Abstract:The field experiments were conducted on dryland of Changwu high-land in 1985 and 1986.Grain yield,water requirements and consumptions for wheat and corn, the changes in moisture storage down to a depth of 2-3m. were measured. Data of field experiments showed that there was insignificant difference at 5 percent level for grain yield among different treatments of water supply and there was extreme significance at 1 percent level among different rretments of fertilization under any level of water supply. It can be concluded that the balance between requirement and supply of water Etas been approxmately reached in the experimental region and the primary constraint for crop yield at present is poor fertility, not water deficit.Analysis of water balance on cropland showed shat satisfection ratio of water supply was 90.4-100% for wheat and 83.7-100% for corn in experimental years. Water supply of 200 mm to wheat was from soil water storage over whole growing period and more than 200 mm to corn in the period of summer drought or autumn drought.The change of soil moisture in soil profile down to a depth of 3 m. at harvesting period were studied. It seems that soil moisture higher than permanent wilting percentage is readily available.

Abstract:Spatial variability of silt and clay contents, macroaggregate and microaggregate contents and organic matter content measurements was studied by using stochastic theory and rime series analysis theory. The measurements were made on thirty sites (1×1 meters in size) selected at random in a silty-loamy paddy soil with an area of 127 m×71 m. Spatial variability of each soil property were characterized statistically by autoeorrelation function, semivariance function and Their diagram. The results show than the physical properties of paddy soil are nor completely disordered in field. There are spatial correlation for measurements at all the observation sites. The limit distance of spatial correlation of silt, clay, macroaggregate, microaggregare and organic maser content are 25, 25, 27, 23 and 37 meters, respectivily.

Abstract:In this paper, stochastic approach is applied to research soil moisrure quantitatively, and it is supposed that the soil water series can be represented by a general additive model and it proved that soil moisture series is supper posed by a periodic-deterministic process and a stochastic component. The periodic component is the effect of climates periodic fluctuation and crop evapoti anspiration, and the stochastic component is the effect of stochastic fluctuction of climate on soil moisture. Results of modeling the soil water process ar Wugnng. Shanxi, Yongji Shanxi, Fufeng. Shanxi has demonstrated that this method for modeling soil water content series is of higher precision.

Abstract:Study on the distribution of organic and inorganic cementing materials in different sizes of water stable aggregates in diameter of >5, 3-1, 1-0.5 and <0.25 mm separated from latosols, latosolic red earths and red earths by using a method of orderly sucessive removing the colloid from aggregates was carried out. Results show that with the increase in activity of clay particles and with the decrease in content of inorganic cementing material after exploitation of red soils the water stability of aggregates and the soil structural coefficient are decreased. These parameters, however, can be gradually increased in the application of organic material under the rational fertilization and management of soil. The relation of structural stability of red soils to soil tonality was also discussed. The strengthening structural stability of red earths in middle subtropics by application of organic material is more important than in tropical latosola.

Abstract:The crater retention, texture, microaggregate composition and other physical properties of main soils in north Anhui Province were measured. It has been tounde that the function θ=AS^-B could well simulate the soil water-retention curves under condition of medium and low suction, from this the specific water capacities of these soils were derived; and then the specific water capacities were obtained by analytical solution:C_θ=-(dθ/ds)=ABS^-(B+1).It is suggested that A·B value might be used to evaluate soil waterretention ability. Function type Ⅰ of S-shape curve (P=1/a₂+b₂c^-lgD) has been used to fit the particle distribution curve and type ⅡN(μ,σ)=a₂+b₂ lgD to lit the microaggregate distribution curve. The results obtained were satisfactory. Parameters of these functions and their relationship to soil water condition and otherr physical properties are also discussed.

Abstract:Qaidam is a plateau basin, with an elevation of 2600-3200 m, under climate arid. All the run off of about 440-500 million m³ yearly is converged into the river-sealed basin owing to reversed drainage, therefor, salt-water balance of the region mainly depends on evaporation. The deposition of salts in this basin have been started at least since Tertiary. In the salts deposited, besides large amounts of halite, carnatite and gypsum, those of B, Li, and Sr had also been enriched.

Abstract:Fourteen profiles from humid subtropical region were investigated using physical, ehemical, and mineralogical techniques. The results showed that zonality factors had impacts on soil properties to some extent within subtropical region, however, the factors like parent material were also important, its influences on properties such as CEC, iron free degree of clay were greater than that of bioclimate; Quaternary red earth was not the weathering products of the sandstone underlain but influenced by surrounding rocks or loess based on the particle size distributinn pattern and heavy mineral associations; while the decrease of weathering degree from bouom in surface in the profile was the result of climate changes from humid and warm to mild.

Abstract:In three low mountain areas. including those in Nanjing-Zhenjiang and Yixing-Liyaag districts of Jiangsu Province snd the northeast district of Jiangxi Province, 20 representative soil profiles with perfect data were collected for canonical variate analysis. The computing results show that on the coordinate plane of canonical variate 1 against canonical vartate 2, 90 percent confidence circles of 4 soil great groups classified in accordance with their tonal distribution in three low mountain areas respectively, i.e. basic yellow brown soils and othic yellow brown soils in Nanjinfi-Zhenjiang district, red yellow soils in Yixing-Liyang district and red earths in the northeast district of Jiangxi Province, are overlapped each other, and the points representing the individual profiles in character space illustrate that soil individuals evolve and transit each other gradually. In the three areas, all soil individuals embody the products.of different developing stages.

Abstract:A predicting equation for soil loss is derived by means of numerical analysis of the data from the experimental plots on eroded red earth developed on granite in Southen China. The equation is A₁=4·y_s·K·LS where A₁, is amount of soil losses y=5.459-0.472x₁+0.128x₂+1.715x₃-14.041x₄,x₁, to x₄, refer to rainfall, rainfall intensity, volume of runoff anti runoff coefficient respetively; K is erodibility and LS gradient-length of slope. This equation could be used for predicting the amount of soil losses in granite region of South China. Another predicting equation derived through soil erosion investigation and reservoir sediment measurement in the region of the Yangtze Gorges is A₂=0.8351·R·K·LS·C^-2.3,where A₂ is soil losses,R and C are rainfall factor and coverage of vegetation respectively, K and LS are the same as mentioned above. By using this equation, the soil losses of the region of Yangtze Gorges could be calculated.

Abstract:This paper deals with the mechanism of inftibition of NHe from urea hydrolysis in silt loam soil with low K content and the prevention of this toxicity by the application of farm manure and K on barley (Hordeum vulgare Jess). The results obtained are summarzed as follows: The pH of soil relating to the concentration of free NH₃ raised about 1.3 units 10 days ofter applying 122kg/ha urea in the soil, and a significant inhibition of NH₃ on barley growth was observed while the concentration of free NH₃ in soil solution was about 4 ppm. The membrave structure of both root and leaf tissue was severely injured by NH₃. The injured barley was low in respiratory rate and activities of photophosphorylation, nitrate reductase and Qlutamine synthetase, but high in the rate of photosynthetic electron transport and the contents of free amino acids.

Abstract:This paper deals with the distribution and available contents of B, Mn, Zn, Cu and Fe an soilis of Shandong Province. The range and mean value of the available contents of B, Mn, Zn, Cu and Fe in the soils are 0.04-6.79 ppm with an average of 0.48, 1.5-175.9 ppm with an average of 17.1 ppm, 0.04-14.56 ppm with an average of 0.54 ppm, 0.03-20.64 ppm with an average of 1.08 ppm and 1.6-162.0 ppm with an average of 12.6 ppm respectively. The range and mean value of easily reducible Mn is 9-1345 ppm with an average of 169 ppm. The content of available trace elements in different soil types varys greatly. It has been found that the Brown earth and Cinnamon soil in Shajia Shandong are severely deficient in B, the Fluvio-aquic soil and Shajiang black soil are deficient in Zn, the paddy soil is rich in Fe, Mn and Cu, and the Saline soil is rich in B. The availability of trace elements in soils influenced by many factors. The available trace element contents in the soils are offen increased with lowing of soil pH and increasing of organic materials. The contents of available trace elements soils of Sliandong have a regional distribution obviously. The soil in hilly region have a lower B content, moderated Zn content., and higher Mn content. The flood plain has a lower Zn content, moderate B content and moderate Mn content.

Abstract:NH₄⁺ adsorption isotherms of wormcasts obtained from earthworms fed with three different fodders in Nanning were stucied, and compared with the characteristics of those of the wormcasts from Wugong. The NH₄⁺ adsorption capacity of wormcasts was ordinarily larger than that of soils. The NH₄⁺ adsorption capacity of Nanning casts was larger than that of Wugong. The amount of NH₄⁺ adsorbed by wormcasts seemed to be related to the organic matter contained in wormcasts, espacially to the organic matter of middle temperature exothermic peak in DTA curve. The parateters of NH₄⁺ adsorption isothems of wormcasts from different fodders were different. In Langmuir equation, the constants K for NH₄⁺ adsorption isotherms of wormcasts derived from different fodders which were related to the bonding energy, were in the order of pure cattle manure > cattle manure+spoiled orange > cattle manure+residue of straw mushroom culture medium. While the parameters M，which were the adsorption maximum or total amount of solute capable of being adsorbed, were in the order of cat 1e manure-residue of straw mushroom culture medium > pure cattle manure > cattle manure+spoiled orange. The parameters b, which were indicated by the total effect of K and M, were in the order of pure cattle manure > cattle manure+spoiled orange > cattle manure+residue of straw mushroom culture medium.It is indicated that the cattle manure can not only be used as a good fodder for earthworms, but also be favorable for the high adsorption of NH₄⁺ by wormcasts, thereby forming a valuable adsorbent in soil.

Abstract:菜园土壤通常被认为是熟化度和肥力最高的土壤,但前人研究较少。研究不同地区菜园土壤在熟化过程影响下的基本性质、元素累积与转化特征,既有助于深入认识土壤肥力和熟化的本质,也有助于为菜园土壤的培肥管理提供科学依据。现将初步研究结果报道如下。

Abstract:土壤多糖对保持土壤团聚体的稳定性是极其重要的^[5,7],它有助于形成适宜植物生长的良好结构,因此对多糖的研究有其重要意义。高山草甸土多糖的研究国内外至今未见报道,本文将初步研究结果简报如下。

Abstract:稀有碱金属是指K、Na以外的Li、Rb、Cs三个元素。它们在自然界含量低,如地壳中含Li平均为30ppm,Rb为90ppm,Cs为6ppm,三者的比值为5:15:1。目前,在地质科学中,以稀有元素作为地球化学指示剂应用越来越广。关于土壤中稀有碱金属的研究报告至今不多。研究土壤中稀有碱金属的含量和分布特征对于探索风化和成土过程是有益的。本文根据近年来土壤环境背景值研究积累的一些资料作一初步探讨。