Abstract:1. Сущность мелиорации засоленных почв посредством рисоведения заключается в вымывании почвенных солей фильтрующимися преснымн оросительными водами и образовании пресной подушки грунтовых вол.

Abstract:The charge characteristics of the clay fraction of red soils under present investigation are summarized as follows:(1) The clay fraction of red soils carries a smaller amount of negative charge, but a greater amount of positive charge than that of neutral soils of temperate regions. The humus of the clay fraction of red soils has smaller calculated "apparent negative charge" than that of neutral soils, but it gives a relatively large quantity of negative charge to the entire clay. These characteristics are more significant for certain laterites.(2) The electric charge carried by the clay fraction of red soils varies distinctly at different pH and in different soil types. For a red soil derived from Quarternary red clay in central China, a variable negative charge appears at soil acidity strenger than pH 5, and a negative adsorption of chloride takes place at pH above 6. The laterite carries net negative charge at higher pH and net positive charge at lower pH with an isoelectric point of about pH 4. In the laterite isoelectric point increases after the removal of humus but decreases after the removal of humus and tree iron oxides.The vanability of electric charge of the red soils derived from granite in southern China lies in between that of the above-mentioned soils.

Abstract:Mechanical properties of soil including resistance to pressure, shearing, and deformation, internal pressure in relation to soil moisture content were studied with model experiment of paddy soils in rice stubble field and in wheat stubble field under laboratory condition. The mechanical strength of paddy soil in rice stubble field changed greatly with changing soil moisture content.This is due to a rapid development of atcraction of molecular resulting from intensive shrinkage. Paddy soils in wheat stubble field,however,were found to show less change in this respect. When soil moisture content was high, the internal friction of clay soil approached zero.Its shearing strength was effected by soil cohesion only and its internal friction increased with the change of texture from heavy to light. When soil moisture content dropped, the internal friction of all the soils studied increased rapidly and was effected by the strength of aggregates and the degree of roughness of the shearing surfaces. When soil moisture dropped to the lower part of plasticity, fragility of soil began to occur, but a certain degree of plasticity and viscosity still remained. Fragility may occur at high content of soil moisture to soils with light texture and weak arranxement. As the change of a soil from plastic to solid is a continuous process, a larger range of soil moisture content should be allowed for the demarcation between a plastic and a solid soil. Since the internal pressure of the paddy soil in rice stubble field increased rapidly upon decrease of soil moisture content, especially so in the case of clay paddy soil. Hence, for cultivation on such soils a higher optimum soil moisture content is suggested for the main purpose of tillage and to mmmize soil plasticity and viscosity. On account of this, it is necessary to have the plow to form soil blocks of smaller primary shear planes, to have a higher speed of plowine. to. have the land olowed twice. first far is advance of olantine and then immediately before planting, and to have a larger contact surface between soil and tire so as to increase the draft force of the tractor.

Abstract:1. Состояние порозности почвы,точно также как и форма,сплошность и способность передвижения почвенной влаги изменя в зависимости от механического состава и структурного состояния.

Abstract:The paddy soils derived from red earth are one of the essential paddy soil types in the middle sub-tropical regions of china. From the preliminary study on soil forming process of these soils in Kiangsi province, it was found that they possess not only the characteristics common to the soil forming process of ordinary paddy soils, but also their own specific properties. First, in the condition of double rice cropping system, the accumulation of soil organic matter, both in quantity and quality, represents certain zonality. Second, under the effect of dressing organic fertilizers and liming, it results in rebasification of the soil, and forms a paddy soil having a higher percentage of base saturation. Third, the redox process and leach-illuviated process are stronger, causing the ferric and manganic oxides in soil profile to redistribute obviously. Nevertheless, the paddy soils derived from red earth have also inherited some properties from the soil materials to a certain extent. The silica-alumina ratio and clay mineral types are similar to red soils.

Abstract:В начале настоящей работы указаны задачи изучения почвенного картографирования по азрометодам:1) разработка методики дешифрирования почв по азрофотоснимкам.

Abstract:Бассейн Б. и м. Хзйхз Внутренней Монголии находится в зоне сухой степн.

Abstract:The strongly acid salty paddy soils derived from noncalcareous allitic sediment are widely distributed in the estuary of Chu-Kiang of Kwangtung province. Before recent sediments have deposited, the whole areas were densely covered by mangrove populations. A buried layer of decomposed products from residual plants is often underlaid at varied depth of present soil profiles. This layer contains large quantities of sulphide compounds. Oxidation of sulphides under acid conditions during dry period results the formation of sulfuric acid, which reacts with the kaolinitic clay to form aluminium sulfates. Periodical floodings of sea water add salinity of the soil and upon hydrolysis of the aluminium sulphate give a strongly acid reaction. The toxicity of the soil is mitigated with the increasing thickness of overlaid sediments. However, large areas of strongly acid salty soil with underlaid organic matter layer less than 25 cm below the sulface appear very harmful to rice growth. Reclamation of the soil can be accomplished by: a) irrigation of river water, b) keep the soil in a permanent moistened condition, c) liming, and d) addition of surface soil.

Abstract:Микроорганизмы в агрегатах с разными диаметрами почвы "лоуту" в районе Гуаньчжун имеют закономерное распределение.

Abstract:A study was made on the physico-chemical properties of micro-aggregates in meadow drab soils, yellowish drab soils and red earths of different levels of fertility. The results show that with the use of organic fertilizers the soil fertility is raised gradually, the organic and mineral colloids become combined more tightly, the ratio of humic and fulvic acids appears to be greater; all these making the micro-aggregates of the soils with high fertility to possess the following properties: a greater external-surface area, a lower electrophoretic velocity, a lower phosphorus fixing power, a larger amount of easily releasable ammonium, a greater available water holding capacity, and a lower hydroscopic water and swelling coefficient. From the results mentioned above, it is evident that the otgano-mineral colloidal complexes are of great significance in soil fertility.

Abstract:From a glass-tube experiment on air-dried soil column the following results were observed: (1) The CaCl₂ solution moved upward from the "round water table" to a height of 108.5 cm in 136 days, (2) within the supported capillary water zone, the water front moved rapidly and the rate of water flow was great, but in the soil above that zone the movement of water front was slowed down and the rate of water flow decreased, (3) all kinds of soil water in liquid-phase (including film water) moved with salts, which caused the rate of soil water flow and soil evaporation to decrease.

Abstract:The paddy soils of Yükianghsien are generally deficient in phosphorus. Field experiments on application of phosphorus fertilizers nave the following results:1. Application of inorganic phosphorus fertilizers to Astragalus sinicus improved its growth and yield. The root system developed well;the number of nodules increased;the phosphorus content of the plant also increased significantly.2. In the field where Astragalus sinicus had been grown with dressing of phosphorus fertilizer,rice yielded higher than otherwise.3. Rice gave a higher yield with the same amount of phosphorus fertilizer applied to Astragalus sinicus prior to the rice crop than to the rice itself directly.It is therefore clear that to increase the yield of Astra,ealus stntcus by application of phosphotus fertilizers proves to be a very effective way of raising the yield of rice. And this has been carried out on large scale successfully in the people's communes.

Abstract:An extracting solution containing 0.5% α-α'-dipyridyl and 2 N barium chloride buffered at pH 7.0 with about 3% barium acetate was proposed for the determination of ferrous iron chelated by soil organic matter in paddy soils. It was found that the solution can extract the chelated, water-soluble and exchangeable ferrous iron,leaving the ferrous precipitates and ferric compounds unattacked. Two extractions with soil:solution ratio of 1:20 and stirring for 30 minutes are found satisfactorily. The amount of ferrous iron extracted correlated fairly well with the organic matter content of the soil.No chelated iron was found in the extractant from water-logged soils after having organic matter destroyed previously by hydrogen peroxide.

Abstract:Полевые методы обследования и изучения зрозии почв имеют большое значение для выяснения её закономерности и сезонной динамики.

Abstract:According to 507 determinations of volumeweight, specific gravity and total porosity of five main soil types in Heilungkiang province, it was found that there is a high correlation between volume weight and total porosity, and the later can be calculated directly from volume weight with an empirical equation.