Abstract:Un the basis of a series of soil survey made in the Hwaiho Valley(淮河流域),a plan on land classification for this area has been proposed as references for making arrangement in establishing irrigation systems, in land utilization, as well as in soil improvement. Three fundamental principles are considered to be important on land classification, i. e.(1)the practices in soil improvement must be considered in connection with those in land utilization, (2) the land classification should be considered on land utilization both of the present day and of the future time, and(3) the main factors and criteria adopted for land classification must be appropriate to the particular regional conditions. The main factors used in land classification of the Hwaiho Valley are suggested as follows:(1)soil types together with their physical and chemical properties, (2)geomorphological characteristics,(3)depth and chemical composition of ground water, (4) present status and further improvement in drainage and irrigation, (5) present status in land utilization and estimate on soil productivity, and (6) fundamental problems in the promotion of soil fertility.According to the factors just mentioned, a system of land classification has been proposed for the Hwaiho Valley where the land may be classified into seven main types.

Abstract:The roles of the natural development and some properties of the soils in this area are briefly discussed as follows: The soils are saline and calcareous in nature, in which over 70% of the total soluble salts are sodium chloride. Slight to moderate alkalinization may be developed, while the total soluble salt contents exceed 0.2%;but generally, there is no NaCO₃ present. The ground water table in this area is usally high, and the quantity and constituents of the salts in ground water are directly varied with and influenced by that contained in the above soils. The saline and alkali properties of soils in this area are originated from the parent materials, through the action of the sea water when they were deposited. As soon as the sea water ceased to affect, the soils as well as the ground water are gradurally desalinized by natural leaching and this process will be strengthened by the biological activities. As the desalinization of the soils is proceeded further, the ratio of Na⁺/Ca⁺⁺+Mg⁺⁺ in the soil solution decreased and the amount of the exchangeable Na on the soil colloidal complex is finally lowered. It is evident that desalinization also introduces the dealkalinization of the soils in this area; there is no hazard of strong alkalinization of the soils taken place through leaching.

Abstract:Для выяснения влиянии внесения различных удобрений на почвенные микрофлоры в кранозёмах в 1956 г.

Abstract:Pot culture experiments for the investigation of methods of application of powdered rock phosphate were conducted on a red earth and a slightly calcareous alluvial soil. The former is extremely deficiency in phosphatic nutrients, having a pH of 4.8, while the latter is a very fertile soil of about neutral reaction. Both soils received pretty supply of nitrogeneous and potassic fertilizers with following variations of phosphorus treatment. Rice was used as an indicating crop.

Abstract:Field experiment and Laboratory study were made for the comparision of transformation of nitrogen and the yield of rice in the paddy soil ploughed under dry and water-logged conditions. The drying of the soil after ploughing did not effect the ammonia-nitrogen content of the soil or the yield of rice under field conditions. After water-logging, the amount of nitrate-nitrogen decreased rapidly, and it disappeared within a few days as the soil intensely reduced. The effect of drying of different typies of paddy soil on the ammonia-nitrogen content were studied in the Laboratory. These results showed that there was a Large increase of ammonia-nitrogen content in the soil under water-logged conditions after drying as compared with the non-air dried samples. The magnitude of the increase in ammonia-nitrogen content was influenced by the characteristics of the paddy soil, such as the redox potential and the content of organic matter, especially the degree of drying. It is considered that the drying of paddy soils under cultivation is a powerful means in increasing the soil fertility and the yield of rice, especially for the subhydrogenic paddy soils, but in case of soils with high redox potential and low content of easily decomposable organic nitrogeneous compounds, such as those soils derived from loess-like material, on which this field experiment was conducted, the drying of the soil did not increase the amount of ammonia-nitrogen of the soil or the yield of rice.

Abstract:Определение кислотности почв для сотни образецов показывает,чтокислотность естественных краснозёмных и желтоземных почв обуслов-ленна исключительно присутствием в ней обменной алюминия.

Abstract:Chemical composition of plants, including 31 species of oxylophytes, 31 species of calciphytes, and 43 species of halophytes, growing on various parts of China, have been examined. Only leaves or pinnas of the plants were collected. Determinations were made to the ash, nitrogen, sulfur, phosphorus, aluminum, iron, potassium, sodium and calcium contents of the plants. In addition, the water soluble SO₄^2-, Cl^-, HCO₃^- of certain halophytes were also determined. It appears that the chemical composition of plants of the same ecological type is closely related to their taxonomic features. However, it shows significantly that the plants growing on the same soil type possessed more or less common chemical characteristics (Table 5).