• Volume 40,Issue 2,2003 Table of Contents
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    • LAND REMEDIATION AND ECOLOGICAL RESTORATION OF MINED LAND

      2003, 40(2):161-169. DOI: 10.11766/trxb200210100201

      Abstract (3484) HTML (0) PDF 1.34 M (7055) Comment (0) Favorites

      Abstract:This paper reviews research and management of remediation and restoration of mined land in China aiming at promotion of theoretical innovation and technological development in this research field of China. The review is made mainly in view of soil science and ecology in mined land, including the following seven sections: (1) the development background during last 50 years;(2) the limitation factors for remediation and restoration;(3) physical and chemical remediation of degraded soil;(4) phytostabilisation and phytoextraction of metal polluted soil;(5) microbial animal enhanced remediation of polluted and degraded soil;(6) the technological requirements for utilization and management of remediated mined land;and (7) future research and development in field of mined land remediation and eco restorat ion in China.

    • CORRELATION OF SOIL TAXA OF HAINAN ISLAND BETWEEN CHINESE SOIL GENETIC CLASSIFICATION AND CHINESE SOIL TAXONOMY

      2003, 40(2):170-177. DOI: 10.11766/trxb200104020202

      Abstract (2024) HTML (0) PDF 1.90 M (3571) Comment (0) Favorites

      Abstract:Two hundred and thirty-seven soil profiles from Hainan Island were identified and classified according to Keys to Chinese Soil Taxonomy (3rd edition). The placement of 28 taxa, formerly sorted on subgroup level of Chinese Soil Genetic Classification System, in Chinese Soil Taxonomy was elucidated in the paper. The taxonomic soil classification of Hainan Island was proposed. And the correlation of taxa between Chinese Soil Genetic Classificafion (CSGC) and Chinese Soil Taxonomy (CST) was also discussed.

    • EFFECTS OF POLYACRYLAMIDE APPLICATION ON INFILTRATION AND SOIL EROSION UNDER SIMULATED RAINFALLS Ⅰ. INFILTRATION

      2003, 40(2):178-185. DOI: 10.11766/trxb200106190203

      Abstract (2209) HTML (0) PDF 1.20 M (2852) Comment (0) Favorites

      Abstract:Surface crust of soil, especially Loess, formed under the impact of raindrops will significantly affect rain water infiltration rate. Polyacrylamide(PAM) can effect ively prevent crust formation and improve soil structure and enhance soil permeability. To clearly relate PAM application with infiltration rate, experiments were conducted with rainfall simulator under laboratory conditions, at 3 different levels of rainfall intensity: 50 mm h-1, 100 mm h-1 and 150 mm h-1;4 slope gradients: 8.74%, 17.63%, 36.4% and 46.63% and 5 surface treatments: control, straw coverage and three PAM coverages-A, B, and C. Two rainstorms were simulated with a 24 h interval. Analyses were made to relate infiltration rates with PAM coverage and describe impacts of PAM application on infiltration.

    • SYSTEMATIC ASSESSMENT OF SOIL QUALITY AT FARM LEVEL IN TROPICAL AREA OF CHINA

      2003, 40(2):186-193. DOI: 10.11766/trxb200201300204

      Abstract (2404) HTML (0) PDF 944.42 K (2713) Comment (0) Favorites

      Abstract:Soil quality comprehensively represents the multiple-fold soil functions. Soil quality assessment is an important measure of sustainable soil management. This research was conducted on a tropical farm in Danzhou, Hainan, with rubber tree and other tropical fruits as main land use types. A systematic method for evaluating soil quality was adopted in which soil quality was evaluated according to the three major soil functions, i. e., nutrient availability, moisture availability and root suitability. The weight of every soil function and individual soil quality index was suggested based upon the earlier researches and the conditions of our research area. The soil quality indicators were normalized with one of the three commonly defined standard scoring functions (SSF). Based on GIS technology, soil quality of a tropical farm was evaluated and its spatial variation was presented. The result showed that the systematic assessment method based on soil function evaluat ion could comprehensively evaluate the soil quality. And with the support of GIS technology, the soil quality can be directly reflected by this method. The soils in the studied area have good water availability and root suitability while poor nutrition condition. But if properly managed, the overall soil quality condition can be improved within a short period.

    • SOIL ENVIRONMENT AND PRODUCTIVITY FORMATION PROCESS OF CORN IN FIVE TYPES OF FARMLAND OF HORQIN SANDY LAND

      2003, 40(2):194-199. DOI: 10.11766/trxb200106130205

      Abstract (2482) HTML (0) PDF 248.56 K (2865) Comment (0) Favorites

      Abstract:A field experiment was conducted on soil environment and product ivity formation process of corn in 5 major types of farmlands of Horqin. Results show that: (1) in terms of average soil water content during the growth period of corn the 5 main types of cropland were in the order of irrigated sandy loam (A, 12.4%) > irrigated loam sandy soil (E, 9.50%) > dry slop land of sandy loam (B, 8.87%) > dry land of sandy loam (C, 6.55%) > dry land of sandy soil (D, 5.70%);of average soil temperature they were in the order of D (22.04℃) > C (21.73℃) > B (21.40℃) > E (21.08℃) > A (21.05℃);and of integrated index of soil nutrients they were A (93.9) > C (84.3) > E (84.2) > B (65.3) > D (48.4);(2) in terms of plant height (cm) and biomass (kg m-2) of corn they were in a sequence of E (270, 2.96) > A (245, 2.70) > B (225, 2.12) > C (220, 1.86) > D (181, 1.32);(3) Correlation coefficients between biomass and soil indexes were in such an order as N, P, K (R= 0.860) > soil moisture (R= 0.837) > soil organic matter (R= 0.753).

    • AXIAL CHANGES IN ROOT XYLEM WATER POTENTIAL AND RADIAL HYDRAULIC CONDUCTIVITY OF CORN

      2003, 40(2):200-204. DOI: 10.11766/trxb200103050206

      Abstract (2023) HTML (0) PDF 563.77 K (2344) Comment (0) Favorites

      Abstract:Radial hydraulic conductivity of root is usually measured using potometer method and both root xylem water potential and the conductivity can be measured by solutions with different osmotic potentials. In this paper an improved method was presented to measure axial changes in root xylem water potential and radial hydraulic conduct ivity of corn at different distances from root apex. The results indicated that root xylem water potential decreased continuously along 9 cm from root apex. Soil drought not only decreased root xylem water potential but also increased the decreasing degree of root water potential along 7 cm from the root apex. The apical zone was the most sensitive zone to water stress. Root radial hydraulic conductivity gradually increased within the first 3 cm from root apex, reached maximum and maintained constant between 3 cm and 10 cm and decreased thereafter. Water stress decreased radial hydraulic conductivity earlier and made the gradient of its axial changes smaller.

    • THE ROLE OF EDTA IN Cd ABSORPTION AND TRANSLOCATION BY INDIAN MUSTARD

      2003, 40(2):205-209. DOI: 10.11766/trxb200103260207

      Abstract (2179) HTML (0) PDF 808.02 K (3653) Comment (0) Favorites

      Abstract:There are two theories for cation-EDTA uptake: One suggested that meta-l EDTA complex formed in the soil could increase metal solubility, and promote diffusion, and, hence, elevate potential uptake. An-other theory suggested the complexation of metals with EDTA reduced the activities of free ions in the soil solution, and, therefore, decreased uptake. Pot experiment was conducted to study the role of EDTA in cadmium absorption by Indian Mustard (Brassica juncea). H2O and NH4NO3 extractable Cd increased sharply in soils receiving EDTA treatment. Cadmium accumulation in the roots of B. juncea decreased significantly after EDTA application. However, Cd in shoots increased significantly when Cd added was over 130 mg kg-1 in soils, and Cd toxicity was observed. The results suggested that Cd concentration in-creased in soil solution after addition of EDTA, which resulted in increasing absorption and translocation when plant was suffering from toxicity.

    • IMPACT OF ARTIFICIAL FOREST ON SOIL MOISTURE OF THE DEEP SOIL LAYER ON LOESS PLATEAU

      2003, 40(2):210-217. DOI: 10.11766/trxb200103250208

      Abstract (2768) HTML (0) PDF 299.46 K (3564) Comment (0) Favorites

      Abstract:By the analysis of soil moisture profile of 10 m deep it shown that there is very abundant soil water resources (SWR) on Loess Plateau, SWR amount in the 3~10 m depths is 1 086.8 mm in the south and 524.1 mm in the north on Loess Plateau. SWR amount of various sites is about two times of rainfall amount in the same sites. There was a fluctuation and relatively steady of soil moisture change with soil layer deep. By comparing soil moisture of the control sites with artificial forest land it was found that mainly artificial tree types in Loess Plateau could take up soil moisture from 9~10 m deep soil layer and caused the dried soil layer of 3~8 m soil layer, of which soil water content is nearly to or lower wilting point during longterm. Dried Soil layer was a special phenomenon of eco-hydrology and also was an indicator the instability of artificial forest vegetation on Loess Plateau. It shown that artificial forest vegetation did not currently has function to conserve water supply on Loess Pleatu.

    • EFFECTS OF ACCOMPANYING IONS ON Cu2+ AND Pb2+ ADSORPTION ON SOIL COLLOIDS

      2003, 40(2):218-223. DOI: 10.11766/trxb200104100209

      Abstract (2023) HTML (0) PDF 254.66 K (3856) Comment (0) Favorites

      Abstract:Effects of accompanying ions on Cu2+ and Pb2+ adsorption on soil colloids in Shaanxi were investigated by surface complex model. Results indicated that pH(pH50), when Cu2+, Pb2+ adsorption percentage by tested soil colloids approached to 50%, showed a trend of Cl- > SO42- > oxalic acid> citric acid > NO3- in every ion system;that in terms of Cu2+, Pb2++ complex constants (logKMint) the order was just the other way round;and that specific adsorption characteristic values (n), reflect ing proportions of specific adsorption and electrostatic adsorption, showed a trend of NO3- > Cl- > SO42- > oxalic acid> citric acid.

    • EFFECTS OF LOW MOLECULAR ORGANIC ACIDS ON ADSORPTION OF ACID PHOSPHATASE AND BSA BY SOIL COLLOID AND CLAY MINERALS Ⅰ. EFFECTS OF ACETIC ACID

      2003, 40(2):224-231. DOI: 10.11766/trxb200104080210

      Abstract (2251) HTML (0) PDF 332.30 K (3168) Comment (0) Favorites

      Abstract:Effects of pH and acetate concentration on the adsorption of acid phosphatase and BSA by soil colloid and clay minerals (SCCM) were studied. The results showed that the pH for the maximum adsorption of enzyme and BSA were between the IEP of protein and the PZC of SCCM. In the acetate systems, the amount of enzyme and BSA adsorbed by SCCM increased in the order goethite >> yellow brown soil> latosol > kaolinite> δ -MnO2. Remarkable influences of acetate concentrat ion on the amount of adsorption and the binding energy of enzyme and BSA were observed. With the increase in acetic acid concentration from 0 to 200 mmol L-1 in the system, acetic acid exhibited an initial enhancing effect followed by an inhibitingaction on the adsorption of enzyme and BSA on SCCM. The changes in binding energy (K value) for enzyme and BSA by SCCM were contrary to the trend for maximum adsorption. The possible mechanisms for the influence of acetate on the adsorption of enzyme and BSA by SCCM were discussed.

    • SIGNIFICANCE OF SOIL ORGANIC MATTER, TOTAL N AND MINERALI ZABLE NITROGEN IN REFLECTING SOIL N SUPPLYING CAPACITY

      2003, 40(2):232-238. DOI: 10.11766/trxb200105210211

      Abstract (2541) HTML (0) PDF 825.17 K (3852) Comment (0) Favorites

      Abstract:Twenty five surface soil samples taken from different sites and 36 soil samples from 6 soils, each consisting of 6 layers, were used to study the relations of the mineralizable N to the organic matter and total N. The mineralizable N was estimated by an aerobic incubation. The results showed that the mineralized N was very well correlated with the organic matter and total N for all the soils. However, the ratios of mineralized N to the organic matter or to the total N were remarkably different, and the mineralized N was more correlated with the ratios. These results strongly demonstrated that the amounts of the mineralized N were dependant on both the contents and the potentially mineralizable proport ions of the total N and organic matter, and that the contents of the total N or organic matter were unable to provide the information on the proportion made available to plants. Field experiments were conducted using 15 soils containing low accumulated nitrate N in soil profile, and the results revealed that the mineralizable N had good correlation with either wheat yield or N uptake. However, the organic matter or total N was not so as the mineralizable N, though the total N had a high correlation coefficient with wheat yield in case without P addition. The result further confirmed that determination of mineralizable N had its significance, and could not be replaced by determination of organic matter or total N.

    • EFFECTS OF UREA AND KNO3 ON PROCESSES AND PRODUCTS OF INORGANIC NITROGEN TRANSFORMATION IN PADDY SOILS I.PROCESSES OF INORGANIC NITROGEN

      2003, 40(2):239-245. DOI: 10.11766/trxb200204250212

      Abstract (1995) HTML (0) PDF 1.47 M (3073) Comment (0) Favorites

      Abstract:By using 15N techniques, effects of urea and KNO3 on processes and products of inorganic nitrogen transformation in Hydragric paddy soil and Gleyic paddy soil, collected from Wuxi and Yingtan, respectively, were investigated under flooding conditions at 25. The results showed that coupled nitrification and denitrification of NH4+ occurred in both paddy soils. Oxidation of NH4+ in the Gleyic paddy soil amended with 15N-labeled urea alone was terminated at the product of NO2-, but denitrification product N2 was observed, implying a high possibility of aerobic denitrification. The decrease in NO3- concen-tration in both soils, followed the firstorder reaction. The reaction constant of the Hydragric paddy soil was about 10-fold that of the Gleyic paddy soil. Addition of urea raised soil pH and stimulated DNRA process in the Hydragric paddy soil, and both denitrification and DNRA processes in the Gleyric paddy soils. However, denitrification was a dominant process in NO3- transformation. The differences in the effects of urea and KNO3 on the processes and products of inorganic nitrogen transformation in paddy soils would primarily result from their different effects on soil pH and secondarily from concentration effect.

    • LAW OF NUTRIENT EQUILIBRIUM, GAIN AND LOSS IN BLACK SOIL FARMLAND

      2003, 40(2):246-251. DOI: 10.11766/trxb200107020213

      Abstract (2196) HTML (0) PDF 1.49 M (3085) Comment (0) Favorites

      Abstract:Results of an 11 year fixed experiment indicated that the spontaneous nutrient supplying capacity of the typical black soil farmland tested varied in the following way, its N supplying capacity declined from 92% to 50%~60% in the plot without nitrogenous fertilizer, its phosphorus supplying capacity decreased from 98% to 80%~90% in the plot of no phosphorous fertilizer, and its potassium supplying capacity dropped slowly from 100% to about 90% in the plot of no potassium fert ilizer. Nutrient equilibrium of the soil and its changes controlled nutrient gain or loss in the farmland The correlation coefficient of the model between gain and loss of available phosphorus and of total phosphorus is Y= 2.895+0.134X, the correlation coefficient of the model between gain and loss of readily available potassium and of total potassium is Y= 18.81+0.163X.

    • EFFECT OF DIFFERENT NITROGEN FERTILIZERS ON TRANSFORMATION OF SYNTHESIZED PHOSPHATES IN CALCAREOUS CHAO SOILS

      2003, 40(2):252-260. DOI: 10.11766/trxb200103140214

      Abstract (1879) HTML (0) PDF 357.08 K (2087) Comment (0) Favorites

      Abstract:Pot trials were conducted to study the effects of NH4+-N, CO(NH2)2 and NO3--N on the transformation of several synthesized phosphates in light clay calcareous Chao soil. The results indicated that treatment with maize and no added P decreased to different degree the content of all inorganic P species in rhizosphere. DCP, OCP, Al-P applied mostly transformed into other inorganic phosphates other than dicalcium phosphate, octacalcium phosphate, aluminum phosphate respectively. However, Fe-P, especially FA applied, mainly existed in their corresponding forms in soil and the condition in rhizosphere is favorable for their transformation into other inorganic phosphates. The transformation of Al-P and FA applied in soil were significantly affected by forms of nitrogen fertilizer. Al-P coupled with NO3--N predominantly transformed into apatite. FA coupled with NH4+-N was more favorable for its transformation into other inorganic phosphates except apatite than coupled with other two N forms. The content of ferric phosphate in rhizosphere and bulk soil significantly increased in all treatments and accumulated in rhizosphere when coupled with NH4+-N and CO (NH2)2. Besides dicalcium phosphate and aluminum phosphate content also increased markedly and both of them were lower in rhizosphere than those in bulk soil. Their transformations in soil, especially in rhizosphere, were consistent with their availability.

    • EFFECT OF N FERTILIZATION ON YIELD,NITRATE CONTENT AND N APPARENT LOSSES OF CHINESE CABBAGE

      2003, 40(2):261-266. DOI: 10.11766/trxb200101150215

      Abstract (2320) HTML (0) PDF 697.29 K (3064) Comment (0) Favorites

      Abstract:Field experiment with 6 level N rates was conducted in 1998 to study the effects of N rates on yield, nitrate content of Chinese cabbage and N apparent losses. The results showed that, the optimum economic N rate was 310 kg hm-2 (N), the nitrate content of plant and the N apparent losses in soil plant system increased with increasing N rate. It was not possible to coordinate the yield effect, crop quality effect and environmental effect under experimental condition. Reducing vegetable nitrate content by other strategies, improving current planting system and studying environmental economics of fertilization, are the main problems to be solved in the future.

    • STUDIES ON THE RELATIONSHIP BETWEEN SOIL PROPERTY CHANGES AND SOIL DEGRADATION UNDER 1ST AND 2ND ROTATION MASSON PINE PLANTATION AT DAQINGSHAN

      2003, 40(2):267-273. DOI: 10.11766/trxb200105040216

      Abstract (2342) HTML (0) PDF 1.07 M (3630) Comment (0) Favorites

      Abstract:This article emphatically reviews the changes of soil physical properties, chemical properties, biochemical activities and soil microbe species and their relationship with the growth of masson pine of 1st and 2nd rotation plantation at the similar conditions. It shows that masson pine can ameliorate soil physical properties, especially to the layer 0~20 cm. Successive rotation of masson pine improve the contents of organic nutrient a little in half-matured stand while the contents of avail. N, rapidly avail. P, Ex-Ca2+ and Ex-Mg2+ apparently decrease. The activities of soil polyphenol oxidase, protease and urease decrease, but soil catalase, invertase and acid phosphorylase in the layer 0~40 cm increase. It also finds that the quantity of bacteria, actinomyces and fungi in soil under masson pine plantation of second rotation is more less than that of first rotation, especially the quant ity of azotobacter. The research results will support scientific data and scientific basic for reasonable management of masson pine plantation.

    • EFFECTS OF LONG-TERM POTASSIUM APPLICATION ON YIELD AND SOIL POTASSIUM IN RICE-WHEAT CROPPING SYSTEM IN PURPLE SOIL

      2003, 40(2):274-279. DOI: 10.11766/trxb200103270217

      Abstract (2137) HTML (0) PDF 1.89 M (2794) Comment (0) Favorites

      Abstract:Effects of long-term K application on crop yield and soil K content and forms in rice-wheat rotation were studied. The results showed that long-term K application markedly increased crop yield, the balance of the available K in purple soil was maintained and the ability of soil to supply K was raised. A joint application of rice straw ( 7 500 kg hm-2a-1) and chemical K fertilizer ( about K2O 140 kg hm-2a-1) is recommended to keep the balance of K in purple soil.

    • SOIL NUTRIENTS, MICROORGANISMS AND ENZYME ACTIVITIES OF DIFFERENT STANDS

      2003, 40(2):280-285. DOI: 10.11766/trxb200103200218

      Abstract (2801) HTML (0) PDF 233.56 K (5374) Comment (0) Favorites

      Abstract:The nutrient concentrations, microorganisms and enzyme activities of soil in pure Eucalypyus urophylla, Acacia mangium, Tectona grandis, Taxodium distichum stands and in mixed stands of Castanopsisfissa and Pinus elliottii, Schima wallichii and Pinus elliottii, Castanopsis fissa and Pinus caribaea were studied. The results show that compared with P. massoniana stand, A. mangium, T. grandis, T. distichum stands and mixed stands with conifer and broadleaf tree could increase organic matter content and improve the nutrient status of soil, whereas the effect of E. urophylla changed with nutrient type. The microorganism amount of P. massoniana stand soil was bigger than those of mixed stand soil of C. fissa and P. elliottii and pure stand soil of E. urophylla, but it was smaller than those of other stand soils. Except for E. urophylla stand soil and A. mangium stand soil, the enzyme activities of other stand soils were bigger than those of P. massoniana stand soil. In a word, E. urophylla was not good at improving soil fertility, whereas other stands could improve soil fertility.

    • EFFECT OF TRIAZINE ON SOIL ENZYME ACTIVITY

      2003, 40(2):286-292. DOI: 10.11766/trxb200107100219

      Abstract (1756) HTML (0) PDF 270.43 K (2249) Comment (0) Favorites

      Abstract:Influence of trazine prometone and bladex on soil catalase and polyphenol oxidase activities was investigated at concentration of 0, 1, 10, 100 L g g-1 and prometon+ bladex 50+ 50 L g g-1 respectively. Results showed that both prometone and bladex can stimulate the activities of soil catalase and polyphenol oxidase, and bladex has stronger effect than prometone. The mixing application of two triazines hasn't displayed obviously synergistic effect.

    • MUTATION BREEDING OF METHYL PARATHION DEGRADING STRAIN DLL-1(PSEUDOMONAS sp.)

      2003, 40(2):293-300. DOI: 10.11766/trxb200102150220

      Abstract (2141) HTML (0) PDF 310.68 K (2732) Comment (0) Favorites

      Abstract:Four mutants (DLL-E1, DLL-E2, DLL-E3 and DLL-E4) were obtained by UV and LiCl mutation breeding of Methyl Parathion degrading strain Pseudomonas sp. DLL-1. Studies on their abilities to degrade Methyl Parathion and p-nitrophenol, substrates, activities of ectoenzyme and crude enzyme showed that all mutants have higher biological activities compared to the original strain. Further studies on resistance and degradation of Methyl Parathion and p-nitrophenol by DLL-E4 was conducted.

    • THE OSMOREGULATION MECHANISM OF SALT TOLERANT STRAIN A1 (ARTHROBACTER sp.A1)

      2003, 40(2):301-305. DOI: 10.11766/trxb200107290221

      Abstract (1852) HTML (0) PDF 216.91 K (2214) Comment (0) Favorites

      Abstract:A bacterial strain A1 was isolated from activated sludge that treat with hapersaline waste water and identified as Arthr obacter sp. this strain was capable of growing on MM with the NaCl contents 0.1 mol L-1~2.0 mol L-1 and phenyl acetic acid as the sole source of carbon and energy. The osmoregulation mechanism of this strain was studied, it was found that the intracellular accumulation of K+;free amino acid;QAC increased with the increasing of salinity. The intracellular amino acid and QAC contents increased immediately when salt was added suddenly to culture to a final content of 1.0 mol L-1. The contents of amino acid and QAC increased by 2.1 times and 4.9 times respectively in 40 minutes.

    • >Research Notes
    • SEDIMENT ENRICHMENT MECHANISMS OF NITROGEN AND PHOS-PHORUS UNDER SIMULATED RAINFALL CONDITIONS

      2003, 40(2):306-310. DOI: 10.11766/trxb200111130222

      Abstract (1978) HTML (0) PDF 204.40 K (2971) Comment (0) Favorites

      Abstract:在农田暴雨径流条件下,地表径流携带的侵蚀泥沙比原土壤有较高的养分含量,表现出对氮磷等养分的富集作用,富集系数(Enrichment Ratio,ER)随侵蚀泥沙流失的增加而减少[1].大多文献把侵蚀泥沙对养分的富集归因于径流对土壤表面富含养分的有机质和粘粒的选择性搬运[2].由于被选择搬运的农田表层土壤有机质在侵蚀泥沙中只占很小的一部分,因而对侵蚀泥沙的养分富集贡献也一定很小;同时,土壤和侵蚀泥沙氮磷养分主要是存在于不同粒径的土壤团聚体中,即颗粒态氮磷的流失主要是通过结合有机氮磷的泥沙迁移作用完成的,侵蚀泥沙的养分富集作用也不是简单的粘粒的选择性搬运.

    • DEDUCTION OF CHARACTERISTIC CURVES OF SOIL MOISTURE DETENTION

      2003, 40(2):311-315. DOI: 10.11766/trxb200106090223

      Abstract (2484) HTML (0) PDF 989.66 K (4207) Comment (0) Favorites

      Abstract:在研究土壤水分入渗、蒸发、土壤侵蚀及溶质运移过程中,土壤水分特征曲线是推求各种水分运动参数的重要手段[1,2].目前测定土壤水分特征曲线主要是用压力膜法;这种方法费时多,花费大,极不方便,严重制约了研究工作特别是数学模拟工作的进展.在野外研究土壤水分运动时,人们一般是进行分层(如0~10cm、10~20cm)采样测定;有的测定是原装土样,有的测定的是搅动土样,其测定结果作为每层的平均值.而实际上这种平均值是相当不准确的;首先由于在土壤剖面中,由于土壤颗粒组成变化、耕作层与下层土壤的有机质含量的差别对土壤水分特征曲线的影响是相当明显的;更重要的是从土壤壤水分特征曲线本身的特点来看,它与土壤质地、有机质含量等不存在线性相关,因此土壤水分特征曲线是没法用平均法表示的.

    • STUDIES ON SOIL FERTILITY CHANGES OF YOUNG FIR FORESTRY

      2003, 40(2):316-319. DOI: 10.11766/trxb200110150224

      Abstract (1685) HTML (0) PDF 170.38 K (2317) Comment (0) Favorites

      Abstract:杉木是我国特有的主要造林树种,绝大部分分布于长江以南广大中亚热带地区,人工栽培历史悠久.由于传统的砍灌、炼山、整地、植树的更新方式,直接破坏了森林土壤的枯枝落叶层和表土的物理性质.加之杉木为常绿针叶树,叶片含N成分低,从造林至主伐的漫长生长过程中,林分凋落物少,且不易分解,因而加剧了地表冲刷,林地土壤严重退化,导致二代林生产力急剧下降.众多林业科技工作者曾予以高度关注和研究,并初步讨论了杉木林地土壤退化的原因[1~4].

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