Abstract:China has a large area of gelisols distributed with a particular pattern, which is of great importance to the research on formaticn and distribution of gelisols in the world. The gelisols of China have two types: high-latitude and high-altitude gelisols. High-latitude gelisols are distributed in the Northeast region, 53-46°N latitude, with an area of 38.2×10⁴km² As their latitude is high but altitude is low, the scils have a series of characteristics influenced by the high latitude. High-altitude gelisols mainly occur in the Qinghai-Xizang plateau and western high anottutains, with an area of 176×10⁴km² which accounts for 75.7% of the total area of high-altitude gelisols in the Northern Hemisphere and ranks the first in the world. Most of them are dispersed in the regions south to 35°N latitude, and some even to 27°N latitude. Their location is high in altitude but low in latitude, and their characteristics are affected by the altitude.

Abstract:Activation and migration and their geochemical characteristics of elements under simulated submerged condition were studied, with red soils and fluvo-aquic soils as substrates. The results showed that leached elements came from different soil parts. The activities of Fe, Pvln, Ca and Mg were strengthened, and their migrating abilities increased. Mieration coefficient of Mn was nearly as large as that of Ca and Mg. The orders of elements migration in the two soils were different, in the red soil, being the order of Ca>Mn>Fe>Mg, Na>K>Si, P>Al, but Ca>Mg>Mn>Na>K, Fe>P>Si>Al in the fluvo-aquic soils.

Abstract:The distribution characteristics and dynamic changes of salt ions in the rhizos-phere of barley plants were investigated in rhizobag experiment, with salt tolerant variety Taiying No.5 (T) and salt sensitive variety CT16(S). It was found that pH value in nonrhizosphere of T barley was higher than that of S barley, while in rhizosphere, the contrary result was observed. Except for the K⁺ depletion, Na⁺, Ca²⁺, Mg²⁺, SO₄^2-, Cl^- and HCO₃^- ions were accumulated in the rhizosphere of T barley compared to those of non-rhizosphere. For S barley, K⁺ and Na⁺ ions were depleted whereas other ions were accumulated to certain degree. But for HCO₃^- ion, the degree of depletion or accumulation of other ions was lower for S barley as compared with T barley. The original content of soil salt ions and growth stage of barley plant would affect the distribution of ions at barley root-soil interface and relate to the salt ion absorption of barley plant.

Abstract:Studies on the reaction between phosphate and a calcareous soil in terms of sorption isotherms indicated that at low phosphat concentrations, phosphat was adso rbed on the surface of soil particles; the exchangeability of sorbed phosphate increased with amount of phosphate sorbed suggested that iron and aluminium oxides had an important role in phosphate adsorption in the soil. At high phosphate concentrations, precipitation occured due to formation of calcium phosphate, and the exchangeability of sorbed phosphate declined with the time of reaction and the amount of phosphate sorbed. Kinetic changes of soluble-P, ³²P exchangeable-P and Olsen-P in the soil with and without phosphate addition were also studied through a long period of incubation (up to 260 days) experiment, fractionation of phosphorus in the ³²P labeled soil was conducted finally.

Abstract:Relationships between common methods of measuring soil available phosphorus and the actual total amount of available phosphorus (TAP) in soils were studied. TAP was obtained by planting crops successively until the crop was very insufficient in P. Olsen-P (P_ol) was estimated ar only 170/0 of TAP, and anion exchange resin P (P_ar) at about 42% of TAP. EDTA+NaHCO₃-P(P_e) and ATR mixed CER-P(P_mr) were poorfy correlated with TAP. The correlation coefficient tretween Cowell total P and TAP was 0.825, significant at 0.001 level. The correlative coefficient between Cowtll inorganic P(P_ci) and TAP was 0.772, significant at 0.01 level. The content of organic P which is available for crop in Cowell total P was abowt 24-33%. The effects of soil critical P buffering capacity (CBC), organic matter, and clay contents in soil were of great importance. CBC was obtained from the isotherm of P adsorption at equilibrium P concentratian of 0.1μg/g, which is better than the MBC (maximum buffering capacity), when analyzing TAP. TAP can be estimated accurately by measuring some soil parameters (incfuding Cowell total P) and using three-factor regression equation of which the decides) coefficient (r²) was above 80%, much higher than that of single-factor (cowell total P) equation.

Abstract:Some problems eoncerning fractionatian of organic phosphorus in acid paddy soils using the Bowman-Cole methcd were studied and a modified sequential fractionation scheme was proposed. Four organic phosphorus fractions were identified as follows.

Abstract:The dynamics of decaying substances of plant residues during various decay periods was studied by using the DTA, TG and DTG analytic techniques. The results showed that the exothermic peaks at 330℃ in DTA curve was the specific peak of organic matter pyrolysis, and the dynamic energy characteristics of decaying substances of plant residues during decay process expressed by the enthalpy change (ΔH) of this exothermic peak were that the decay process of plant residues was a exothermic process as a whole, but it appeartd as an alternation process of endotherm and exotherm at some decay stage. Accorcding to the energy change charac-teristics the whole decaying process of plant rtsidues could be divided in to three stages, i.e., the fluotuating stage-the drastical decline stage-the stage tending to be stable. A significanx correlatiau was found between the enthalpy change (ΔH) and O.M.(%).Adding nitrogen could accelerate the decay process of plant residues and increase the energy flutuation extent at the fluctuating stage and shorten the drastical decline stage as well as result in advance of the stage tending to be stable. Whole decay process could be finished in eleven mouths under the experimental conditions. TG and DTG curves had the same characteristics as DTA.

Abstract:Samples used in the experiment were collected from red soils with various fertility levels in the organge plantations of Jianyang and Chantai, Fujian. After the light fraction being removed from the soil, oscillation and ultrasonic dispersion were used to isolate the various organo-mineral complexes from heavy fraction in water. The main characteristics of vanous complexes are demonstrated as follows.

Abstract:Water-soluble F^- in coastal saline soil of Jiangsu Province changed firstly from low to high content, then from high to low during desalinization process of the soil. Water-soluble F^- content was controlled by water-soluble Ca⁺⁺ content(F^-=a+bCa^++-1/2)..Because of the mutual exchange reaction of OH^- and F^--ion within soil colloid and solution, the water-soluble F^- content increased and decreased reciprocally with the water-soluble Ca⁺⁺ content but simultaneously with the pH value. The mainfactor controlling the content of soluble fluorine might be the activity product of CaF₂. CaF₂ is the main solid phase controlling water-soluble F^- in the saline soils along the sea coast of Jiangsu.

Abstract:A study on the characters of water retention, hydroconductibility, capillary rise and evaporation of calcic concretion black soil and their relationship with soil drought was carried out. The results obtained are summarized as follows.

Abstract:With improved Hungate anaerobic technique, the amounts of methane—producing bacteria (MPB) in the submerged paddy soil planting rice crop were determined by the MPN (The Most Probable Number) method and the rolll tube method at the same time. The esults obtained showed that the amounts of MPB during different growing periods of rice were significantly different, the amount of MPB grown on mixed substrate was the highest at the late tillering stage of early rice, up to 3.6×10¹⁰/g dry soil; that on H₂/CO₂ increased significantly at the vigorously tillering stage of late rice, reaching 3.1×10¹¹/g dry soil at milk ripening stage; the amounts of MPB grown on formate and acetate were higher, about 3.7×10⁸/g dry soil and 1.2×10⁸/g dry soil respectively at the vigorously tillering stage of late rice; and that of MPB grown on methanol-had no significant difference during the different growing periods being, about 3.5×10⁵/g dry soil. The amounts of MPB had no marked diffea-ence in soil at different depths.

Abstract:人参(Panax ginseng)主产于吉林省长白山区的林下暗棕壤及白浆土上。已有三百余年的栽培历史,人工栽培,多模拟野生条件,不施肥。近二、三十年来,随着种植面积扩大,注意改进栽培技术的同时,仿效农田施肥,基、种、追、喷肥并施,复合肥、专用肥皆用，缺乏针对性(人参、土壤)。为发展人参生产，合理施用肥料，从了解人参营养需要和土壤供肥水平人手，田间试验与室内分析相结合，进行了研究。

Abstract:土壤中磷素形态及其转化的研究,一直受到国内外学者的高度重视,张守敬和Jaokson⁷建议的无机磷分级体系尽管应用在酸性土壤上说明了许多理论和生产上的问题,但未能将石灰性土壤的钙磷从易溶的二钙盐到难溶的磷灰石加以区分,从而难于对其进行有效性评价,使石灰性土壤无机磷的形态形态分级研究受到限制。

Abstract:为了评价土壤供氮能力,除了广泛应用化学浸取法外,也在探索和使用物理化学方法。近几十年来,在古典的电渗析基础上发展起的电超滤法(Electro-ultrafiltration),即EUF法,是其中之受人注目者。用EUF析滤土壤氮素作为供氮指标,已有不少报道,但结果不一,解释各异。