浙江省红层母质发育土壤的酸缓冲性及其在人为利用下的酸化特点

为了解由红层坡地改成梯田后,在稳定的成土环境与施肥条件下土壤酸碱度的变化特点,从浙江省采集了240个不同利用方式和利用时间的红层母质发育的农地土壤样本,探讨了不同类型红层母质发育土壤的酸缓冲性,分析了在水耕和旱耕条件下红层母质发育土壤酸碱度随利用时间的变化特点。结果表明,研究土壤酸缓冲曲线可分为pH值>6.5、pH值介于3.5~6.5之间和pH值<3.5等3个阶段,pH值>6.5和<3.5时,土壤pH值随酸加入量的变化较缓慢,对酸具有较强的缓冲性;pH值介于3.5~6.5时,土壤pH值随酸量增加呈现快速下降的趋势,容易发生土壤酸化。红层母质发育土壤的酸缓冲容量与缓冲强度有很大的变化,分别介于65.09~663.31、38.98~160.61 mmol/kg之间,平均值分别为232.64、81.60 mmol/kg;其酸缓冲容量明显高于自然红壤。土壤酸缓冲容量和土壤酸缓冲强度主要与土壤初始pH值、CaCO_(3)含量、CEC和盐基饱和度有关。水耕和旱耕后的红层母质发育土壤均随利用时间的延长而发生酸化,红紫砂土的pH值下降主要发生在利用时间25 a内,紫砂土的pH值下降主要发生在利用时间25 a后;而酸性紫砂土的pH值持续缓慢地下降,水耕对紫砂土的酸化作用较旱耕更明显,但对红紫砂土和酸性紫砂土的酸化作用比旱耕弱。

亚热带东部稻田土壤酸缓冲性能与酸化特点研究

我国亚热带东部降水丰富、淋溶作用强、稻田复种指数与施肥水平高、酸雨频繁,土壤酸化风险较大,但该区地貌和成土母质多变,土壤酸化行为具有较大的空间异质性。为了解这一地区稻田土壤的酸化规律,以浙江省绍兴市为研究对象,通过室内模拟研究与田间广泛采样分析相结合的方法,探讨了该市稻田土壤酸缓冲性能及土壤酸化的时空变化特点。结果表明,地貌对稻田土壤的酸缓冲性能及土壤酸化有较大的影响,土壤酸缓冲容量平均值:滨海平原(484 mmol/kg)>水网平原(157 mmol/kg)>河谷平原(111 mmol/kg)>丘陵(80 mmol/kg);土壤酸缓冲强度平均值:滨海平原(118 mmol/kg)>水网平原(55 mmol/kg)>河谷平原(45 mmol/kg)>丘陵(35 mmol/kg)。全市稻田土壤pH值在3.30~8.72,多数落在4.5~6.5范围内,占82.71%;土壤平均pH值:滨海平原(7.73)>水网平原(6.00)>河谷平原(5.52)、丘陵(5.56);与第二次土壤普查相比,土壤pH≤5.50的稻田比例已由4.09%增大到42.00%;土壤pH值平均下降了0.36个单位。根据土壤对酸性物质的缓冲作用,可把土壤pH值分为大于或等于6.50、3.50~6.50和小于或等于3.50三段,其中土壤pH值为3.50~6.50时对酸缓冲能力较弱,易发生酸化。研究区稻田土壤酸化同时受自然因素与人为活动的影响,酸化稻田土壤的治理应采取综合措施。

安徽主要土壤酸碱性及其酸缓冲性能研究

为了解安徽省土壤酸碱性分布状况和影响因素、以及未来酸雨可能给土壤带来的酸化影响,选取采集了安徽省不同地理区域4种主要土壤的0～20 cm表层样品,通过收集资料、室内测定和相关性分析研究了土壤酸碱性和酸缓冲容量的大小、分布规律及其影响因素。结果表明,安徽主要土壤pH和酸缓冲容量均呈现由北向南依次递减趋势;pH大小顺序为:潮土>砂姜黑土>水稻土>红壤,土壤酸碱性与年均降水量、交换性铝、交换性酸和水解性总酸度均呈极显著正相关(r2=0.7010～0.9039**);土壤酸缓冲容量大小顺序为:潮土(87.6 mmol/kg)>砂姜黑土(36.4 mmol/kg)>水稻土(29.2 mmol/kg)>红壤(23.0 mmol/kg),土壤酸缓冲容量与土壤pH、土壤阳离子交换量和土壤盐基饱和度均呈极显著正相关(r2=0.7631～0.9494**);由此可见安徽几种主要土壤的酸碱性存在很大差异,土壤基本性质和环境条件强烈影响着土壤酸碱性和对酸的缓冲性能,由此也必然影响着土壤受酸雨影响的后果。

几种越橘栽培基质的酸缓冲性及pH值调节技术研究

[目的]确定不同越橘栽培基质适宜的施S时间和施S量。[方法]研究在设施栽培条件下CK（园土）、A（园土、草炭土1∶1）、B（草炭土）、C（园土、腐叶土1∶1）、D（草炭土、蛭石1∶1）、E（草炭土、腐叶土、蛭石、其他材料3∶3∶3∶1）6种越橘栽培基质施入不同量S后pH值的变化规律。[结果]6种基质pH值的降低主要发生在施S后45 d之内,施S后75~81 d pH值基本达到相对稳定状态,以后随着时间的推移,pH值有小幅度的波动;6种基质中,基质A、B的酸缓冲性最强,基质C较强,其余基质较弱;随着施S量的增大,基质pH值降低幅度逐渐减小。[结论]该研究结果为棕壤地区越橘栽培土壤的改良和pH值调节提供了依据。

不同用量贝壳粉对酸性砖红壤的改良效果

以废弃贝壳为研究对象,粤西砖红壤为供试土壤,采用室内土壤培养的方法,研究高(S3,5 g/kg)、中(S2,1.0 g/kg)、低(S1,0.5 g/kg)3种用量的贝壳粉对酸性砖红壤的改良效果,探究贝壳粉改良酸性砖红壤的效果,以期为粤西滨海地区废弃贝壳利用及酸性砖红壤改良提供理论依据。结果表明,不同用量的贝壳粉对土壤pH、EC、交换性酸和Al3+含量、酸碱缓冲性的影响显著。S3和S2用量的贝壳粉均可显著提高酸性砖红壤的pH,而S1与CK处理间的pH无差异;不同用量贝壳粉均可显著降低土壤的潜性酸含量。整个培养期,S3、S2、S1的土壤交换性酸平均含量较CK分别减少了70%、59%、54%;S1、S2、S3处理的土壤交换性铝平均含量较CK分别减少了66%、76%、78%;S3的土壤酸碱缓冲性显著大于其它处理的;相较CK,S3、S2和S1的平均土壤缓冲容量分别提高12.61、6.39和2.44 mmol/kg。针对粤西沿海砖红壤区,建议回收废弃贝壳,并施用5 g/kg的贝壳粉对酸性砖红壤进行改良,既为废弃贝壳污染环境问题提供了新的解决途径,又可有效降低土壤中的活性酸和潜性酸含量,补充酸性土壤中的钙镁等盐基离子,提高土壤的酸碱缓冲性能。

潮土、红壤和盐碱地障碍消减技术与产能提升模式研究进展

耕地质量建设是保障我国粮食安全的战略需求。我国中低产耕地亟需解决酸化、盐碱、贫瘠、生物功能衰减等问题,全面提升耕地产能。中国科学院南京土壤研究所针对潮土、红壤、盐碱土等主要耕地土类,基于长期观测、研究和示范,明确了土壤质量演变规律和退化调控机制,发展了不同农区耕地质量培育理论和技术体系。针对潮土,阐明了有机质、团聚体和微生物联动的内稳性地力形成机制,研发了农田土壤和作物信息监测的传感设备,集成了厚沃耕层构建与大面积均衡增产模式。针对红壤,揭示了土壤酸缓冲性提升抑酸机制和关键微生物驱动养分转化机制,研发了抑酸抗酸协同技术和红壤大团聚体生物培肥技术,分类创建了江西省耕地生态培肥和产能提升模式。针对盐碱土,阐明了土壤水盐调控伴生氮素迁移转化过程,提出盐渍障碍消减与养分增效协同机理与调控技术,创新了滨海盐碱地和河套灌区次生盐渍化生态治理模式。未来研究重点在耕地质量调查与建设管理、耕地土壤障碍消减与产能提升、土壤健康管理与生态保护3个方面,突破土壤障碍消减技术瓶颈,研发系列调理剂和生物培肥产品,提升区域模式落地率,建立我国耕地质量提升和可持续利用的系统解决方案。

Modeling of titration experiments by a reactive transport model

Acid mine drainage（AMD） is commonly treated by neutralization with alkaline substances.This treatment is supported by titration experiments that illustrate the buffering mechanisms and estimate the base neutralization capacity（BNC） of the AMD.Detailed explanation of titration curves requires modeling with a hydro-chemical model.In this study the titration curves of water samples from the drainage of the As Pontes mine and the corresponding dumps have been investigated and six buffers are selerted by analyzing those curves.Titration curves have been simulated by a reactive transport model to discover the detailed buffering mechanisms.These simulations show seven regions involving different buffering mechanism.The BNC is primarily from buffers of dissolved Fe,Al and hydrogen sulfate.The BNC can be approximated by：BNC = 3（C_（Fe） ＋ C_（Al）） ＋ 0.05C_（sulfate）,where the units are mol/L.The BNC of the sample from the mine is 9.25×10^（-3） mol/L and that of the dumps sample is 1.28×10^（-2） mol/L

Investigation on the Key Factors and the Solution for pH Value Decrease in Carbon Filter in O3-BAC Process＊

An investigation was carried out to eliminate the decrease of effluent pH value in carbon filter in O3-biological activated carbon process. The influence factors were examined in a pilot test, and pH was adjusted in the pilot and waterworks. Results show that the carbon filter is an acid-base buffer system and the activated carbon is the key factor. Chemical functional groups on activated carbon surface present acid-base properties to buffer the water but decrease with time, so that effluent pH value decreases. The effects of ozone dosage, CO2 in the carbon filter, and the filter influent quality are negligible. A new method to adjust pH is developed: the activated carbon is first modified by soaking in sodium hydroxide solution to make its pH reach the desired value, and then the pH value of inflow is controlled to certain value by dosing lime in sand filter influent. The method is economical and effective.

Effect of tumor suppressor in lung cancer-1 on growth inhibition of MG63 cell line

Objective： The aim of this study was to establish the osteosarcoma cell sublines which stably expressing tumor suppressor in lung cancer-1 （TSLC1） gene and evaluate its effect on growth inhibition of human osteosarcoma cell line MG63. Methods： The recombinant plasmid pCI-TSLC1 was stably transfected into MG63 cells with Lipofectamine 2000. The posi- tive clones were developed by selection by G418. Biological characteristics of one of the 6 cell lines which highly expressing TSLC1, namely, the M8T were studied. Cell growth was analyzed with MTT assay. 2 x 10^7cells suspended in 0.2 mL phosphate buffered saline （PBS） were injected into the two flanks of 5-6-week-old female BALB/C nu/nu athymic nude mice. The volumes of subcutaneous of tumor growth were evaluated and calculated by the formula V= Length x Width x Height x 0.5 once a week. Results： The MST cell subline which stably expressing TSLC1 was characterized by Western blot. The genetic stability and purity of M8T cells were stable. TSLC1 significantly suppressed the growth of M8T cells in vitro. Moreover, the tumorigenicity of MST cells was suppressed in vivo. Conclusion： The osteosarcoma cell sublines MST which stably expressing TSLC1 had been successfully established. The ability of growth and metastasis of MST was significantly suppressed both in vitro and in vivo.

Mixed alkaline phosphatase/sphingomyelin monolayer at the air-buffer interface: phase behavior and morphology

The glycosylphosphatidyl inositol(GPI)-anchored proteins are localized on the outer of the plasma membrane and clustered in membrane microdomain known as lipid rafts. Among them, mammalian alkaline phosphatase(AP) is an enzyme widely distributed. So, it has important biological significance to study the combination of AP with lipid monolayer. In our work, the interaction between AP and sphingomyelin has been studied at the air-buffer interface as a biomimetic membrane system by the Langmuir film technique and atomic force microscopy. The surface pressure-area isotherm for the mixed alkaline phosphatase/sphingomyelin monolayer shown the presence of a transition from a liquid-expanded phase to the liquid-expanded/liquidcondensed coexist phase. And the surface compressional modulus suggested the mixed alkaline phosphatase/sphingomyelin monolayer has larger compressibility compared with the pure sphingomyelin monolayer. Besides, according to the micrographs, we inferred when combined with lipid monolayer at the air-buffer interface, the AP molecules formed polymer not multilayer or micelle. And, according to the limiting molecules area of AP, we inferred that 12 AP molecules formed a hexagon polymer unit.

Biocompatible Zr-Al-Fe bulk metallic glasses with large plasticity

In the present study,high-zirconium ternary Zr-Al-Fe bulk metallic glasses(BMGs) with low Young's modulus and good plasticity were developed.Zr75 Al7.5 Fe17.5 BMG exhibits a low Young's modulus of 70 GPa and high Poisson's ratio of 0.403.Pronounced plasticity was demonstrated under both compression and bending conditions for the BMGs.Furthermore,the alloys show high corrosion resistance in phosphate buffered solution.The combination of desirable mechanical and chemical properties implies potential for biomedical applications.