil which is known as "dark earth" popularly are turned up and used as soil mulch in some saline soil region.It has been proved favorable to the improvement of saline soil.The results of laboratory study of its effect on the soil water movement are as follows:1.The dark-earth mulch depresses the upward movement of the capillary water in soil.Its favorable effect on the improvement of saline soil may be attributed to the good structure and more of larger non-capillary pore space of dark-earth.The dark-earth of larger pore apace and the underlying soil of fine pare space constitute a characteristic stratified systems of pore space iu soil,which induces the lower conductivity of soil water and reduces the rate of upward movement of ground-water.Maintenance of the effective dark-earth mulch,therefore,is a favorable measurement for the improvement of saline soil.2.The effectiveness of dark-earth mulch decreased with the rising of ground-water table.Lowerine the around-water table mieht promote the effect of dark-earth on improvement of saline soil.3.In order to maintain the favorable effect of the dark-earth mulch,a thick effestive dark-earth mulch deeper than the ploughing depth is necessary.

Abstract:Large areas of sandy soil,approximately occupied 30% of the total arable land,are distributed over Xuzhou District,Jiangsu Province.A compact soil surface layer is always developed due to the settling of the coarse particles brought by irrigation water.The compact and sandy surface soil contains low organic and plant The improvement of this soil by the application of green manures-turning over of single cropping of vetch or mined cropping of vetch and rye grass,or manuring mixed with clay-was investigated.The results obtained from pot and field eaperimenu are smmmarized as follows:1.The effect of manuring of the mig-cropped vetch-rye grass was superior to that of single vetch on the increase of crop yield,but manuring mined with clay was the most effective.2.The holding capacity of the sandy soil for organic matter was increased with application of clay,and at the same time,mineralization of organic matter was decreased.3.Application of clay and turning over of green manures effectively improved the physical and chemical properties of sandy soil,provided favorable conditions for the formation of organic-mineral complex of the soil.

Abstract:Changes of the physical properties of a red soil (oaidsol) undergoing cultivation were observed.The soil is located on the rolling Iand in Ju-Xian county,western Zhejiang province.Field observation reveals that the red soil,once cultivated,usually appeares a friable surface layer which reduces the rate of evaporation of soil water,accelerates the restoration of soil moisture over night,and keeps the soil temperature in a warmer condition in winter.These effects may improve the soil physical condition for better crop growth.On the other hand,cultivation may alas encourage soil erosion in raining season and accelerates the evaporation of soil water in dry summer.Micro-aggregates of red soil seem to afford a better condition of soil fertility.Increasing of micro-aggregates,ranging 0.05-0.01 mm in diameter,oecurres in surface soil as cultivation proceeded.These aggregates,however,become dispersed under water flooded condition as in the case of paddy field.The improvement of physical condition of paddy soil can be accomplished by the application of manures.

Abstract:A puddling and soft cultivated layer of soil is always the favorable soil physical condition for the high yield rice in growmg stage,and after the middle stage of rice growth a more compact and hard soil condition is required for its better growth.The field study showed that the soil physical condition-puddling,softness,compact and hardness required by rice in different growing periods had its own characteristics.The hardness of paddy soil in relation to different soil texture,organic and rice roots was also studied.Results obtained denoted that the effect of soil texture on the a}oil hardness was more important than that of soil organic matter.A simulation test showed that when flooding after plough and harrow,the dynamic change of the soil hardness appeared firstly a high level,then decreased with the duration of submergence,and at last tended to a stable level.

Abstract:This article deals with the effect of different structure on the phosphorus figation and nitrogen retention in some red soils.According to the results of the ezperiwent,the relationship between the soil structure and the its nutrients supply and retention is discussed.Experiment results showed that the well-cultivated upland red soil and the fertile paddy soil of red earth with better structure were lower in fixation and higher in supply capability of phosphorus as compared with the infertile upland red soil and paddy soil of red earth with poor structure respectively.The NH₄-N retention in well-cultivated upland red soil with better structure was more in quantity than that in the infertile upland red soil with poor structure and nitrogen in the former released more readily than that in the latter.

Abstract:Rain water was collected from three different places of Zhejiang province in the period from Jan.to Dec.in 1976.The content of N,P,K and S were analysed.The results were as follows: