Abstract:Minerological composition and chemical characteristics of albic soil in seven typical profiles all over the Jianghuai drainage basin were analyzed.The result showed that the albic soils in this region are silty loam or silty clay loam with a silt percentage of 45%~76%.Having inherited the characteristics of the loess, the main constituent of the clay is Hydromica, accounting 60%~80%.Sa and Saf of the soil are 7.70~14.65 and 6.43~10.24 respectively.But Sa and Saf of clay are 3.53~4.42 and 2.40~3.35 respectively.Compared with the other layers, Sa and Saf of the soil at the surface layer are higher or the highest,which manifests the phenomenon of surface silicon enrichment.Significant variations of Sa and Saf, together with that of clay composition and particle aistribution, show a parent material of the whitish layer not the same as that of the B horizon, which is due to the supposed alteration of alluviation and sedimention of loessial deposit in Holocene follow ed by leaching and illuviation.

Abstract:Comparisons between the met hods of simulated crop production and synthetic land quality, for agroland economic gradation, and between their results are made, on the basis of the case study in Farm 148 of Xinjiang Autonomous Region.Results showed that: (1) the procedures of the two methods were almost the same, with results being fairly accurate and highly identical at a local-level; (2) the results of the method of simulated crop production were highly comparable, but its approach was very complicated; (3) the approach of the synthetic land quality method was simple and practicable, whereas the resuts between different areas were less comparable; and (4) with the combination of the two methods, it is easy to set up indexes of agroland economic gradation, comparable with each other and adoptable into the gradation network for the whole country, could be founded.

Abstract:The evaluation of land quality plays an important role in land use planning.In this paper, a quantitative and scientific evaluation of land quality based on GIS was made.Mathematical models, such as correlation analysis, hierarchical analysis, fuzzy evaluation, were applied in this study.The evaluation results accorded with the actual state of Suzhou, which indicated that this technique was feasible and scientific in land evaluation.

Abstract:In expounding the soil forming factors, this paper deals mainly with characteristics and vertical distribution of the soils of Mt.Hengshan, which is locat ed in Hunan Province.According to their diagonostic horizons and diagonostic charact eristics, taxonomic classification of the soils is proposed.The vertical distribution of soils has the upward order of Udic Fer risols, Xanthous Udic Ferrisols, Perudic Ferrisols and Perudic Luvisols; atmountain tops and steep slopes, Acid Perudic Cambisols is often distributed.

Abstract:Based on the technique of Geographic Information System and mathematical models, Dongguan Agricultural Modernization Experimental Field for Red Soil Areas was taken as the research site for soil quality evaluation.ArcInfo was adopted to data processing, and overlay analysis to spatial data analysis.Evaluation units were determined by combination of evaluation factors.AHP was applied to judge the weight of each evaluation factor.After evaluation criteria was fuzzified, variable weight evaluation was carried out.The results were calculated and mapped by using ArcView GIS software.Dif ference between results from evaluation with variable and constant weight was compared and analyzed.Results show that soil quality evaluation with variable weight is better than with constant weight.

Abstract:The establishment of an ecological index system for assessment of sustainability of cultivated lands has always been difficult due to lack of long-term cont inuous data of land properties.So usually the assessment results are qualitative instead of quantitative.In this essay an index system for assessment of sustainability of cultivated land is proposed and followed by a case study of Wujiang City, Suzhou City.The index system is divided into three levels, i.e.ecological, economic and social levels.To get a quantitative result in ecological assessment we set up a quasi-basic productivity model and a shadow price model and eliminate the contribution of technique improvement.Besides we assess the economic sustainability and the influence of agricultural policies.

Abstract:Soil fertility quality properties were studied by random gridding sampling and analyzing of soils at artificial Chinese fir forest sites with different tree ages in T onggu County and Dexi County, which are majortimber producers in the red soil region of Jiangxi Province.Properties, including litter layer, soil depth, organic matter, total N, CEC, BS, pH and available N, P, K, degraded sharply during the first 6-8 yeas after forestation.With increase in tree ages, these properties recovered slowly.But they were far below their initial levels even when the forests reached their mature stage.This paper concluded that soil fertility quality degradation is unavoidable under the current forestry management practices, and that improving forestation and reforestation methods, establishing proper soil management practices mainly aimed at protecting surface soil under seedling tree, and increasing input to forest soil, are key measures to keep soil quality from degradation.

Abstract:Incubation and pot experiments were conducted to study changes in organic-P fractions in calcareous soils after application of pig slurry and monopotassium phosphate (MPP) and their contributions to Puptake by rye grass.The results indicated that: (1) Liable, moderately liable and moderately stable organic-P of soils increased markedly after the application of pig slurry and MPP, with the middle one being mostly increased; (2) The liable and moderately liable organic-P made greater direct contribution to the total amount of P uptake by rye grass and all the three organic-P fractions had some indirect contribution; (3) Based on their comprehensive effects on the amount of P uptake by rye grass, the three organic-P fractions ranked in such order: liable organic-P > moderately liable organic-P > moderately stable organic-P.

Abstract:Methods of field experiment chemical analysis and data statistics were employed to study effect of potassium application on N, P, K content, nutrient uptake and dry matter accumulation of Yangmai 158 at different growing stages.Differences in nutrient uptake between seven cultivars including Yangmai 158 were also investigated at the same pot assium application level.The results indicated that, the peak of nutrient uptake and biomass accumulation appeared at the jointing and booting stages.Phosphorus content of the wheat cultivars was comparatively stable, but nitrogen and potassium contents fluctuated at different growing stages.It suggests that combined application of N, P at a suitable ratio is necessary for a good fertilization recommendation to meet the nutrient demands of wheat for high yield, high quality and high economic efficiency.

Abstract:Contents of water soluble organic carbon (WSOC) of 19 soil samples collected from the eastern part of China were determined and the spatial variation in WSOC were analyzed by means of trend surface and semevariagram analysis.It was found that WSOC contents in the studied samples ranged from 0.008 to 0.379mg g^-1 C with a median of 0.159mg g^-1 C.There is a decreasing tendency of WSOC content from NNE to NNW.Fulvic acid is one of the main sources of WSOC and pH plays an important role in WSOC accumulation in soil.

Abstract:Volatile contaminants exist in soils in three possible forms: dissolved in water, volatilized as vapor, and adsorbed by solid particles.The mass partitioning or sorption between them is an important factor that affects contaminant transport, which could be represented by retardation coefficient in the case of that equilibrium partitioning or sorption is attained.The most important mechanism affecting contaminant transport is nonequilibrium in sorption and desorption occurring in soil between solid particles and water phase, which should be described with a series of coefficients due to the innate particle-scale heterogeneity of soils.

Abstract:Ammonia volatilization was measured with the continuous air flow enclosure method in a paddy field at the Experimental Farm of Jurong Agricultural School in Zhenjiang hilly region, and its main influencing factor was investigated.The result showed that ammonia volatilization was obvious in paddy field after fertilisation with urea at the transplanting, tillering and booting stages of the rice crop.The result also showed that there was a visible ammonia volatilization which varied with the growth period and that the highest NH₃ loss rate occurred following the first top-dressing (19~26 days after rice transplanting), and the lowest NH₃ loss rate following the basal fertilisation (only 1%~3.8% of the N applied).The annual variation in ammonia volatilization was also observed due to the climate factors.An evident diurnal variation in flooding water pH and soil pH was observed after fertilization, and affected the am monia volatilization significantly.The rice straw application had a dissimilar effect which varied with the growth period.Total NH₃ loss over the whole rice-growing season increased with the N dose, but little difference was observed in the ratio of NH₃ loss to total N applied.

Abstract:Three typical paddy soils, hydragric paddy soil, bleached paddy soil and gleyed paddy soil, collected from the Taihu Lake region were used to investigate effect of acid rain on adsorption and desorption of copper by soils by using simulation and incubation approaches.Results indicated that when soils were leached with simulated acid rain, copper adsorption capacity of all three soils increased as compared to that of the un-leached control soils.Lower pH of leaching solution tended to bring about smaller increment in adsorption capacity.The amount of Cu released from the fraction of the KNO₃-extractable Cu was increased with the decrease in pH of the leaching solution, suggesting that soils suffering from acid rain leaching decreased their capability to buffer the heavy metals pollution.Soils with large adsorption capacity such as hydragric paddy soil and gleyed paddy soil were more heavily affected by simulated acid rain than the soils with small adsorption capacity (e.g.bleached paddy soil).

Abstract:Hy drochemical types and main chemical characteristics of the shallow groundwater in salt-affected soil area in Quzhou, Hebei were described and summarized in this paper.The data showed that the principal hydrochemical types of the groundwater were Cl-SO₄ and SO₄-Cl.The principalcation was Ca²⁺, and the next was Na⁺.The results also indicated that the mineralization and ionic strength of the groundwater in that area were high, especially for Cl-SO₄ and SO₄-Cl types.The mean mineralization of the groundwater was 3.11g L^-1 with the highest reaching 17g L^-1.

Abstract:Based on the data of a long term field experiment of dryland crops, this article points out that yield fluctuation, expressed in fluctuating coefficient, is a regular phenomenon in dryland farming.High-yield field has a similar fluctuation as compared with low-yield field but their mechanisms are different.Desiccation happened in the entire soil profile is a direct cause of the yield fluctuation for high-yield field, but low water absorbing capacity of the crop for low-yielding field.

Abstract:A method was found for calculating S input via atmospheric dry deposition.It consists of a series of calculation equations for surface layer turbulence charact eristic parameters (u_*、θ_*、L) based on profile meteorological data, for V_d of SO₂ and SO₄^2- particle dry deposition by making use of the resistance model, for S concentration of the atmospheric SO₂ and SO₄^2- particles, and thereupon for the targeted result.Experiments based on such a method were carried out in the Experiment Station of Red Soil Ecology, Yingtan, Jiangxi, Chinese Academy of Sciences and data collected at the experiment substation of farmland microclimate from Nov.1998 to April 1999.Results indicated that V_d of SO₂ and SO₄^2- part icle was 0.383~0.633cm/s (monthly mean 0.473cm/s), and 0.196~0.219cm/s (mont hly mean 0.205cm/s) respectively; total S input via atmospheric dry deposition per month was 4.35~16.32kg/m² (av.8.73kg/m².), of which 91%~98% (av.94.5%) was of SO₂ dry deposition.Total S input via atmospheric dry and wet deposition per month was 7.03~17.53kg/m² (av.10.51kg/m²), of which 61.9%~93.0% (av.80.2%) was of S input via atmospheric dry deposition.

Abstract:An indoor soil column simulat ion experiment was carried out to study salt dynamics in silt loam with different groundwater depths and salinities.The results obtained show that groundwater depth and salinity are both dominant factors affecting salt dynamics in soil profiles.Under condition of the same groundwater depth, when soils at the same depth reach dynamic equilibrium of salt, there is not able difference in soil solution salinity that is in positive correlation to groundwater salinity.Under condition of the same groundwater salinity, velocity of salt accumulation is in negative correlation to groundwater depth, but soil solution salinities at the same depth in different soil columns are similar after the soils there enter into dynamic equilibrium of salt.In order to value the effect of groundwater depth and salinity on salt dynamics, the models were built.

Abstract:在石灰性土壤无机磷中约有70%～80%是以Ca-P形态存在^[1～3]。水溶性磷肥施入土壤后短期内以磷酸二钙形式存在,随着时间的推移逐步向磷酸八钙转化^[4]。研究表明正常施磷情况下,一个生长季节在水溶性磷肥转化的各级无机磷中Ca-P约占80%^[5]。因此Ca-P在石灰性土壤中起着举足轻重的作用。蒋柏藩、顾益初按照Ca-P特点和有效性将其分成三级并提出了分级体系^[6,7],为研究石灰性土壤Ca-P提供了理论依据和手段。本文研究了占山东省土地面积三分之二以上的石灰性土壤中Ca-P分布、转化特征及长期施肥对Ca-P的影响,以期为这类土壤的磷肥施用提供理论依据。

Abstract:人工诱发非豆科经济作物结瘤固氮是国际生物工程领域的尖端课题,目前国内外尚未见成功的先例。中国·G实验室开展此项研究工作已有15年历史。大量实验表明,G式复合生物菌肥是一种新型、无公害的生物肥料,它能使作物增产、优质和改善生态环境,在一定条件下尚能使130多种植物形成根瘤。为了进一步弄清在人工条件下自然诱发根瘤的形成、结构、功能以及微生物与植物共生所产生的生理作用,我们以中国G实验室诱导的茄子、西红柿根瘤为材料,用光学显微镜、透射电镜和扫描电镜对根瘤的超微结构及其内生菌进行了观察研究,发现有两种自生固氮菌在根瘤内与植物共生,形成了新的共生体系。

Abstract:铵在土壤中的吸附特性,决定了维持该有效形态氮的能力。不少学者研究过铵的吸附问题^[1～4],研究重点一是探讨各种物理、化学处理条件下铵的吸附特征,如去除有机质、渍水处理、钙对铵的影响等^[2]。二是探讨不同土壤铵吸附的差别^[1,3]。这里,不同土壤多是取自全国不同地区,因而,铵吸附特征主要反映土性本身的差别。在这一方面,前人的研究未曾注意植被主导作用下产生的效应,即在相同土壤类型上,长期生长的植被对土壤铵吸附特征的影响。中国科学院鹤山丘陵综合试验站在华南丘陵坡地上栽植了多种类型的人工林,本研究以5种人工林土壤为材料,比较不同人工林对林下土壤铵吸附特征的影响。

Abstract:旱地农业与灌溉农业中作物经常面临的土壤干旱与湿润交替变化是实际田间环境^[1]。作物在生长发育的不同时期可能会遇上各不相同的土壤缺水胁迫,这些不同胁迫会对作物诱导出适应性的生理反应和伤害性影响^[2,3],对此进行研究和认识,可以在节水灌溉中控制作物生长发育不同阶段土壤水分来调节作物生理过程,避免伤害性变化的发生,而促进适应性变化的产生,以改善作物发育后期籽粒形成阶段根系和叶片的功能来提高作物产量、品质和水分利用效率,达到高效、优质的目的。本文主要研究玉米在土壤干湿交替过程中的耗水特性和叶水分状况的关系,探讨提高水分利用效率的机制,为节水农业提供优化供水模式。

Abstract:《中国太湖地区水稻土》是为参加在我国召开的国际水稻土学术讨论会(1980年10月)而撰写的。该书由上海科技出版社承印,熊毅先生主编。署名作者有徐琪、陆彦椿、刘元昌与朱洪官四人,在后记中注明李伟波、蔡蔚祺与刘多森参加某些工作,这七人乃是当时水稻土生态组组建时的全体成员。时隔二十有年,刘多森以“关于水稻土研究中某些数据与观念的讨论”(简称刘文)^[1]为题(土壤学报37卷1期),对该书进行评判。