Abstract:The application and study of Rhizobium inoculation technology in groundnut (Arachis hypogaea L.) production have been performed in People's Republic of China for over 30 years. This paper summarizes the studied results during 1956-1985 when the inoculated groundnut area had increased to 2.28 million ha in China. The yield increase of groundnut generally accounted for 354 kg/ha, being equivalent to an increment of 13.4%, and the profit/input is about 40:1.Of the 1,256 experimental sites, 90.9% obtained a yield increase of above 5%, and 81.8% had an net yield increase of 150-525 kg/ha, being very significant in the statistical evaluation. Some promising strains including 009, 97-1 and C₁ have been extensively screened, field evaluaced and put to commercial inoculant production and now have an applying area of more than 0.2 million ha/year. There are chiefly two inoculant production methods: (1) liquid culture in fermentor; (2) agar surface culture scrapted and agitated into suspension. Either (1) or (2) is impregnated with partially sterilized peat carrier which contains 1-2×10⁸ ells/g.Seed dressing of inoculant is generally adopted and inoculants pelleted with gypsum, lime or rock phosphates are also used. Granular application and top dressing of inoculants may increase the yield of groundnut. Inoculation seems best suitable for sandy loam soils. Plastic sheet covering may increase the effect of inoculation. Application of 300-450 kg/ha N-fertilizer can improve nitrogen fixation and nodulation. In soils deficient in phosphorus, the effect of inoculation can be enhanced by the supplemental application of phosphate fertilizer. Also, in some cases, ammonium molybdate will increase the effect of inoculation on groundnut yield.

Abstract:The present paper deals with the application of ⁵⁷Fe and Mossbauer spectroscopy in the study of magnetic genesis of red earth derived from basalt in Kunmin. The results obtained have shown that (1) maghemite, magnetite and titanohematite aer the main magnetic minerals in the soil, (2) these magnetic minerals mainly come from titanium dissociation titanium, and oxidization of original iron-titanium minerals such as titanomagnetite and ilmenite. In the soil-forming process, Ti⁴⁺ dissociation results in the minerals lends to be transformed into magnetite, maghemitc and hematite, formed the specific profile of magnetic suscepcibility and the strongest soil mastnetism in China.

Abstract:The red earths originated from Quaternary red clay are widely distributed in the hilly lands of central Jiangxi Province. Some physical and chemical properties of different particle size fractions of red earths were investigated. The main results are summarized as follows: 1. The clay minerals of the fine clay fraction(<0.001 mm) in the soils are predominated by kaolinites and vermiculites and contain some hydromicas and interlayer minerals. Distinct difference in the distributions of clay minerals was found between the coarse clay fraction (0.002-0.001 mm) and the fine clay fraction(<0.001 mm). 2. Chemical analysis of the samples showed that the content of SiO₂ decreased, but that of Al₂O₃ increased with the soil particles size fraction changing from coarse to fine, Which are consistent with the reported results by foreign pedologists. The sand fraction contained more Fe₂O₃ and had greater hygroscopicity and swelling capacity as compared with the silt fraction. These results are similar to those of bleached and permeable paddy soils in the Taihu basin, but different from forengn reports. 3. Plasticity and swelling were found only in the clay fraction(<0.002 mm). But in foreign reports these characters could be found in 0.005-0.001 mm particle fraction of some upland soils, and it might result also from <0.002 mm fraction. 4. The compressive strength of red earth was found only in<0.005 mm size fraction, but that of paddy soils of the Taihu basin mentioned above was found in <0.05 mm size fraction. It is considered that the plasticity and compressive strength have an obvious relationship with the content of fine clay in the paddy soils of Taihu, but these properties are weakened as a consequence of microaggregates with high stability formed by fine clay and sesquioxides in clayey red earth. Above-mentioned investigation is only a beginning for the study of the physical and chemical properties of different particle size fractions in upland soils of China. The experimental results may promote our understanding of the basic properties of soil particles, and supply a scientific basis for particles size fractionation and textural classification of soils in China.

Abstract:The effect of some common organic ligands on phosphate adsorption by hydrous Fe and Al ozides, Kaolinite and acid earth (red earth or ultiosl) was studied. In neutral solution with low concentrations of citrate, tratrate, oxalate and humate, the organic ligands appeared to be very effective in reducing phosphate adsorption on goethite, amorphous Al-oxide, kaolinite and acid soil, especially at low saturation of phosphate adsorption, Evaluation by K value from the fang. muir adsorption equation demonstrated that phosphate sorbed at the presence of organic ligands was much loosely bonded, and therefore was more available to plants as shown by the higher values of isotopic exchangeability and desorbability of the sorbed phosphate. Increasing concentrations of citrate from 10-5mol to 10-1mol decreased phosphate adsorplion on goethite, amorphous AI-oxide, kaolinite and acid soil by 37.9, 43.4, 47.7 and 80.4%, and increasing that of cartrate from 10-5 mol to 10-1mol decreased the their phosphate adsorption 27.6, 42.4, 42.7 and 50.6%, respectively. No significant amounts of Fe or/and A1 were dissolved in the equilibrium solution in the experiments.The maximum dissolution of amorphous Al- oxide in 10-1mol citrate solution was less than 0.2%. Since the newly exposed surface are very low in their affinity for phosphate and the dissolution amount of the soilds dissolved is so small that can not indicate the reduce of the total surface areas of the sorbents, the contribution of complex reaction of the organic ligands with Fe and A1 ions is very limited in the reduction of phosphate adsorption. It seems reasonable to conclude that the competition of organic ligands with phosphate for those sorption sites with high binding-energy is responsible for the reducing adsorption and increasing lability of the sorbed phosphate.

Abstract:Study on light and heavy minerals in red soils developed from basalt, and in red soils and mountain yellow soils developed from granite showed that (1) the contents of heavy minerals in red soils, derived from basalt were much higher than that in other red soils, especially Xuwen laterite in which the contents of heavy minerals were about 90% in 10-50 μ frac lion, 35-65% in 50-100 μ fraction, and 6-33% in 100-250 μ fraction, as compared to less 6% in most of soils such as red soil derived from granite. In fact, many heavy mineral grains in red soils derived from basalt consisted of quartz coated or cemented with ferric oxide which could not be removed by boiling 10% HCl. As is known to all, the specific gravity of quartz is 2.65, while that of quartz grains enveloped or cemented by ferric oxide raised to over 2.9, thus the quartz became "heavy mineral", and resulted in the increase of heavy mineral content in this soil.

Abstract:This paper deals with the effect of clay minneral (montmcrillonite) on the mineralization of nitrogen in proptein (gelation). The results obtained showed that (1) different states in which protein and clay mineral remained could lead to different mineralization percentages of nitrogen in protein in the order: complex < mixture < pure protein; (2) the more the protein-nitrogen in complex or mixture, the more the nitrogen mineralization, but the reverse was true for pure protein; (3) the mineralization percentage of nitrogen in protein was less in soil medium than in quartz sand meditun no matter what state it existed, showing that soil might proptect prorein nitrogen from degradation by microorganisms, and this protection varied with different soils wing to the different clay minerals in different ce soils.

Abstract:Sulphur deficiency in soils of China was estimated and indicated by a map (Fig. 1). Based on estimation of input and output of soil sulphur and crop response to sulphur fertilizers, it was stated that sulphur deficiency would not occur in large areas of China in the near future. Under certain special conditions, however, paddy soils submerged under cold water, some sandy soils might become sulphur deficient. The decreasing use of sulphur containing fertilizers, as a consequence of developing the chemical fertilizer industry, is predicted.

Abstract:Laboratory and greenhouse experiments were condu ted to study thte forms of selenium and the extraction of available selenium in several soils of Shannxi. Based upon the procedure of fractionation of phosphate proposed by Chang-Jackson, the forms of inorganic soil selenium were divided into three fraction—NH₄Cl-Se, Al-Se, and Fe-Se. The sum of these fractions accounted for 37-65% of total content of soil Se with an average of 48%. There was a significant correlation between the content of total Se and NaHCO₃ soluble}e and the three fractions, but no significant correlation between it and the water soluble-Se. The date obtained from the greenhouse experiment revealed that in the case of calcareous soil investigated, NaHCO₃ soluble-Se was very consistent with the plant Se uptake. There was, however, no significant correlation between H₂O soluble-Se and the plant Se uptake. This suggests that the extraction method of soil available Se with NaHCO₃ can be used to evaluate the availability of Se in calcareous soil. But the H₂O soluble-Se can not be used to estimate the possibility of Se to be taken up by plants.

Abstract:In this investigation, 3346 samples of surface soils, 305 samples of soil profile and 40 rocks were studied, 21967 analytical data of tots and available contents of Zn,Cu,Mn,Fe, B etc.showed that the average content of Zn,Cu,Mn,Fe in the rocks of Hubei were 60 ppm, 24 ppm,446 ppm and 1.8% respectively. The content of Zn,Cu,Mn,Fe in igneous rocks were higher than these in sedimentary rocks. The former were 61.7 ppm, 24.1 ppm, 382.8 ppm and 1.5% respectively, the later were 43.7 ppm, 20.9ppm,.335.9 ppm and 1.25% respectively. In igneous rocks: base rock > neutral rock > acidic rock, in sedimentary rocks: shale > sandy rock > limes-tone. The total contents of Zn,Cu,Fe and B in Hubei soil were comparatively high, the mean value were 83 ppm, 26.8 ppm, 596 ppm, 3.5% and 83 ppm respectively. The mean available contents were 0.65 ppm, 1.11 ppm, 29.7 ppm, 37.1 ppm and 0.33 ppm respectively. The contents of these elements in soil samples below critical value i.e. B 71% Zn 49%, Mn 17%, Cu 8%, Fe 7%. The distribution of micronutrients in different soil profile is quite different. In red earth Zn,Cu,Mn,Fe, B were cumulated in A horizon, but in yellow and yellow-brown earths, they were illuviated in B horizon. In paddy soil, Cu,Mn,Fe were leached and illuviated in B or C horizon, however Zn and B cumulated slightly in A horizon. The activity ratio of Zn and B in Hubei soils were all below 1%.

Abstract:The soils in intertidal zone in Jiangsu Province are formed and distributed under their unique conditions. They vary with vegetation and water conditions, which results in unequal multispectral characters Therefore, the types of soil can be recognized by computer image processing using LANDSAT CCT. This paper deals with the comparison for different methods for image processing including ratio processing, supervised and unsupervised classification, etc. used in recognition of soil types in intertidal zone of coastal region giangsu.The experiment showed that selected ratio was hater than sequenced ratio, supervised classification was better than unsupervised one. Among supervised classifications, the method of 13 training-land-classes was suitable, by which 3 sub-groups, i.e meadow coastal saline bog coastal saline soils and wet beach coastal saline soils; 4 genera according to different teztures and 7 species according to the degree of salinzation were recognized and classified under the soil great groups of coastal saline soils. Furthermore, the accuracy of the computer classification was checked with field actual measured data obtained from long-term experimental sites installed in the experiment region, which showed a mean relative error of 17.6%.

Abstract:The soils which distributed in the belt of transition between sea and land are the coastal saline soils developed under the differentactions of coastal landform, river hydrology, tidal wave, climate vegetation and activity of man. According to their differences in soil formation factors and genrtic characteristics,they can be divided into four subgroups: mud solonchak, sandy solonchak, meadow solonchak and mangrove solonchak. Their common characteristics are (1) that soil layers are thick but textures are different: (2) that genetic horizons are not obvious and have the swamping characteristics; (3) that soil salt content is more higher and of obvious salinization; (4) that main clay minerals are illite and kaolinite; (5) that soil nutrients are more higher and the ranges of pH-value are great. At present, the main problems in the use of the coastal soils are low utilization ratio of the soils, and unreasonable utilization of the soils resalting in distraction of mangrove resources. According the acture sctuation, some measues for reasonable use of the soils are recommcended.

Abstract:In desert alkalized soils, the alkalinity can be induced by both the hydrolysis of exchangeable sodium (or magnesium) in soil and that of the salts such as Na₂CO₃, NaHCO₃, MgCO₃, Na₂SiO₃, etc., at the same time, the determination of exchangeable properties is moredifficult due to the presence of line and gypsum in soils; therefore, hgdrolytic alkalinity is suggested by the authors as the new index for the division of alkalization of the sods. For providing our suggestion, hydrolytic alkalinity, pH, ESP, exchangeable sodium, residual sodium carbonate and SAR of 31 profiles were determined and the data obtained were studied using comprhensive numerical analysis method.

Abstract:The ordering characteristics of soil erosion class, in particular those in 5 and 7 band of LANDSAT MSS CCT image, were introduced, and the principle and operational procedure for soil erosion mapping by it were presented in this paper. The soil erosion map and the area of each class in the experimental region obtained by using the method were in good agreement with the results by conventional investigation, The main measures to ensure high accuracy and the low cost for the method are discussed, and it is considered that this method will have great prospect in practice and research on soil erosion mapping.

Abstract:近代对土壤水分能量的研究,不仅着眼于土壤本身,而且把土壤-植物-大气作为一个连续体系,统一考虑其能量关系,这是土壤水分能量研究的必然趋势^[1,2]。用热力学函数表述水分能量水平和状态,可以统一应用于土壤、植物和大气。

Abstract:科尔沁沙地位于我国东北西部的西辽河平原,系东北地区面积最大的沙丘分布区,区内沙化现象极其严重,其中地处内蒙古自治区赤峰市翁牛特旗东部的乌兰敖都地区为该沙地中的严重沙化、苏打盐渍化区。