Abstract:Ancient chronicles recorded that duriag the period of B.C. 1122-A.D. 220 saline-alkali soils occupied large areas along the sea coast of North China Plain. Inland saline-alkali soils were found in the northern part of the Plain, and also in the northern part of the Wei-ho Plain. In that period, amelioration of these soils were accomplished by using good irrigation-drainage system, by leaching, by rice planting and also by silting from periodical flooding water.

Abstract:Прн разработке мелиоративного районроваия по борьбе с засолением почв необходимо учитывать как особенность сочетания природных условий, так и особениость сельского хозяйства.

Abstract:Равнина Иньчуань расположена в зоне пустынных степей。Зональными лочвами её являются светлые сероземы, которые распространяются на высших террасах равнины.

Abstract:1. К проаинции сульфатно-хлорндпо-содового соленакопления относится Сунгари-ноннинская равнина, расположенная в зоне переходной от лесостепн к степн.

Abstract:В настоящей статьи изучена связь количества и состава клеящих веществ краснозёмных и краснозёмовидных рисовых почв с их структурообразованием в центральной частн провинции Цзянси путём коллоидно-химического метода и техники микроскопического исследования.

Abstract:Three groups of micro-aggregate, including water dispersed (G₀,sodium dispersed (G₁) and mechanical-sodium dispersed micro-aggregate (G₂),were separated by the peptization method from three groups of paddy soil derived from Quarternary red clay. The total amounts of micro-aggregates are 54, 58, 60% based on air-dry soil and the ratio of G₀+G₁:G₂ are 0.45, 0.94, 1.46 respectively.

Abstract:Южный район провинции Цзянсу является древнейшим районом земледелия.

Abstract:Орошение является важным мероприятием улучшения почвенного климата и повышения урожая с единицы площади.

Abstract:The forms of phosphate extracted from soils by various methods were established by calculation according to the law of solubility product. Ammonium carbonate solution may extract water soluble phosphates, CaHPO₄·2H₂O, CaHPO₄, Ca₄H(PO₄)₃·3H₂O,aluminum and iron phosphates, a little organic phosphorus and probably a little Ca₃(PO₄)₂, and Ca₅(PO₄)₃OH,similarly sodium carbonate solution may extract the same phosphates except those in organic forms. Sodium citrate solution extracts water soluble phosphates, CaHPO₄·2H₂O, CaHPO₄, aluminum and iron phosphates, and a little organic phosphorus. Lactate solution and Burriel-Hernando's extractant extract all forms of calcium phosphates in soils, but not aluminum and iron phosphates as well as organic phosphorus. Ammonium oxalate solution extracts all the above forms of phosphate from soils.Recovery test made on CaHPO₄, Ca₃(PO₄)₂ and FePO₄·4H₂O confirmed the results from calculation.The difference in the degree of correlation between the available phosphorus content as determined by the various methods and the response of crops to phosphorus fertilization was explained by the forms of phosphate extracted and the present knowledge of their availability.

Abstract:The present paper deals with the investigation on the argentometric and bromatometric methods for the determination of water soluble potassium with TPB (tetraphenylboron) in saline soils. Modifications of these methods are recommended.In the argentometric titration, the writer recommends the use of fluorescein as an adsorption indicator which gives a better color contrast of yellowish green fluorescence to pink. In addition, this method is comparatively simple and inexpensive.In the bromatometric method instead of the sintered glass filter an ordinary retentive, quantitative filter paper has been found adoptable in filtering the K-TPB precipitate. The bromatometric method, though comoarativelv tedious. gives a higher degree of accuracy and precision than the argentometric method.

Abstract:A modified oxidation-reduction titration method for the determination of nitrogen in organic matter after Kieldahl dieestion is described. The catalysts includine copper, selenium or mercury, which often interfere with the end point of oxidation-reduction titratIon, were removed by addition of zinc granules.