Abstract:The effect of turnover of farm-manure,green-manure,wheat straw and mixed application of 1/2 green-manure and 1/2 wheat straw into soil on soil fertility in the rotation of winter wheat and corn in Shangdong Province was studied.Experiment showed that these manuring measures not only increased total amount of organic matter,but also improved its quality,and the stability of aggregates and nutrient condition in the soil.For the aggregates in diameter from 0.25mm to 3.0 mm,the total content of organic matter increased with the increase in size of aggregates.The proportion of Gl fraction of the complexes tended to increase,while the proportion of G₂ fraction tended to decrease with the increase in size of aggregates.The G₁/G₂ ratio was getting increased with the increase in size of aggregates.

Abstract:Six main purplish parent materials of soil in Sichuan basin have been studied by chemical,physical,differential thermal,X-ray and micromorphological analysis and pot culture. Results obtained are as follows:1.The difference in SiO₂/RiO₃ ratio of the clay minerals among the soils derived on purple parent material,parent material and rock is insignificant.There are irregular lithorelicts in both soil and its parent material.Microaggregates are poorly developed in the soil.All these indicate the feature of purple soil characterized by the profile of A-C pattern and being young skeleton soil.

Abstract:The present paper deals with the effect of intensity of weathering process during soil formation on the composition,distribution and transformation of phosphorus of various soil types fractions of soil particle sizes in soil types of China.Studies indicated that the higher the weathering degree of the soil,the greater the relative contents of total phosphorus,available phosphorus and organic phosphorus in clay.For example,the total phosphorus in clay fraction was five times as much as that in sand fraction of latosol,while this ratio fell below two in dark loessial soil which was more weakly weathered compared with the former.It was also showed that the forms and distribution of inorganic phosphate were also affected by the weathering process.In dark loessial soil the occluded phosphate might be up 47% of total inorganic phosphate in clay fraction,far higher than that in the original soil.

Abstract:Four group of water-stable microaggregate were separated from calcareous soils by means of three colloidal-dispersing methods.They are the group dispersed by sodium (GI₁),the group dispersed by decalcification (GI₂),the group dispersed by grinding (GII) and the group dispersed by water.The contents of humus,fulvic acid and clay mineral in these four groups showed a tendency as follows:GII>GI₂>GI₁Go.The content of microaggregate<10 μ in four groups is positively correlated with the contents of particles<10 μ,CaCO₃ and in soil.

Abstract:The present paper deals with the surface properties of some iron oxides by means of the equilibrium of iron oxides with 0.01N NH₄Cl solution.The results showed that surface charge of iron oxide was closely related with the pH.Positive charge of iron oxides (represented by Cl^- ion adsorbed) was significantly negatively correlated with the pH,but negafive charge (represented by NH₄⁺ ion adsorbed) was positively correlated with the pH.For synthetic iron oxides,the zero point of charge (ZPC) obtained when the adsorption capacity of counterions was equal to zero approximated that obtained from the potentiometric titration.Basic property of surface hydroxyl of iron oxide showed buffering effect on the H⁺ ions in acid NH₄Cl solution.

Abstract:An oxygen sensor was inserted directly into the soil for the determination of oxygen content in paddy soils.The rate of chemical consumption of oxygen in the soil was related to the reduction intensity of the reductant.The rate was faster for organic reducing substances and sulfide,requiring 20-30 minutes for the attainment of a steady state.The reaction for ferrous iron required 2-3 hours.The reaction rate with manganous ions was the slowest, even when a large amount of Mn²⁺ was added to the soil.The change in oxidation-reduction potential followed that of the oxygen content,with an abrupt fall to lower than 100 mV when the oxygen content decreased to less than 1-2 mg/1.

Abstract:This paper deals mainly with the soil forming process and genetic properties of the allitic soils in China.(1)Based on the data of the macro and micro-morphological characteristics,the fertility properties and other synthetic indicative features,various diagnostic horizons and their structural patterns relating to the different soil categories have preliminarily been established and distinguished. (2)By using of the results mentioned above,the new genetic and morphological classification principles for the allitic soils were suggested.The principles include three main aspects,i.e.the geographical genesis factors,the soil properties and morphological features, the soil forming process and its conditions,which provide the basis for the systematic and automatic classification for the allitic soils in China.

Abstract:Unsupervised and supervised classification of soils of an arid area in Xingjiang was made using landsat data which were derived from scanning of the images on a transparent negative hard-copy and processed by micro-computer.The map compiled from these data is on a scale of 1:400,000 and covers an area of 12,375 km².Before classification,the scanned data of the four channels were matched by columns and rows according to some special topographic fertures on the image.All anomalous data were rectified by the methods designed by the author.For the unsupervised classification,the key tactics adopted by the author was firstly to find out and fixed the suitable number for the division of soil groups in this region, and then to select the proper parameters in order that the iteration could be continued freely until satisfied results were obtained.

Abstract:An investigation was made on the relationship between the spectral reflectivity of different field soil humidities on yellow brown earth and the spectral reflectivity of ovendried soil samples using the data in the waveband of 410-1000 nm.Experimental results showed that this relationship followed the first order regression equation.Meanwhile, the relationship between soil spectral reflectivities at four wavelengths and soil hnmidities was also studied,and it was showed that the relationship followed the second order regcession equation.On the basis of the experiments their varying characteristics and the significance of its application in remote sensing are briefly discussed.

Abstract:Based on the data of artificial rain obtained from 42 experimental plots on the different eroded soils including red earths derved from quaternary red clay and granite and puple soils in Xingguo County of Jiangxi Province,the equations,W=aT^b,V =aT^b and M=(a+b/T)^-1, were established by curve-fitting method to give expression to the relationship between raining duration and runoff coefficient,infiltration time and its rate,and infiltration time and its capacity.These equations are of practical significance for revealing the characteristics of runoff and permeability,estimating the amount of runoff and loss of soil by erosion and evalusting the beneficial effect of soil conservation.

Abstract:This paper reported the result of eight rare-earth elements (REE) in 29 cultivated fluvo-aquic soil samples collected from Tianjin region determined by instrumental neutron activation analysis.Although the recent alluvial deposits on which these soils were derived as their parent materials were different in their origins,the patterns of REE rnntent and distribution of 29 soil samples were quite similar.In comparision with the three heavy REE (Tb,Yb,Lu),the five light REE (La,Ce,Nd,Sm,Eu) tended to be enriched and concentrated in the clay fraction(<0.005 mm) of the soil in the processes of weathering and soil formation.

Abstract:本文主要探讨P、K、Ca、Mg、Fe、B、Mo、Mn、Zn、Cu等10种元素对红萍生长、固氮作用及无机成分含量的影响,以及缺素临界指标,以便对红萍的缺素诊断及合理施肥提供依据.