中国福建省土壤的主要粘土矿物

The clay minerals of more than 200 soil samples collected from various sites of Fujian Province were studied by the X-ray diffraction method and transmission electron microscopy to study their distribution and evolution.Montmorillonite was found in coastal solonchak,paddy soils derived from marine deposit,lacustrine deposit and river deposit,and some lateritic red soil,red soil and yellow soil with a low weathering degree.Chlorite existed mainly in coastal solonchak and paddy soil developed from marine deposit.1.4nm intergradient mineral appeared frequently in yellow soil,red soil and lateritic red soil.The content of 1.4nm intergradient mineral increased with the decrease of weathering degree from lateritic red soil to red soil to yellow soil.Hydrous micas were more in coastal solonchak,paddy soils derived from marine deposit,lacustrine deposit and river deposit.and puple soil from purple shale than in other soils.Kaolinte was the most important clay mineral in the soils iun this province.The higher the soil weathering degree,the more the kaolinite existed.From yellow soil to red soil to lateritic red soil,kaolinite increased gradually,Kaolinite was the predominant clay mineral accompanied by few other minerals in typical lateritic red soil. Tubular halloysite was a widespread clay mineral in soils of Fujian Province with varying quantities.The soil derived from the paent rocks rich in feldspar contained more tubular halloysite.Spheroidal halloysite was found in a red soil and a paddy soil developed from olivine basalt gibbsite in the soils in this district was largely“primary gibbsite” which formed in the early weathering stage.Gibbsite decreased with the increase of weathering degree from yellow soil to red soil to lateritic red soil.Goethite also decreased in the same sequence while hematite increased.     

Effect of low-molecular-weight organic acids on Cl- adsorption by variable charge soils

Low-molecular-weight (LMW) organic acids exist widely in soils and have been implicated in many soil processes.The objective of the present paper was to evaluate effect of two LMW organic acids, citric acid and oxalic acid, on Cl^- adsorption by three variable charge soils, a latosol, a lateritic red soil and a red soil, using a batch method. The results showed that the presence of citric acid and oxalic acid led to a decrease in Cl- adsorption with larger decreases for citric acid. Among the different soils Cl- adsorption in the lateritic red soil and the red soil was more affected by both the LMW organic acids than that in the latosol.     

Preliminary Study on Element Leaching and Current Soil-Forming Process of Red Soils

The leaching characteristics and the element concentration in soil solution of red soils derived from sandstone,granite,Quaternary red clay and basalt have been studied in the Red Earth Ecological Experimental Station,Academia Sinica,using 12 lysimeters.Results obtained show that the element leaching process of red soils occurs mainly from January to the beginning of July annually.The elements with higher concentration in leaching solution of red soils are Si,Ca,Na,K,Mg,and N.The desilication and the leaching process of base cations occur simultaneously in the red soils.Using the first order differential equation and measured parameters of Si leaching,the leaching models of Si for red soils derived from different parent materials are constructed.The leaching process of Si is simulated with the models.Both the absolute and relative ages of red soils derived from different parent materials are discussed based on the simulation result.On the basis of element leaching,composition of soil solution and thermodynamics,the current soil-forming process is discussed.According to the phase diagram,the kaolinization is prevailing in the current formation of different red soils.     

中国亚热带土壤的1.4nm过渡矿物: 综述

This paper is a review of some advances in the studies on 1.4-nm intergrade mineral of soils in subtropical China. 1)1.4-nm intergrade mineral occurs ubiquitously in soils of subtropical China. The 1.4-nm mineral in red soil and yellow soil is mainly 1.4-nm intergrade mineral, and in acidic yellow-brown soil (pH < 5.5) is vermiculite alone or 1.4-nm intergrade mineral together with vermiculite. The distribution and the content of 1.4-nm intergrade mineral in the mountain soils are more widespread and higher than those of the corresponding soils in horizontal zone. 2) The interlayer material of 1.4-nm intergrade mineral in these soils appears to be hydroxy-A1 polymers instead of hydroxy-Fe, proto-imogolite or kaolin-like material. There is a significant positive correlation between A1 amount extracted from the soil with sodium citrate after DCB extraction and pH value of the citrate solution after the extraction. The citrate can also extract a certain amount of silicon from the soil, but the silicon may not come from interlayer of 1.4-nm intergrade mineral. 3) It was seldom studied that either vermiculite or smectite did the natural 1.4-nm intergrade mineral come from in soil, or it was commonly thought to come from vermiculite. A recent report has revealed that it can come from smectite. There are some different behaviors between the 1.4-nm intergrade mineral derived from vermiculite and that from smectite. For example, they exert different influences on the formation of gibbsite. The 1.4-nm intergrade mineral derived from smectite may promote the formation of gibbsite in the yellow soil. 4) The type of 1.4-nm minerals in soils. i.e., vermiculite or 1.4-nm intergrade mineral, may be significant to soil properties, such as soil acidity, exchangeable Al, electric charge amount and specific surface area. Therefore, the management for the soil in which 1.4-nm mineral is mainly 1.4-nm intergrade mineral or vermiculite should be dealt with differently.     

Adsorption of Phosphate on Variable Charge Soils

The study about the adsorption of phosphate on four variable charge soils and some minerals revealed that two stage adsorption appeared in the adsorption isotherms of phosphate on 4 soils and there was a maximum adsorption on Al-oxide-typed surfaces between pH 3.5 to pH 5.5 as suspension pH changed from 2 to 9, but the adsorption amount of phosphate decreased continually as pH rose on Fe-oxide typed surfaces. The adsorption amount of phosphate and the maximum phosphate adsorption pH decreased in the order of yellow-red soil > lateritic red soil > red soil > paddy soil, which was coincided with the content order of amorphous Al oxide. The removement of organic matter and Fe oxide made the maximum phosphate adsorption pH rise from 4.0 to 5.0 and 4.5, respectively. The desorption curves with pH of four soils showed that phosphate desorbed least at pH 5. Generally the desorption was contrary to the adsorption with pH changing.     

Composition and Characteristics of Organo—Mineral Complexes of Red Soils in South China

The objective of the present study is to reveal the composition and characteristics of organo-mineral complexes in red soils (red soil,lateritic red soil and latosol) of south China in terms of chemical dissolution and fractional peptization methos.In the combined humus,most of the extractable humus could dissolve in 0.1 M NaOH extractant and belonged to active humus (H1),and there was only a small amount of humus which could be further dissolved in 0.1 M Na4P2O7 extractant at pH 13 and was stably combined humus (H2).The H1/H2 ratio ranged from 3.3 to 33.8 in red soils,and the proportions of both H1 and total extractable organic carbon (H1 H2) in total soil organic carbon and the ratios of H1 to H2 and H1 to (H1 H2) were all higher in lateritic red soil and latosol than in red soil.The differences of combined humus composition in various red soils were directly related to the content of Fe and Al oxides.In organo-mineral complexes,the ratio of Na-dispersed fraction (G1) to Na-ground-dispersed fraction (G2) was generally smaller than 1 for red soils,but there was a higher G1/G2 ratio in red soil than in lateritic red soil and latosol.G1 fraction had a higher content of fulvic acid (FA),but G2 fraction had a higher content of humic acid (HA).The ratios of H1 to H2 and HA to FA were higher in G2 than in G1.The differences in the composition and activity of humus between G1 and G2 fractions were related to the content of free Fe and Al oxides.The quantities of complex Fe and Al,the Fe/C and Al/C atomic ratios were higher in G2 than in G1,and the ratio of Al/C was much higher than that of Fe/C.It may be deduced that aluminum plays a more important role than iron in the formation process of organo-mineral complexes in red soils.     

草酸对土壤和矿物中钾素的释放规律研究

Oxalic acid plays an important role in improving the bioavailability of soil nutrients. Batch experiments were employed to examine the influences of oxalic acid on extraction and release kinetics of potassium （K） from soils and minerals along with the adsorption and desorption of soil K^＋. The soils and minerals used were three typical Chinese soils, black soil （Mollisol）, red soil （Ultisol）, and calcareous alluvial soil （Entisol）, and four K-bearing minerals, biotite, phlogopite, muscovite, and microcline. The results showed that soil K extracted using 0.2 mol L^-1 oxalic acid was similar to that using 1 mol L^-1 boiling HNO3. The relation between K release （y） and concentrations of oxalic acid （c） could be best described logarithmically as y = a ＋ blogc, while the best-fit kinetic equation of K release was y = a ＋ b√t, where a and b are the constants and t is the elapsed time. The K release for minerals was ranked as biotite 〉 phlogopite 〉〉 muscovite 〉 microcline and for soils it was in the order： black soil 〉 calcareous alluvial soil 〉 red soil. An oxalic acid solution with low pH was able to release more K from weathered minerals and alkaline soils. Oxalic acid decreased the soil K^＋ adsorption and increased the soil K^＋ desorption, the effect of which tended to be greater at lower solution pH, especially in the red soil.     

可变电荷土壤对酸雨敏感度的影响因子

The sensitivity of a large number of variable charge soils to acid rain was evaluated through examining pH-H₂SO₄ input curves. Two derivative parameters, the consumption of hydrogen ions by the soil and the acidtolerant limit as defined as the quantity of sulfuric acid required to bring the soil to pH 3.5 in a 0.001mol L^-1 Ca(NO₃)₂ solution, were used. The sensitivity of variable charge soils was higher than that of constant charge soils, due to the predominance of kaolinite in clay mineralogical composition. Among these soils the sensitivity was generally of the order lateritic red soil > red soil > latosol. For a given type of soil within the same region the sensitivity was affected by parent material, due to differences in clay minerals and texture. The sensitivity of surface soil may be lower or higher than that of subsoil, depending on whether organic matter or texture plays the dominant role in determining the buffering capacity. Paddy soils consumed more acid within lower range of acid input when compared with upland soils, due to the presence of more exchangeable bases, but consumed less acid within higher acid input range, caused by the decrease in clay content.     

不同种类中国杉对土壤养分状况的影响

The effects of different types of Chinese fir stand,including those with varous composition (pure and mixed),in various cropping systems (first and continuous cropping system)and at different ages,on the nutrient status of soils the hilly regions of southern Anhui Province were studied by means of ecological sequential comparison on the basis of similar climate and soil type.The work was carried out in the Xiaoxi Forest Farm of Jingxian County and the Caijiaqiao Forest Farm of Jingde Coundy,where the soil is parayellow soil derived from phyllite and sandstone,The results revealed that with the increase of age,Chinese fir pure stand could accumulate organic matter and nitrogen in the soil but it resulted in decreasing of soil pH and base ions(especially Ca^2 ) compared to its mixed stand with broad-leaf trees such as Chinese sassafras,In order to improve the soil fertility,It would be better to mix Chinese fir with broad-leaf trees when afforestation In the management of Chinese fir pure stand,base compounds and phosphates should be added to the soil for mintaining soil fertility and raising and raising forest productivity.     

Adsorption of Acrylonitrile on Some Soils and Minerals from Aqueous Solutions

Equilibrium and kinetic studies have been made on the adsorption of acrylonitrile(CH2=CHCN) on three soils and four minerals from aqueous solutions.It was shown that the organic matter was the major factor affecting the adsorption process in the soils.The conformity of the equilibrium data to linear type(one soil) and Langmuir type(two soils) isotherms indicated that different mechanisms were involved in the adsorption.This behavior appears bo be related to the hydrophobicity of soil organic matter due to their composition and E4/E6 ratio of humic acids.The adsorption kinetics were also different among the soils,indicating the difference in porosity of organic matter among the soils,and the kinetics strongly affected the adsorption capacity of soils for acrylonitrile.Acrylonitrile was slightly adsorbed from aqueous solutions on pyrophyllite with electrically neutral and hydrophobic nature,and practically not on montmorillonite and kaolinite saturated with Ca.However,much higher adsorption occurred on the zeolitized coal ash,probably caused by high organic carbon content(107g/kg).     

共存阳离子（Ca、Zn、K）对土壤镉有效性的影响

采用盆栽与吸附试验,研究了镉污染赤红壤上,施用相同摩尔浓度的钙、钾与锌对小油菜生物量、镉吸收量及土壤镉吸附的影响。结果表明,低和高镉污染赤红壤上,施用锌明显增加小油菜地上部生物量,较对照分别增产21.1%和7.82%。不同阳离子（钠、钙、钾和锌离子）共存改变土壤吸附镉能力的程度不同,与钠体系相比,钙、钾和锌体系中土壤镉吸附量分别降低65.6%、72.0%和96.9%,共存离子降低土壤镉吸附量的次序为锌离子〉钾离子和钙离子,锌离子的影响最为明显。高镉污染赤红壤上,钙和钾使小油菜吸镉量分别增加5.5%和14.4%,低于低镉污染赤红壤上钙和钾使小油菜吸镉的增加量（分别为16.6%和19.6%）;锌明显降低小油菜吸镉量,高和低镉污染赤红壤上,较对照分别减少45.8%和35.0%。3种阳离子与镉共存时,对土壤镉生物有效性的影响差异取决于竞争吸附与竞争吸收的大小,其机制有待进一步探讨。     

离子强度和三氧化物对土壤吸附Bt毒素的影响

Chemical reactions and fate of the toxins of Bacillus thuringiensis(Bt) in the soil environment are causing increasing concerns due to the large-scale cultivation of transgenic Bt plants.In this study,the effect of ionic strength(0-1 000 mmol kg 1) adjusted by NaCl or CaCl 2 on adsorption of Bt toxin by a lateritic red soil,a paddy soil and these soils after chemical removal of organic-bound or free Fe and Al oxides,as well as by pure minerals(goethite,hematite and gibbsite) which are widespread in these soils,were studied.The results indicated that when the supporting electrolyte was NaCl,the adsorption of Bt toxin by the lateritic red soil and paddy soil increased rapidly until the ionic strength reached 250 mmol kg 1 and then gradually slowed down with the increase of ionic strength;while in case the supporting electrolyte was CaCl 2,the adsorption of Bt toxin enhanced significantly at low ionic strength(< 10 mmol kg 1) and then decreased as the ionic strength increased.The adsorption of Bt toxin by the tested minerals and soils after the removal of organic-bound or free Fe and Al oxides also increased with increasing ionic strength controlled by NaCl.Removing organic-bound Fe and Al oxides obviously increased the adsorption of Bt toxin in the tested soils.Differently,removing free Fe and Al oxides increased the Bt adsorption by the paddy soil,but decreased the adsorption by the lateritic red soil.The study indicated that the varieties of ionic strength and the presence of Fe and Al oxides affected the adsorption of Bt toxin by the soils,which would contribute to the further understanding of the fate of Bt toxin in the soil environment and provide references for the ecological risk assessment of transgenic Bt plants.     

Red soil chemistry and mineralogy reflect uniform weathering environments in fluvial sediments, Taiwan

Purpose

Information on the physicochemical properties, mineral species and micromorphology of lateritic soils and gravel soil layers in paleo-environmental soil profile is severely lacking. Red soil profile of the Taoyuan terrace was employed to demonstrate its different extents of lateritic weathering. The objectives of this study were to compare the physicochemical properties of lateritic soils and gravel soil layers and identify using conventional and synchrotron X-ray diffraction (XRD) analyses mineral species in nanoparticles separated by automated ultrafiltration device (AUD) apparatus.

Materials and methods

Soil samples were collected from paleo-environmental lateritic soils. Soil samples were examined using elemental analysis, conventional and synchrotron XRD analyses, high gradient magnetic separation, separation and collection of nanoparticles by AUD apparatus, and transmission electron microscopy (TEM).

Results and discussion

The soil pH, redness index, quantities of free Al- and Fe-oxides (Al_d and Fe_d), and clay content of lateritic soils are higher than those of gravel soil layers. Illite, kaolinite, gibbsite, quartz, goethite, and hematite were identified in clay fractions and nanoparticles by conventional and synchrotron XRD analyses. TEM images show presence of hematite nanoparticles on the surface coating of kaolinite nanoparticles and aggregated hematite nanoparticles overlapping the edge of a kaolinite flake in a size range of 4?C7?nm. Synchrotron XRD techniques are more straightforward and powerful than conventional XRD with random powder methods for identifying nanoparticles in red soils, particularly for illite, kaolinite, goethite, and hematite nanoparticles. According to chemical compositions of clay fractions and red soil features in the Taoyuan terrace, these red soils can be taken as lateritic red earths or red earths.

Conclusions

This work suggests that physicochemical properties, mineral species, and micromorphology of red soil at all depths can shed light on the extent of paleo-environmental lateritic weathering.     

新垦赤红壤结构特性的演化

本文探讨新垦赤红壤结构特性的变化，定位试验结果表明：在亚热带生物气候条件下垦殖赤红壤，由于耕作管理扰动土壤，将不可避免地产生土壤砂化或粉砂化现象。     

稻作制与有机肥对红壤水稻土微生物及酶活性的影响研究

长期定位试验研究稻作制和有机肥对红壤水稻土微生物数量及酶活性的影响结果表明 ,不同稻作制和有机肥施用量对土壤微生物组成和数量的影响不同。良好的稻作制和适量有机肥可提高土壤酶活性和土壤肥力。     

利用放射性碳对中国变性土的年代确定

Vertisols,which are mainly developed on fluvial and lacustrine deposits and basalt,are extensively distributed in China.66 samples of them for radiocarbon dating were collected across 5 porvinces and 1 autonomous region,ranging from warm-temperate to subtropical and tropical zones in China.The soil organic matter was dated via surface horizon,black soil horizon and dark-colour horizon of the vertisols,whereas carbonate through calcareous concretions and dispersed carbonate in soil profile using radiocarbon method.The present article elucidates the dates of genetic horizons,and of surface and buried vertisols as well.14C dating indicates that the surface vertisols were formed during the end of the late Pleistocene.ca.15600 years ageo.Correlation between depth of sampling and measured 14C age shows that age characteristics of the vertisols of China are close to those of West Germany,Italy,TUrnisia,Australia and Argentina,However,two buried vertisols developed on fluvial and lacustrine deposits were formed during different geological periods,The buried soils in warm-temperate zone were formed in the mid Holocene,while those in subtropics were buried at 12930 years B.P., and formed in the end of the late Pleistocene.     

华南热带土壤养分含量状态及肥力评价

华南热带亚热带地区,广泛分布着红壤、黄壤、赤红壤、砖红壤以及在这些土壤上发育的水稻土.这个地区年平均气温在17-25℃之间,≥10℃的年积温为5000—9500℃,其中赤红壤和砖红壤地区,年平均气温在21℃以上,≥10℃年积温达7100—9500℃之其中赤红壤和砖红壤地区,年平均气温在21℃以上,≥10℃年积温达7100-9500℃之间,年降雨量在1500毫米以上,是我国发展热带、亚热带经济作物和林果木的良好基地,也是发展以水稻为主的粮食作物的好地方^[1,7-9].     

Restoration of surface soil fertility of an eroded red soil in southern China

To ameliorate degraded red soils and restore their productivity, it is necessary to quantitatively assess the effects of different land uses on soil fertility. In this study, surface soil samples (0–20 cm) under different land uses were collected from an 18-year ameliorative experiment site of a eroded red soil in Lanxi county, Zhejiang province of southern China. The status of surface soil fertility was quantified with a ryegrass growth test in the greenhouse and by numerical analysis of twelve important fertility indexes. The soil fertility indexes were grouped into three major factors using a factor analysis, i.e., organic matter-nitrogen-structure, acidity and phosphate. By means of principal component analysis and cluster analysis of these fertility factors, the fertility of the eroded red soil as a function of land use patterns had the following decreased order: vegetable land>paddy field, cropping arable land and ryegrass land>tea garden>citrus garden>forestland>wasteland. The result suggested that organic matter, total N, available N, and water-stable aggregates were the main characteristics for fertility restoration of the eroded red soil. Soil fertility was most rapidly restored where the soil had been used as vegetable land, and least restored when left as wasteland. The results indicated that land use strongly affected the fertility restoration of eroded red soils because of its effect on the input of nutrients and energy, thus determining the speed and direction of soil fertility evolution.     

坡地赤红壤不同利用模式对土壤磷和酶的影响

试验采用广东东莞花岗岩发育的坡地赤红壤为样品进行研究表明 :在坡地赤红壤的 4种利用模式中 ,旱地种植花生 ,荔枝可以有效地改善土壤的酸性 ,提高土壤肥力 ;提高土壤Al-P和Fe -P的含量 ,减少O -P的所占的比例 ,提高坡地赤红壤磷酸盐的有效性 ;增加土壤表层的脲酶和蛋白酶的活性 ,可能使土壤的磷酸酶的活性降低