Abstract:The association and chemical composition of clay mineral and cation exchange properties of 20 soil horizons in 7 soil profiles on the south slop of the Dabie Mountains in Hubei Province were studied.The results indicated that:1).the 14Å minerals and kaolinite were the main clay minerals in the soils examined,and the secondary was illite.The 14Å clay mineral of soil on the feet of mountains was vermiculite.The content of vermiculite decreased whereas the content of 14Å intergrade mineral in soils increased with the rising of the altitude.The chlorite was found in the middle and upper parts of the mountains.And with an rising of the altitude,the content of kaolinite decreased slightly but the degree of crystalinity was enhanced and the content of illite increased as well as a small ammount of 12Å interstratified mineral was found.2).the gibbsite was found in the subsoil at an altitude of 920m,then it not only was found in all horizons of soil profiles but also its ammount increased as the elevation was going up.3).the chemical composition of soil clay fraction,even the surface chemical properties varied with the rising of altitude,which was quite agreeable to the change of clay minerals.4).between the 14Å clay minerals,vermiculite and 14th intergrade mineral in soils,there were apparent differences in their CEC,pH value and the ammount of exchangeable aluminum.The methods for identification of these minerals and the formation of gibbsite are discussed.

Abstract:The present work is a part of the cooperative project between Northwesters Agricultural University Shaanxi,China and Justus Liebig University,Gissen,W.Germany.The content and variation of nonexchangeable ammonium in manured loessial soil and its availability for winter wheat were studied through a common plot experiment and a micro plot experiment using 15N-labelled ammonium under field condition during wheat growing period.The experimental results showed that manured loessial soil possessed a greater reserve of nonexch-angeable ammonium;in the cultivated layer of 0-20 cm of the soil tested,the nonexchangeable ammonium amounted to 236 ppm N,constituting about 23% of the total N,and in the soil layer of 0-75 cm,it was 252 ppm N on average,constituting a quarter of the total N.Both the newly fixed ammonium and the ammonium oringinally fixed by soil played an imortant role in wheat growth;the former was predominated by its higher availability,while the latter was cheristerized by its greater quantity.The maximume net release (MNR) rate of newly fixed amonium ranged from 38.0 to 70.5% in the soil layer of 0-75 cm,being much higher than that of the ammonium oringinally fixed by soil that ranged from 10.4 to 22.2% in the same soil layer.Howerver,the MNR amount of the ammonium oringinally fixed by soil was 12-72 ppm in the soil layer of 0-75 cm,it is much more than that of the newly fixed ammonium that was only 7.4-10.9 ppm in the same soil layer.It was also proved that the fixation of ammonium by clay minerals in manured loessial soil could act as a pool of N in soil and applying N tended to increase the nonexchangeable ammonium in soil.

Abstract:The error of estimates of soil water content in field can be devided into three components,i.e.that of location,ealibration,and instrument.The analysis of variance of measurements at 5 locations in a wheat field represents that location component is the main source of error most of conditions.The contributions of calibration variance and of instrument variance to total variance are relatively high when the error (CV) is low even the instrument variance is at a very low degree(10^-6(cm³/cm³²).The results of the neutron probe measurements are similar to that of the triditional oven dry method,while errors (CV) of the former are smaller than that of the latter.Therefore,this method should be reliable.In addition to easy and fast to be controlled,this method should be accepted as a effective tool for monitoring soil miosture in field conditions.

Abstract:With a limited area,podzolie soils in China are only found in the northern part of the Da Hinggan Mts.and in the vertical sequence of mountain lands on the Qinghai-Xizang Plateau.The podzolic soils which are derived from sandy parent materials and formed under coniferous forests in cool temperate climate with a main soil forming process resulted from the ehelation,eluviation and illuviation of humic acid are characterized by (1) chelation,eluviation and illuviation of humic acids,(2) enrichment of SiO2,(3) strongly acid reaction and eluviation-illuviation of Fe and Al,(4) breakdown and differentiation of clay minerals,and (5) unique mieromorphological features.According to the criteria of the Keys to Soil Taxonomy of U.S.A.,the podzolic soils in China are tentatively sorted into Alfisols under which they are subdivided into two great groups,i.e.Lithic cryoboralf and Classic cryoboralf.The former is spread in the Da Hinggan Mts.north of latitude 500N and the latter is dis9ributed mainly on the Xizang Plateau with an altitude of 4000 m.These soil regions are important production bases of coniferous forests of China,and are of great significance for the development of forestry and the protection of ecological environment.There are some divergences of views on the classification of podzolic soils among in China and other countries and much work remains to be done in this respect.

Abstract:Filed observation for water balance in upland red earth of Central Yunnan Plateau was made using self-made evapotranspiration-permeameter in 1983-1985.Data obtained showed that (1) the results obtained by the evapotranpiration-permeameter were quite consistent with the data of the Hydrologicalstation in the same period,with proved that the self-made evapotranspiration-permeameter is highly precise,Convenient for operation,(2) soil mulching study gave very good results for both iutrase soil water retention and crop yield.

Abstract:In this paper,395 soil profiles collected from coastal region of Jiangsu at different seasons were studied,on the basis of the analysed data of 2089 samples of different horizons,dynamic regime of salts in soils were revealed as fofollows:(1) The features of sea beach soil salinization process are that the salt distributed in profile are in the shape of cylinder,"T" or "Y",with an average salt content of >0.7%;and in a state of salinization that water end salt move upward in whole year.The features of desalinization process are that the salts distributed in profiles are in the shape of pagoda,or sometimes of "T" during dry season,with an average salt content of ≤0.6%,and main dynamic regime of salts is going downwards with water.(2) It has been found there is a singnificant line between beach of meadow and that of Suaeda salsa,above which the desalinization process oceurs and below which the salinization process is going on.(3) Due to strict sequential development of eco-nvironmeat of tidal belt varying with topography and frequency of tidal intrusion,sea beach soils have significant regularity of distribution in belts.

Abstract:红砂岩、红色砂砾岩发育的土壤占江西省总土地面积的10%,其中红砂岩红壤1780万亩,红砂泥土和沙泥田486万亩。主要分布在海拔30-300米的低丘陵岗地,植被以稀疏马尾松、禾本科草类为主,部分丘岗中下部和平缓岗顶已经耕垦利用,垦殖指数为23%。其中,长期种稻的形成红沙泥田、轮作方式多为绿肥-稻-稻或油-稻-稻;种桔、茶、旱粮的发育为红沙泥土,主要复种类型是花生、油菜或春大豆、芝麻(红薯),还有的种柑桔、茶叶等多年生作物。

Abstract:四川盆地遂宁组紫色土广泛地分布于盆地中部,也零星出现在盆地边缘。母质为侏罗纪厚层泥、页岩的风化产物。物理风化强烈,土壤水分状况不良,耐旱力较差,在一定程度上限制了土壤生产力的进一步发挥。本文系四川盆地遂宁组不同质地紫色土的持水特性的初步研究结果,简报如下。

Abstract:钴是维生素B₁₂的重要组成部分。反刍动物缺钴时出现贫血、消瘦、厌食症状,严重时可导致死亡。存在于自然界的甲基钴胺素类是环境中汞、锡等重金属元素甲基化的甲基供体。钴是生物固氮的必需元素,对某些作物具有提高产量和改善品质的作用。世界土壤缺钻极普遍,最近,杨琢梧等^[2]报道四川省进口牛羊由于缺钻而不能很好地生长发育,甚至死亡。本文报道我国一些典型土壤的全钻含量和分布及其影响土壤全钻含最的因素。

Abstract:Pot experiments using barley and ryegrass on 12 soils with different textures,organic matter,total nitrogen contents and C:N ratios were conducted and mineralized and mineralizible nitrogen in soils were determined by different methods in order to investigate the relationship between nitrogen uptake by plants and nitrogen in soils determined.The results obtained showed that N uptake by plants was well correlated with NO₃-N in soils extracted either by saturated CaSO₄ or KCl,but less correlated with NH₄⁺-N while the soils N mineralized after a 2-week aerobic incubation was closely related to plant uptake nitrogen,the soils N mineralized after a l-week waterlogged incubation did not reflect the nitrogen supplying capacities of the soils in non-waterlogged condition.The soil N released by boiling KCl was found to be highly correlated with the N in plants,and also with the soil N mineraized after aerobic incubation.Both aerobic incubation and boiling KCl method have the same value in evaluation of soil nitrogen supplying capacities.

Abstract:Potexperiment was carried out for studying interaction between P and Zn of soil and their nutrition of corn seedlings,grown on Calcareous Cinnamon Soil of Shanxi,which was loamy in texture with a pH of 8.12,available P of 2.56 ppm and available Zn of 1.08 ppm.At the same time,mathematic modelling was used in order to quantitively study the interaction of P and Zn in Calcareous Soil and their mutual effects on corn growth.The main results obtained are summarized as follows:(1) When the supplies of available P and Zn in soil were harmony,the uptake of F and Zn by corn seedlings were accelerated each other and the interaction between P and Zn was significant and vice versa.(2) The P application could accelerat the desorption of zinc and increased the content of available soil Zn.(3) The precipitation of Zn₃(PO₁)₃ in soil wasn't the main cause of Zn and P deficiences.The mutual restraint of P and Zn in corn nutrition was a kind of physiological obstruction within roots.which was caused by imblance of nutrition.

Abstract:The artificial forests existing in southern subtropical China consist chiefly of China fir and pines.Continuous reforestation of coniferous trees has resulted in the deterioration of soil conditions and decreased the production of forestry.For improvement of the forest soil and production of forestry,a three-year location experiment on material cycling of the establishing artificial forests of Cunninghamia lanceolata,Pinus massoniana,Schima wallichii and Eryahro-phloeum tordii on lateritic red earth in Nanning was conducted.Results of the experiment showed that the four types of forest trees differed from each other both in characteristics of biological material cycling and in amounts of litter.The mean annual amount of litter of coniferous trees was less than 4t/ha,whereas that of broadleaf trees such as Schima wallichii and EryzhropTzloes,m,fordii was more than 6.3 t/ha.In litter coniferous trees,Ca,Mg and Si as its essential nutrient elements,made up 60-80% of total ash,these elements being usually no Hacking in soil itself,while the litter of broadleaf trees conrained considerable amounts of N,P and K in addition to Ca,Mg and Si.Each year,China fir returned to the soil 118.5 kg of ash and,nitrogen per hectare in the form of litter,Pinup massoniana 79.5 kg/ha,Schima wallichii 168.1 kg/ha,and Erythrophloeum fordii 304.8 kg/ha.

Abstract:Twelve soils derived respectively from basalt,granite and marine deposit in the western parts of Guangdong Province were collected and for planting grass (Coastcross-1 Bermuda grass) in the greenhouse.Magnesium deficiency symptoms with chlorotie spots appeared in grass growing in the soils derived from granite and marine deposit,and plants responded well to magnesium fertilizer.Grass growing in soils derived from basalt showed no symptoms of magnesium deficiency,and did not respond to magnesium fertilizer.Incipient symptoms of magnesium deficiency appeared when the grass contained 0.15% Mg or less.Magnesium fertilizer had no strong influence on N,P and K concentration in the grass.But in magnesium deficient soils it made the grass grow well and increased the total N,P and K uptake of the grass significantly.

Abstract:In this paper,a simple method for simultaneous determination of exchangeable acidity and exchangeable alkalinity of soils which could distinguish to Na-exchangeable acidity,Ba-exchaogeable acidity,SO₄-exchangeable alkalinity and F-exchangeable alkalinity was proposed.The exchangeable acidity and exchangeable alkalinity of various red soils derived from different parent materials in South China were determined with the proposed method in the field.The results showed that acid red soils contained not only large amount of exchangeable acid but also considerable quantities of exchangeable alkali.Because Ba²⁺ ions possess a stronger power than Na⁺ ions in replacing exchangeable aluminium ions,which are the principal cause of soil acidity,the amount of Ba-exchangeable acid was larger than that of Na-exchangeable acid.Likewise,because the amount of OH^- ions released by ligand exchange between F^- ions and hydroxyl groups on the surface of soil particles was higher than that when SO₄^2- ions were used,the amount of F-exchangeable alkali was larger than that of SO₄-exchangeable alkali.For the same type of soil,the amounts of exchangeable alkali of red soils derived from acid parent materials were higher than that of the soils derived from basic rocks.The amounts of exchangeable acidity and exchangeable alkalinity increased with the increase in neutral salt concentration up to 0.1 N,and then approached a constant value.

Abstract:Dark brown forest soil was treated with radioactive aqueous solution of ⁷⁵SeO₃ at rate of 0.131 ppm and 1.631 ppm.Wheat was planted on the soil contained Se of 0.023 ppm and 0.493 ppm respectely.After the wheat being havested,residual ⁷⁵Se in the soil was fractioned by various extractants.Various forms ⁷⁵Se in the soil were in the order of isotopically exchangeable Se>that extracted by NH₄OH>extracted by HCl>that water soluble>that extracted by K₂SO₄·⁷⁵Se in the soil was present mainly as the form exchanged by NaHSeO₃.This fraction of Se constituted 28% of the total Se in soil,that extracted by NH,OH 20%;that soluble in water,6-7%.Most of ⁷⁵Se being in the form of SeO₃^2- added to the soil was quickly adsorbed by the soil.The results of the experiments also indicated that more than 90% of soluble Se was transformed into insoluble forms including organic Se and inorganic Se in the form of the SeO₃^2- In addition,the SeO₃^2- may also be reduced to Se⁰ and Selenides.Thus the availability of Se for plants was reduced.Content of Se in wheat have a directly correlated to that in the soil.It is suggested that to raise soluble Se in the soil is an important practice for increasing Se in wheat.

Abstract:This paper deals with the distribution of organic phosphorus compamds in organo-mineral complexes of periodically waterlogged paddy soils developed on red earth and paddy soils developed on facusrrioe deposits with various fertility in Zhejiang province.The results are summarized as follows:1.The organic phosphorus content in organo-mineral complexes were G₂>G₁>G₀.The C/Pe_org and N/P_org ratios of G₂ were higher than those of G_o and G₁,which reveals that the organic phosphorus accumulated in G₂ of organo-mineral complex is less than organic carbon and nitrogen.2.The total amount of organic phosphorus compounds extracted from organ-mineral complexes was higher than that in soil sample.For different compounds,inositol-P nucleic acid-P and phospholipid-P were 12.1-32.3%,1.9-5.8% and 0.7-3.1% of total organic phosphorus respectively.The contents of inositol-P,nucleic acid-P and phospholipid-P in G,were higher than those in G₁ and G_o.3.The labile organic phosphorus in organo-mineral complexes constitutes 5.0-15.9%,the moderately labiele 36.6-68.6%,the moderately resistant 13.0-26.0% and the highly resistant 10.0-29.3%.Although the percentage of labile pool in Go fraction was higher than soil sample,it dropped in G₁ and G₂.The results show that the distribution of labile and moderately labile pool in organo-mineral complexes of different soils is related to the contents of nucleic acid-P and inositol-P.