Abstract:Study of the effect of deep alkaline ground water on the soil properties was carried out in 5 districts, 13 counties of eastern and southeastern Hebei Province from 1978 to 1979. Results obtained showed that the nse of deep alkaline ground water in irrigation resulted in incrustation of soil and the decrease of crop yields. It was found that such ground water contained much soda, and its chemical characteristics such as soluble sodium percentage (SSP),residual sodium carbonate (RSC) and sodium adsorption ratio (SAR) were all much higher than the critical levels accepted internationally, Laboratory experiments showed that after irrigation with deep alkaline ground water for 2, 3 and 4 years, soil exchangeable sodium percentage (ESP) increased from 3.2% to 8.7%, 17.2% and 28.7% respectively, with an annual average increase of 5.8%. While soil pH increased from 7.5 to 8.6, 8.9 and 9.3 respectively, with an annual average increase of 0.48. As a result, soil physical property was deteriorated,and soil permeability coefficient significantly decreased from 5.45 mm/hour after irrigation with alkaline ground water for two years to 0.15 mm/hour for 4 years.Alkaline ground water mixed with saline water in a proper proportion has a good effect on prevention from deterioration of chemical and physical properties of soil. It is considered that the application of alkaline ground water mined with saline ground water for irrigation may be a economic and practical method for improvement of water quality, and it is of great practical significance for the improvement of salin-alkali soil.

Abstract:The northwestern plain of Shandong is a main part of the plain of the Huang-Huai-Hai rivers and it is also an important area of grain and cotton production. However, because of the influence of drought, flooding, soil salinization and alkalization, crop yield in the area is still low and unstable. These calamities with closely internal interrelations should be considered integratedly in order to harness and control them in a reasonable way. The main measures for harness and control the calamities should be conducive to (a) the improvement of the water and salt regimes in the area on the basis of drainage, (b) reasonable exploitation and regulation of water resource on the basis of well irrigation, (c) reasonable land use integrated with maintenance and promotion of soil fertility and enhancement of rcsistance to the disasters, and (e) popularization of forestation and improvement of the ecological environment.

Abstract:The transformation of iron oxides in soil in the course of submergence and drainage, and its influence on the soil structure is discussed on the basis of incubation experiment. The yellow brown earth, the red earth and the laterite were added with various amounts of dried milk vetch powder, and incubated under the submerged condition with and without percolation. After 8 months, the incubated samples were dehydrated at various intensity and samples without dehydration were used for check (Table 2). The compleaed iron and amorphous iron oxides contents of incubated samples were influenced obviously by the addition of organic matter, submergence and dehydration, but the influence of dehydrated intensity on the compleaed iron content was insignificant (Table 3, 4&5).

Abstract:The present paper deals with the composition and oxidation stability of organomineral complex in aggregates of various sizes of red earth and alluvial soils with various fertility levels in Zhejiang Province. 1. For aggregates in diameter between 2-5 mm to 0.01 mm, the content of total organic matter increased with the increase in size of aggregates. The proportion of humus dissolved in 0.1 N NaOH and 0.1 M Na₄P₂O₇ mixture tended to decrease, and that of insoluble humin tended to increase with the increase in size of aggregates. The humic acid/fulvic acid increased with the increase in size of aggregates.2. For aggregates in diameter from 2-5 mm to 0.01 mm the proportion of G₁, fraclion (after Tyulin 1943) in total complex decreased, and the proportion of G₂ fraction increased with the increase in diameter of aggregates. The G₁/G₂ ratio decreased with the increase in diameter of aggregates. 3. The oxidation stability (Kos) of humus in larger aggregates tended to be lower than that in smaller aggregates in fertile soils. However, the oxidation stability (Kos) of humps in larger aggregates tended to be higher than that in smaller aggregates in infertile soils. It is suggested that the organo-mineral complex in larger aggregates of fertile soils consists of relatively fresh organic colloids, and that of infertile soils consists of the more stable organic colloids.

Abstract:The present paper deals with the characteristics of surface charge in zero point of charge (CPC) of certain soil colloids, and the problems of terms of the electrometric titration curves. Five soil colloids(<2u) separated from laterite, red earth, yellow brown earth, loess and black soil were used in the present study. The results obtained are summarized as follows: The magnitude of ZPC values of these samples was followed in the order of laterite (4.00),red earth (3.00), yellow brown earth (2.35),loess (2.25) and black soil (2.15). This sequence conformed to the soil zonality. The ZPC values were gradually reduced from south to north, and this tendency was related to the mineralogical composition and the content of organic matter of soils.

Abstract:Humic substances extracted from soils in loessial area where the annual precipitation and evaporation ranged from 340-800 mm and 720-2500 mm respectively were investigated by elemental analysis, x-ray diffraction, paper electrophoresis and infra-red spectrophotometry. Results obtained showed that the aromaticity and mobility of humic acid varied regularly with climatic conditions under which the soils formed. The drier the climatic conditions under which the soils formed, the higher aromaticity and lower mobility of humic acid. Among the humic acid of the soils studied, that extracted from ortho loessial soil had the highest aromaticity and the lowest mobility, while that extraded from yellow cinnamon loessial soil had the lowest aromaticity and the highest mobility.

Abstract:Three kinds of plant materials, mills vetch, azolla and rice straw were mixed with a soil,of negligible organic matter content and allowed to decompose in field under upland and waterlogged condition respectively. Samples of each plant material were talen at intervals over a period of one year and were partitioned into light and heavy fractions, observations made on the soil fractions obtained by this procedure included the determination of C, N content, sugar content and fractional humus composition. Results obtained are as follows: 1. Although the difference in % of C remained of plant materials with different chemical composition decomposing under the same environments or of the same plant materials decomposing under different environments was partly due to the difference in the amount of undecomposed or/and partially decomposed plant material, it was found that plant materials differed from each other in the amount of humus they formed after 1 year decomposition according to their chemical composition and the environmental conditions under which they decomposed. 2. The composition of the newly formed humus also varied with both the kind of plant material they derived from and the environmental conditions under which they decomposed. The sugar content of humus followed the order of rice straw>milk vetch>azolla which is also held for the original plant materials. The C/N ratio of the newly formed humus was much lower than that of the native soil humus, with that derived from rice straw the largest being 7.0, and that derived from milk vetch the smallest, being 6.5. The HA/FA of humus derived from rice straw was the highest, and that from azolla was the lowest, while the optical density (at 465 μm) of HA followed the reverse order. No regular difference in fractional humus composition between humus. formed under waterlogged condition and that under upland conditions was found.

Abstract:The existence of F. oxysporum f. sp. vasinfectum in relation to the fluctuation of propagules in soil under different edaphie conditions was studied in vitro. It was shown that the ehlamydospores of this fungus were easily formed in upland field. But under vaaterlogged soil condition, formation of chlamydospores was inhibited because of the lack of oxygen and the toxicity of CO₂. The germinated chlamydospores were capable of making further propagation under well aerated soil condition. However, in submerged soils, the germlings were easily suffered from bacteriolysis in soil in a few days. As a result, propagules decreased gradually. Part of the ungerminated chlamydospores persiated. in soil for a long time under submerged soil condition. Some of them can even survive more than 160 days. It is inferred that those chlamydospores still remained in soil might be one of the most important causative agents of reinfection, and it may be the reason that this fungus can not be eliminated and the wilt disease of cotton can not be completely controlled under rice-cotton rotation.

Abstract:The present paper deals with the application of magnetic susceptibility of soil for classification of paddy soils of Tai Hu basin. The results obtained has showed that (1) the magnetic susceptibility X value of paddy soils is much lower than that of their corresponding upland soils derived from same parent material;(2) the X value of the old paddy soils is lower than that of the young paddy soils derived from same parent materials;and (3) the higher.the magnetic susceptibility of the original upland soil, the more remarkable the decrease in the X value of the soil after putting under paddy cultivation. Evident differences of the magnetic susceptibility have been found in profiles of various paddy soils, because different soil moisture regimes and patterns of soil profile may affect the processes of oxidation and reduction of soils, crystallization and decrystallization, leaching and accumulation of ferromanganese minerals, as well as the movement of clay particles which are the principal carriers of secondary ferromagnetic minerals. Therefore, each type of paddy soils in Tai Hu basin has its own unique distribution of magnetic susceptibility in the profile. It may be used as a diagnostic criterion for identification and classification of paddy soils.

Abstract:棉花是黄土高原南部台塬区主要的作物之一。在田间条件下,它和小麦一样,对土壤深层储水,依然有明显的效应。1957年我们发现,尽管当年雨季提早于7月底结束,8、9两个月降水量只有28.8毫米,相当于同期棉花正常耗水量的13.5%,但在我所武功头道塬的轮作试验中,籽棉亩产仍达355斤,属正常水平。60年代前期,武功头道塬张家岗生产队早地棉花产盆,在遇到不同程度伏旱情况下,皮棉亩产稳定在百斤上下。为了鉴定土壤深层储水对棉花的供水作用和产量效应,进行了下述底墒效应试验。

Abstract:研究地下水(指潜水,下同)状况及其动态变化,对土壤发生与演变和改良利用有重要意义。本文根据东北典型的季节性冻土区实测资料,提出适合于本区的地下水研究方法、地下水分类和地下水动态模式图。