Abstract:Associated with the ecological survey of the Tumenjiang River Vally, on-the-spot investigations and observations about the functions of soil ecosystems were conducted and assessment criteria for the influences of topographic conditions on the function of soil ecosystems in the river valley were put forward, Results.obtained showed that (1) The ecological function was weakened with the increase of the altitude; The vertical differentiation of ecological function for the soils was in the orders: mountain dark brown earth>hilly dark brown earth>mountain brown coniferous, forest soil>mountain tundra soil and table land albic soil>high table land albic soil>low table albic soil; (2) The local climatic and biological conditions were influenced by topographical conditions; hydrothermal conditions were the main factors affecting ecological functions of the soils; deterioration of vegetative covEr and soil erosion promoted the degradation of soils; and (3) Number and kind of animal population could be used as the important criteria for assessment of soil ecosystems.

Abstract:Nine loessial soils sampled from North China plain, one, neutral soil and one, acid soil sampled from central and southern China respectively were used for phosphorus sorption and desorption study in this paper.A single Langmuir equation is the best one to describe the sorption data as judged by their very significant correlation coefficients (P<0.01).However,both Freundlich and Temkin equation are not fit very well to the sorption data in this study.Compared with the acid soil, the lbessial soils are the soil with relative low capablity of P sorption. The P sorption maxima of loessial soils as estimated by the single Langmuir equation range from 80 to 680μg P/g soil. While that of the acid soil is ahout 900 μg P/g soil Results have showed that the P sorption maxmna but not the P maximum buffering capacity (MBC=dq/dl) is a good pac-ameter to assess P sorption and supply status of loessial soils.Relationship between soil properties and P sorption maximu have been examed by simple linear regression analysis. Highly significant (P<0.01) positive corefations were found with the content of Fe₂O₃, clay, and CaCO₃ im loessial soil. CEC was also significantly (P<0.05) correlated with the P sorption maxima. When all the soils tested are considered, only the contents of Fe₂O₃ and clay are the major factors responsible for P sorption.P desorption data indicated that the loessiaL soils could be regarded as the soil with high capablity of P desorption. As campared with the neutral and acid soils tested, loessial soils arc more sensitive to P fertilizer.

Abstract:The adsorption affinity(logK_a) and desorption potential(logK_d, or relative desorption potential logK_dr) of cadmium in soil colloids were proposed and deduced of theoretically, as well as confirmed with experiment in detail. The definitions adsorption affinity and desorption potential were given by logK_d=log[Pa/(100-Pa)W/V]
logK_d=log[Pd/(100-Pd)V/W]
logK_d=logK_d+4.60
respectively, where Pa is adsorption % of Cd by colloids from solution, Pd is desorption % of Cd fram colloids with 0.1 M NaNO₃, W is weight of colloids and Y is volume of solution in the adsorption,or desorption processes respectively. Both logK_a and logK_d (or logK_dr) are intensive factors that deal only with the nature and characteristics of soil colloids, and are independent of the ratio of solid to liquid and concentration of Cd addition for adsorption or the ratio of liquid to solid and content of Cd for desorption in the certain range. logK_a depends significantly directly on pH, and logK_d(logK_dr) is markedly inversely correlated to pH.Some experiments applying log Ku and logK_d (or log lid,) showed that 1.logK_a could be used as a indicator of relative selectivity of soils or colloids for Cd; 2. logK_d, could be used as a indicator of relative fixed capacity of soils or colloids for Cd; 3. logK_a and logK_d could be used to prodict Cd adsorption % or pollution extent of soil colloids; 4. Cd uptake by wetland rice was significantly correlated to logK_a and logK_d (or logK_dr);Cd concentration in brown rice was decreased with increasing of logK_a or decreasing of logK_a (or logK_dr).Adsorption affinity(logK_a) and desorption potential(logK_d, or logK_dr) can reflect the resultant effect of the factors that affect adsorption or desorption of cadmium in soil colloids. It would be expected that logK_a and logK_d might be used in some research fields, such as the chemistry of soil environment, soil physical chemistry, the chemistry of plant nutrient, water chemistry, interface chemistry,etc.

Abstract:With dxt aim of determining the fluorine retention capacity of red earths and the fluoride migration in the soils after the soluble fluoride entered into soils, the experinents of isothermit adsorption and desorption and those of soil core leaching on red earths derived from limestone, basalt and sandstone were conducted. The results of study showed that the net adsorption capacity of F by soil was affected by parent material, texture and mineral composition of soils, the net adsorption capacity of F by the red earths derived from limestone, basalt and sandstone were 740,464 and 244 μg F^-/g. soil respectively. It is considered that net capacity of F may be used as an better indicator for fluorine retention capacity of soil than the adsorption capacity or the maxium adsorption capacity. The results also showed the contents of water-soluble F, exch-angeable F, citric acid extractable and 0.5 N HCl extractable F were very different in the sail with similar total F content and same parent material due to the difference in other soil properties, This indicates the desorption of F in soil is of most importance for F retention capacity of soil. From the data obtained, it can be found the retention capability of F by soil is very great, generelly, the cuxrent level of F in industrial effluents could not bring abom the pollution of ground water.

Abstract:Pairs of calcareous and non-calcareous soils under similar vegetation were collected from Taian, Nanjing and Kunming districts and the fractional composition of humus and structural characteristics of humic acids of these soils were studied. Results showed that. the HA/FA ratio of calcareous soil was consistently higher and the relative content of mobile HA was significantly lower than those of non-calcareous soils in the same location. Moreover, the humic acid extracted.from the calcareous soil was hjgher in aromaticity and content of carboxyl group and lower in contents of total nitrogen and amide nitrogen as compared with that extraded from the non-ealcareous soil. It seems that the chemical environment of calcareous soil is favorable not only for the decomposition of organic matter, but also for the polycon-densation of phenolic compounds with nitrogen-containing compounds, as well as the deamination of humic acids.

Abstract:This paper deals with the effect of application of organic materials on improving soil fertility. Experiments showed that PQ of various kinds of combined humus, in general, dropped in first year and rised back next year after organic materials were applied. The extent and time-keeping far the decrease of humification degree depended on the sorts and amounts of organic materials applied as well as the environment conditions under which the organic materials decomposed. The △logk and E₄/E₆ of various kinds of humid acids increased, while their RF values decreased by application of organic materials. Loosely combined HA varied in a wider range than stably combined HA. materials were not only higher but also The oprical density curves in treatments of organic steeper than those in the check.

Abstract:Nitrogen supplying capacity of three types of paddy soils in Tai-lake region were studied. Results obtained showed that (1) the mean value of the iricretnents of clay mineral-fixed arnynonium after anaerobic incubation of 9 air-dried soil samples was 17 ppm, which was equivalent to 28% of the increment of the exchangeable ammonium. It seems that the sum of the increments of exchangeable and clay mineral-fixed ammonium show-ld be taken as the nitrogen mineralization capacity-of the soils capable of fixing ammonimn; (2) results oatained in the field microplot experiments revealed that the contributions of subsoil to the nitrogen supplying capacity of the paddy fields ranged ffom 16% to 49%, with a mean value of 30%;and (3) difficulties in the prediction of nitrogen supplying capacity, of a paddy field with incubation technique are discussed.

Abstract:Studies on response of crops to potassium, and use of fertilizer-and soil-potassium in soils with different potassium supply potentials were made with successive cropping. The availability of potassium,varied with different potentials of potassium in soils, but both available and, slowly available potassium contents decreased in varying degree with the uptake of potassium by crops. The potassium in plant was partly the potassium released from minerals which constitutes only 0.04-1.58% of total mineral-potassium. The mineral potassium is released too slow to meet the requirement of a crop during the growing season. Comparison between the canon-exchange resin bag method and chemical or biotic methods in determining potassium release from minerals showed that the results obtained by resin bag method and biotic method were quite similar. The amount of potassium extracted by resin bag method was also very close to that taken up by rice or Sparrina artglica (r=0.916^**).It was also indicated that resin had method is more convenient than the biotic one.

Abstract:More than 3000 soil samples were collected in Liaoning Province and the available 13 (extracted by boiling water), Cu, Zn, Mn, Fe (extracted by DTPA) were determined by means of ICP, and the contents of above elements were repectively illustrated in 5 maps. It is shown that the contents of available Zn and B in soils of the province are widely lower, and in many regions they are at deficiency level, but those of Cu and Mn are mainly at medium or high level; as for Fe, it is lower in the northwest, but rather high in other regions of the province. In Liaoning Province, are distributed dark brown earth, brown earth, cinnamon soil, aerolian soil, meadow soil, paddy soil, saline soil, alkali soil and bog soil from mountain to plain and caost regions. The differences of the contents of available nucroeiements in these soil groups and subgroups were discussed, and the status demanding for microfertilizers in different sails and regions were demonstrated in the paper.

Abstract:The present paper deals mainly with the changes of thermoynamic parameters in the exchange of Zn-Ca of several typical soils. 50 ml solution containning Zn (10-200 ppm) was added to 2.50 g soils saturated by Ca, and then put in plastic container (vessel) and shaken occasionlly, standing under 20℃ and 50℃ for 72 hrs and then centrifuga,lized. The Zn and Ca in samples were determi.ne:d by Plasme Spectrometray. The results obtained showed that the selectisity coefficients (K_c) of the soils. was in the following order: Yellow browu earth>Red earth≥Latosol. K_c was decreasing with the increase of the saturation percentage for Zn on solid. It is considered from Fig. 1 that there are two adsoption sites with different energy on the solid surface, one has a stronger and another has a weaker affinity to Zn⁺⁺. In the process of Zn-Ca exchange, the effect of △H⁰ on △G⁰ was much more than that on the △S⁰, which was especially evident for Yellow brown-earth. It is.found from the changes of the theromodyuamical parameters that Yellow brown earths had a higher preference for Zn⁺⁺ and a tighter banding with Zn⁺⁺ than Red earths and Latosols,which is related with the differences in types and properteis of clay minerals.

Abstract:Kaolinite is dominant in clay mineral components of the relic paleo-soil on various rock in Zhoukoudian-area, which is accompanied by the hematite. Therefore, relic paleo-soil are considered as red earth type, that had been developed under the condition of wet-hot climate. Maybe the formation of relic. paleo-soil started in Pliocene. Clay mineral components in the middle portion of upper gravel layer and the 15-th layer in Pekipg Man,cave deposit at Longgushan, Zhoukoudian are composed of Kaolinites and illites. They also had been developed under wet-hot climate, but the wet-hot degree was slightly lowor than the wet-hot degree under which palesoil of red earth type was developed. Lower gravel layer of Longgushan and the devposits of the 14-th layer in-Peking Man Cave might be formed at the same geologic age. Based on the assumption that,clay mineral components are responsive to paleoclimate conditions, it may be concluded that during 300-500 thousand years when Peking Man lived in Zhonkoiidian, the paleoclimate had been gone through multiple fluctuations, but the general trend of the climateic conditions was changed from warm-temperate to temperate.

Abstract:近年来由于有机肥用量减少,化肥施用量增加,不少地区土壤有机质含量降低,物理性质变坏。改善土壤物理性质除增施有机肥外,施用土壤结构改良剂也是一种有效方法^[5-8]。作者就沥青乳剂和聚乙烯醇表施或混施对土壤物理性质的影响做了初步研究,结果如下。

Abstract:中国土壤学会第六次代表大会暨1987年学术年会于1987年11月6—12日在江西省南昌隆重召开。来自全国各省(市、自治区)土壤学会(台湾暂缺)的代表及列席代表共504人参加会议。提交大会的论文共481篇,大会印发了“论文摘要集”11,000册。会议以“保护土壤资源,提高土壤肥力”为主题开展了各项学术活动,总结土壤科学近几年来所取得的科研成果,交流了经验,讨论了当前和今后土壤科学的发展,共议土壤科学如何进一步为国民经济建设和农业现代化服务。会议除了进行大会报告之外,还按各学科分组进行报告和讨论。现将各学科的学术活动简报如下。