土壤中植物有效锰的形态分级

用４种方法测定土壤有效态锰含量,并加以比较和评价,从而确定出最优的土壤有效锰测定方法。研究结果表明,采用一种顺序浸提的方法能比较准确地反映土壤的供锰状况,锰组分及其相应浸提剂为：易溶态锰（０．０５ｍｌ／ＬＣａ（ＮＯ３）２）提取、弱吸附态锰（ｐＨ８．５,ＣａＤＴＰＡ－Ｂ４Ｏ７）、碳酸盐束缚态锰（石灰性土壤,用１．６ｍｏｌ／ＬＨＮＯ３快速浸提）或专性吸附态锰（非石灰性土壤,用１．６ｍｏｌ／ＬＨＮＯ３快速浸提）或专性吸附态锰（非石灰性土壤,ｐＨ４．４,０．０５ｍｏｌ／ＬＣａ（ＮＯ３）２＋０．０５ｍｏｌ／ＬＣｕ（ＮＯ３）２提取）和氧化锰（ｐＨ２．０,０．１ｍｏｌ／ＬＮＨ２ＯＨ．ＨＣｌ）。由盆栽试验辣椒吸收的锰与土壤锰相关分析结果显示,易溶态锰是植物最易吸收的锰,其回归方程为：Ｙ＝－１４．４０９＋２１．６５８Ｘ,ｒ＝０．     

阳阴离子交换膜测定原状土壤K、Zn、Fe的对比研究

用０．１ｍｏｌ／Ｌ ＨＣｌ和０．１ｍｏｌ／Ｌ ＥＤＴＡ－Ｎａ２分别饱和处理阳离子交换膜和阴离子交换膜，对比研究春测定原状土壤剖面微区中Ｋ．Ｚｎ和Ｆｅ的释放速率。结果表明，阳离子交换膜提取的Ｋ和Ｆｅ分别能反映土壤速效Ｋ和水溶态与交换态Ｆｅ的释放速率，阴离子交换膜能同时测定土壤有效Ｚｎ和Ｆｅ的释放速率。     

土壤中有效态重金属Cd Hg提取方法研究

通过采用不同土液比、浸提时间、浸提剂等,研究了不同条件下对提取土壤中Ｃｄ、Ｈｇ含量的影响,及各种条件下提取量与小麦吸收相关关系。结果表明,在褐土上土液比１：１２．５,浸提时间６０ｍｉｎ,１ｍｏｌ／Ｌ ＮＨ４ＯＡｃ浸提剂提取量表示土壤有效态Ｃｄ量较为合适;土液比１：１０,浸提时间３０ｍｉｎ,０．１ｍｏｌ／Ｌ ＣａＣｌ２浸提取量表示土壤有较态Ｈｇ量较为合适。     

HGMS技术与NaOH溶液浓缩土壤铁锰氧化物的效果比较

以我国中南地区几种土壤和土壤锰结核为材料，比较了高梯度磁分选仪与５ｍｏｌ．ｌ＾－１ＮａＯＨ溶液对土壤铁锰氧化物的浓缩效果。结果表明：（１）以１：１型高岭石为主的土样，经５ｍｏｌ．Ｌ＾－１ＮａＯＨ溶液处理后，其氧化铁浓缩倍数高于ＨＧＭＳ处理后的样品，以２：１型层状酸盐矿物为主的土壤浓缩倍数则相反。（２）ＨＧＭＳ处理浓缩土样锰结核中的锰氧化物，其浓缩倍数比５ｍｏｌ．Ｌ＾－１ＮａＯＨ溶液处理的低；但前者     

被土壤吸附的六价铬的最佳提取剂的选取

通过研究土壤中磷酸盐与Ｃｒ（Ⅵ）的竞争吸附作用，查明０．１ｍｏｌ／ＬＫＨ２ＰＯ４－Ｋ２ＨＰＯ４溶液是提取被土壤吸附的Ｃｒ（Ⅵ）的最佳提取剂。     

土壤有机矿质复合体研究 Ⅶ．土壤结合态腐殖质的形成特点及其结合特征

本文系统剖析了熊毅－傅积平改进区分的土壤结合态腐殖质的形成特点，胡，富组成及其结合特征。结果表明：（１）用０．１ｍｏｌ／ＬＮａＯＨ及０．１ｍｏｌ／ＬＮａＯＨ＋０．１ｍｏｌ／ＬＮａ４Ｐ２Ｏ７混合液连续浸提的松结态（Ｈ１）和稳结态（Ｈ２）腐殖质所占的比例随土壤ｐＨ升高分别呈减少和增加趋势。统计分析显示Ｈ１与游离态铁，铝呈极显著的正相关，与交换性钙呈极显著负相关，Ｈ２则与交换性钙呈极显著正相关，而与游离     

田间低矿化水灌溉的土壤盐碱化过程的探讨

本文探讨了田间低矿化水灌溉的土壤盐碱化生态过程，结　果表明：无论在水平方向还是垂直方向上，随着灌溉水矿化度的增加，带入土体中的ＮａＨＣＯ３增多，从而引起土壤ｐＨ，全盐，ＨＣＯ３－，ＥＳＰ及ＳＡＲ逐渐升高．因灌溉水是以ＮａＨＣＯ３　为其主要成分，除Ｎａ＋、ＨＣＯ３－增多外，其余Ｃａ２＋、Ｍｇ２＋、Ｃｌ－、ＳＯ４　２－总量变化不大．小麦采用畦灌的灌水量比玉米的埯灌大得多，带入的盐碱物质相应　增多，造成盐碱化的速度快于玉米田．在田间条件下，盐化和碱化的安全灌溉水矿化度分别　为２．５ｇ／Ｌ和１．５ｇ／Ｌ．     

砷化镓和其它砷化物对大豆种子萌发和异柠檬酸裂解酶（ICL）…

以砷化物为污染源，研究砷对大豆种子萌发及生理活性物质的影响。结果表明：砷化镓（ＧａＡＳ）和砷酸钠（Ｎａ３ＡｓＯ３三个砷和Ｎａ２ＨＡｓＯ４五价砷）对大豆种子萌发的影响，在五价砷（ＧａＡｓ和Ｎａ２ＨＡｓＯ４）１－５ｍｇ／Ｌ，三价砷０．１－１ｍｇｍ／Ｌ对大豆萌发育促进作用，随着浓度提高，发芽率有所下降，五价砷５０ｍｇ／Ｌ和三价砷１０ｍｇ／Ｌ显著受抑制；五价砷５００ｍｇ／Ｌ和三价砷１００ｍｇ／Ｌ种子萌发全     

原子吸收分光光度法测定植株中钙,镁的几种样品前处理方法的比较

本文比较了原子吸收分光光度法测定植株中钙、镁的三种样品前处理方法：干灰化法、１ｍｏｌ／Ｌ ＨＣｌ振荡提取法（振荡法）和１ｍｏｌ／Ｌ ＨＣｌ静止浸泡提取法（浸泡法）。结果表明，振荡法和浸泡法对钙的测定结果平均分别为干灰化法的１０１％和９２．０％，对镁的测定结果平均分别为１０３％和９７．６％。振荡法和浸泡法与干灰化法之间不存在显著性差异（α＝０．０５），它们之间有极显著的正相关性（相关系数在０．９９以     

出芽短梗霉菌株紫外诱变及其发酵条件优化

本研究应用紫外（ＵＶ）随机诱变获得了两株多糖产量高,色素低的出芽短梗霉突变株ＺＹ０４７和ＺＹ０７３,其产量分别为１５．１５和１４．２２ｍｇ／ｍＬ。发酵状况大大改善,产生大量的膨大细胞和厚垣孢子,通过短梗霉的培养基适宜碳氮化和发酵条件,获得优化的培养基方案为：蔗糖５％,ＫＨ２ＰＯ４０．５％,ＮａＣｌ０．１％,ＭｇＳＯ４．７Ｈ２Ｏ０．０２％,（ＮＨ４）２ＳＯ４０．０３％,酵母浸出粉０．０９％,优化的发     

Organic Amendment Effects on the Transformation and Fractionation of Aluminum in Acidic Sandy Soil

Addition of organic amendments can alleviate the level of aluminum (Al) phytotoxicity in acid soils by affecting the nature and quantity of Al species. This study evaluated the transformation of Al in an acidic sandy Alaquod soil amended with composts (10 and 50 g kg^?1 soil of yard waste, yard + municipal waste, GreenEdge^®, and synthetic humic acid) based on soil Al fractionation by single and sequential extractions. Though the organic compost amendments increased total Al in soil, they alleviated Al potential toxicity in acidic soil by increasing soil pH and converting exchangeable Al to organically bound and other noncrystalline fractions, stressing the benefits of amending composts to improve acid soil fertility. The single‐extraction method appears to be more reliable for exchangeable Al than sequential extraction because of the use of nonbuffered pH extract solution.     

Fractionation of extractable aluminum in acid soils: A review and a proposed procedure

Abstract

Different forms of soil aluminum (Al) are involved in the retention of anions and cations, phytotoxicity of Al in acid soils, CEC reduction and soil physical properties such as aggregate stability and water infiltration. Therefore it is desirable to quantify the different forms of Al in soil especially acidic soils. A rationale was developed from a literature survey to identify the following fractions of Al: (a) exchangeable quantified by 1M KC1 extraction; (b) organic bound quantified by 0.1M CuCl₂ + 0.5M KCl extraction; (c) sorhed Al extractable with 1M NE₄OAc at pH 4.0; (d) amorphous Al oxide and hydroxide and amorphous aluminosilicates (if present) extractable with 0.2M ammonium oxalate at pH 3.0; and (e) interlayered Al extractable with 0. 33M sodium citrate at pH 7.3. Pools (a), (b), and (c) are extracted sequentially. Amorphous Al oxide and hydroxide (pool d) is calculated from ammonium oxalate extractable Al minus (a + b + c). Interlayered Al is calculated from sodium citrate extractable Al minus ammonium oxalate extractable Al. The latter two extractions are done on separate subsamples of soils. From preliminary studies and data for 13 soil samples it is suggested that this fractionation of soil Al is more meaningful than that obtained by the KCl ‐> K₄P₂O₇ ‐> ammonium oxalate > citrate‐bicarbonate‐dithionite extraction sequence.     

Assessment of potentially reactive pools of aluminum in Andisols using a five-step sequential extraction procedure

A five-step sequential extraction procedure was developed for the partitioning of soil aluminum (Al) into five fractions: exchangeable, weakly organic bound, strongly organic bound, inorganic non-crystalline and crystalline. The results obtained by the sequential extraction method for Al were compared with those estimated from single extractions using identical operating conditions applied in each individual sequential fraction. The Al content in the extracts was measured by inductively coupled plasma optical emission spectrometry. The results indicated that the first four steps [potassium chloride (KCl), copper chloride (CuCl₂), sodium pyrophosphate (Na₄P₂O₇), acid ammonium oxalate ((NH₄)₂C₂O₄)] in the sequential procedure could be as effective as single extraction methods at estimating exchangeable Al, weakly organic bound Al, strongly organic bound Al, and non-crystalline Al. However, the crystalline Al content by sequential procedure was not in agreement with single extraction procedures. Further, the sequential extractions resulted in more consistent estimates of the aluminum/silicon (Al/Si) molar ratio and allophane and crystalline Al contents than single extractions method. Results of X-ray diffraction on the soil samples confirm the presence of appreciable amounts of at least three types of crystalline minerals, including gibbsite, vermiculite or halloysite. Our result implies that the sequential method can be more reliable in estimating the various Al forms in Andisols.     

茶园土壤pH变化对土壤中铝特性的影响

土壤中铝的毒性强弱取决于铝的形态。为了解茶园土壤中铝的特性,以江苏省7个长期定位观测茶园为研究对象,采用化学连续提取法测定不同条件下土样中不同形态的铝含量,研究茶园土壤pH升高或降低过程中铝的形态转化及其影响因素。结果表明,茶园土壤在酸化过程中活性铝溶出明显增强,不同形态的铝含量有明显差异,依次为腐殖酸铝(Alh)铝的水合化物和氢氧化物(Aloh)交换态铝(Alex)有机态铝(Alo)水溶态铝(Alw)无机吸附态铝(Alino);土壤pH、有机质和酸容量是影响铝形态的重要因素;茶园土壤酸化过程中铝的水合化物和氢氧化物、无机吸附态铝以及水溶态铝会转化为交换态铝。土壤pH升高,交换态铝转化成羟基铝;有机结合态铝会影响其他铝形态的转化,腐殖酸铝在土壤pH升高时转化为铝的水合化物和氢氧化物。     

Aluminum Forms in Solid Phase of Soils Developed over Schists as a Function of Land Use

ABSTRACT

Land use may modify certain soil properties while soil physicochemical characteristics can influence metal partitioning in soils. Therefore, the total content and various forms of aluminum (Al) in solid phase of schist-developed topsoils (0–20 cm) in NW Spain under different land uses (i.e., forest, pasture, and cultivation) were evaluated to identify the Al-bearing phases. Aluminum fractionation was performed, using a six-step sequential extraction procedure with ammonium acetate, hydroxylamine hydrochloride, ammonium oxalate in darkness, hydrogen peroxide, ammonium oxalate under ultraviolet radiation, and acid digestion. Mean concentrations of total Al were similar in the soils under three land uses. Mean percentage of the various Al forms in all soils were in the following order: residual fraction > amorphous compounds > crystalline compounds > water-soluble/exchangeable/specifically adsorbed > bound to oxidizable organic matter > manganese oxides. The forest soils contained considerably higher contribution of amorphous compounds (16.3%) to total Al concentration compared with the soils under other two uses (mean about 9%). Maximum mean concentration of exchangeable Al was also observed in forest soils (mean 8.8% of total Al vs. about 4% in pasture soils and cultivated soils); this is attributed to lower pH and higher organic matter content of the forest soils. Thus, this study revealed the impact of land use on the Al-bearing phases and, hence, in its bioavailability to plants.     

Extractability of manganese and iron oxides in typical Japanese soils by 0.5 mol L−1 hydroxylamine hydrochloride (pH 1.5)

We investigated the extractability of manganese (Mn) and iron (Fe) oxides from typical Japanese soils (Entisols, Inceptisols, and Andisols) by 0.5?mol?L^?1 hydroxylamine hydrochloride (NH₂OH-HCl) extraction (pH 1.5; 16?h shaking at 25°C; soil:solution ratio 1:40), referred as to HH_mBCR, which is Step 2 (used for the reducible fraction) of the modified BCR (Community Bureau of Reference) sequential extraction procedure. The HH_mBCR procedure extracted almost all Mn oxides from the non-Andisol samples, but failed to extract a part of the Mn oxides from some Andisol samples. The procedure extracted most short-range ordered Fe oxides from non-Andisol samples, but it extracted only 7.5% and 13% of the short-range ordered Fe oxides from allophanic and non-allophanic Andisol samples, respectively. This remarkably low extractability of Fe oxides suggests that the HH_mBCR method is not suitable for extracting oxide-occluded heavy metals from Andisols. Since the extraction rate of short-range ordered Fe oxides from various soils with the extractant was negatively correlated with the amounts of oxalate- and pyrophosphate-extractable Al even when the variability of the extraction pH was reduced by increasing the soil:solution ratio from 1:40 to 1:500, the extractability of Fe oxides would be negatively affected by the presence of active Al, including allophane/imogolite, amorphous Al, and Al-humus complexes. Because these Al constituents are abundant in Andisols, they would be at least partially responsible for the lower extractability of Fe oxides by HH_mBCR from Andisols.     

Critical pH and exchangeable Al of four acidic soils derived from different parent materials for maize crops

Purpose

The purpose of this study is to determine the critical soil pH, exchangeable aluminum (Al), and Al saturation of the soils derived from different parent materials for maize.

Materials and methods

An Alfisol derived from loess deposit and three Ultisols derived from Quaternary red earth, granite, and Tertiary red sandstone were used for pot experiment in greenhouse. Ca(OH)₂ and Al₂(SO₄)₃ were used to adjust soil pH to target values. The critical soil pH was obtained by two intersected linear lines of maize height, chlorophyll content, and yield of shoot and root dry matter changing with soil pH.

Results and discussion

In low soil pH, Al toxicity significantly decreased plant height, chlorophyll content, and shoot and root dry matter yields of maize crops. The critical values of soil pH, exchangeable Al, and Al saturation varied with soil types. Critical soil pH was 4.46, 4.73, 4.77, and 5.07 for the Alfisol derived from loess deposit and the Ultisol derived from Quaternary red earth, granite, and Tertiary red sandstone, respectively. Critical soil exchangeable Al was 2.74, 1.99, 1.93, and 1.04 cmol_ckg^?1 for the corresponding soils, respectively. Critical Al saturation was 5.63, 12.51, 14.84, and 15.16% for the corresponding soils.

Conclusions

Greater soil cation exchange capacity and exchangeable base cations led to lower critical soil pH and higher critical soil exchangeable Al and Al saturation for maize.

     

贵州铅锌冶炼区农田土壤镉铅有效性评价与预测模型研究

农田土壤重金属的不同活性库分布和土壤-溶液分配模型能够提供重金属的生物有效性和浸出能力等信息,因而在风险评价和修复实践中非常重要。本研究采集毕节铅锌冶炼区30个历史污染农田土壤,同时在贵州省范围内采集5种类型背景土壤制成不同浓度Pb/Cd单一污染土壤;经3个月老化,分别测定由0.43 mol/L HNO_3、0.1 mol/L HCl和0.005 mol/L DTPA提取态表征的重金属反应活性库以及由0.01 mol/L CaCl_2提取态表征的直接有效库;分析铅锌冶炼区农田土壤Cd、Pb不同有效库的分布特征,建立土壤-溶液分配模型,并讨论土壤理化性质的影响。结果表明:历史污染土壤中Cd和Pb的直接有效库占全量比例分别比人工污染土壤低4倍和223倍,然而历史污染土壤Cd和Pb的反应活性库(0.43 mol/L HNO_3提取态)占全量比例要高于相应人工污染土壤中的比例。拓展Freundlich形式吸附方程能够准确描述各提取态表征的Cd和Pb活性库与土壤全量Cd和Pb的关系,尤其0.43 mol/L HNO_3提取方法能够克服土壤理化性质对土壤Cd和Pb提取的影响而与总量建立极显著的相关关系。pH依附性Freundlich吸附方程准确描述了Cd和Pb的总反应活性库分别与土壤溶液Cd和Pb的关系,对于Pb而言,还要考虑土壤有机质和有效磷的影响。本研究可为矿区农田土壤重金属污染评价、修复以及农田有效态标准的推导提供参考。     

Inorganic Phosphorus Fractionation of Highly Calcareous Soils of Iran

Abstract

Highly calcareous soils are abundant in Iran. The calcium carbonate equivalent (CCE) of these soils reach up to 650 g kg^?1. Although phosphorus (P) fertilizer is being widely used in these soils, little information, if any, is available about P status in such soils. The objectives of this study were to 1) determine inorganic P forms in 18 surface soils of southern Iran, 2) study P readsorption during different stages of fractionation schemes, 3) assess the ability of NaOH to extract aluminum (Al)‐P, and 4) evaluate the relationships between P availability indices and inorganic P forms. Eighteen soil samples with a wide range of physicochemical properties were selected for this study. Inorganic P forms was determined by sequential extraction with NaHCO₃, NH₄OAc, NH₄F, NaOH, citrate dithionite (CD), and H₂SO₄, which are referred to as Ca₂‐P, Ca₈‐P, Al‐P, Fe‐P, occluded P (O‐P), and Ca₁₀‐P. Phosphorus readsorption in different stages was determined by 1 M MgCl₂. Furthermore, a fractionation scheme without an NH₄F step was used to evaluate the ability of NaOH to extract Al‐P. NaHCO₃ (Olsen‐P) and MgCl₂‐extractable P (Exch‐P) were regarded as P-availability indices. The abundance of different P forms was in the order Ca₂‐P<Fe‐P<Al‐P<O‐P<Ca₈‐P<Ca₁₀‐P. Ca₂‐P was highly correlated with Olsen‐P and Exch‐P. Ca₂‐P, Olsen‐P, and Exch‐P showed a relationship with CCE, citrate–bicarbonate–dithionite extractable Fe (Fe_d), and Al (Al_d). Phosphorus readsorption appeared to be important only in the Ca₈‐P step, and the content of readsorbed P was related to Ca₈‐P, CCE, and clay content of the soils. In the present study, Al‐P and Fe‐P accounted for 10 and 5% of the sum of the inorganic P fractions, respectively, and Fe‐P showed a strong relationship with Fe_o, whereas Al‐P showed a significant relationship with oxalate‐extractable Al (Al_o) and Al_d. It was found that one extraction with NaOH is not a good indicator for Fe‐ and Al‐P, and the ability of NaOH to extract Al‐P was reduced with increase in Al‐P content.     

单宁酸对不同pH茶园土壤中活性铝形态分布的影响

采集云南省普洱市和江西省南昌县两地典型的茶园土壤,通过添加HCl和Ca(OH)2调节土壤pH,研究不同pH(3.0、3.5、4.0、4.5)茶园土壤添加0.4 mmol·kg 1、2.0 mmol·kg 1、4.0 mmol·kg 1、8.0 mmol·kg 1、12.0 mmol·kg 1单宁酸后,活性铝形态交换态铝(Al3+)、单聚体羟基铝[Al(OH)2+、Al(OH)+2]、酸溶无机铝[Al(OH)03]和腐殖酸铝[Al-HA]的分布特征。结果表明:单宁酸添加量为0~0.4 mmol·kg 1和0~2.0 mmol·kg 1时,江西南昌和云南普洱茶园土壤中交换态铝随土壤pH的增加呈明显下降趋势,而羟基态铝、酸溶无机铝和腐殖酸铝呈逐渐上升趋势;当单宁酸浓度增至2.0 mmol·kg 1以上时,随土壤pH的增加,单宁酸对活性铝释放的抑制作用增强,各形态活性铝含量都较低,且不同pH处理土壤间的差异不显著。0~20 cm土层土壤与20~40 cm土层土壤变化规律大致相似,总体上看,下层土壤活性铝总量高于上层。云南普洱茶园土壤活性铝总量明显高于江西南昌的茶园土壤。相关分析表明,0~20 cm土层土壤中,pH与羟基态铝、腐殖酸铝、土壤酸碱缓冲容量(pHBC)呈正相关(r=0.796,P0.01;r=0.960,P0.01;r=0.852,P0.01);pHBC与交换态铝、羟基态铝呈负相关(r=0.904,P0.01;r=0.645,P0.05),而与腐殖酸铝呈正相关(r=0.795,P0.01)。同时,单宁酸加入浓度为0~0.4 mmol·kg 1时,土壤pH明显上升,之后随着单宁酸加入浓度的增加土壤pH持续下降,土壤pH(YpH)与单宁浓度(CDN)在此阶段基本符合方程:YpH=0.04CDN+3.82(R2=0.95,P0.01)的线性变化趋势,在单宁酸浓度达到8.0~12.0 mmol·kg 1时,土壤pH基本不再变化。