SO42-和Cl-对稻田土壤养分及其吸附解吸特性的影响

利用长期定位试验 ,比较了长期施用含SO42-和Cl- 化肥 22年后稻田土壤的 pH值、养分状况及其吸附解吸特性。结果表明 ,长期施用含SO42-化肥 ,土壤有机质、速效氮和速效钾的含量较高 ,但全量氮磷钾的含量较低 ;长期施用含Cl- 化肥 ,土壤全量氮磷钾和速效磷的含量较高 ,但pH值相对较低。长期施用含上述二种阴离子的化肥后 ,土壤对H2PO4-的最大吸附量均较大 ,且在Cl- 处理下土壤对H2PO4-吸附的结合能较大 ,而SO42-处理下土壤在同等吸附量时对H2PO4-的解吸量相应较多。长期施用含SO42-的化肥亦使土壤对钾素的供应强度较大 (K0的绝对值较大 )、缓冲能力增强 (AR0值较高 ) ,而长期施用含Cl- 的化肥时则与SO42-相反     

用电导频散法研究Cl-、SO42-和H2PO4-阴离子与土壤的相互作用

本文介绍了采用电导频散装置测量分别含有10^-4mol/LHCl、5×10^-5mol/L H₂SO₄和10^-4mol/L H₃PO₄的黄棕壤、棕壤、黑土和砖红壤悬液(20-30g/kg)的电导频散曲线,频散曲线上均呈现频率范围相当宽的坪区,频散曲线的特性分析结果表明,黄棕壤和棕壤在3种酸溶液中的始散频率(0.6-1kHz)低于黑土悬液(16-28kHz),而砖红壤的始散频率最高(25-47kHz;Cl^-、SO₄^2-和H₂PO₄^-离子与4种土壤的相对亲合力(REC_1.5/REC_tp-1)顺序为Cl^- < SO₄^2- < H₂PO₄^-,在不同土壤之间的顺序则随酸溶液而异.     

Cl-、SO42-在酸性土壤中对铝电极电位的影响及其差异

盐分是土壤腐蚀的一个重要影响因素,业已证明,土壤盐分尤其有Cl^-存在时,能加速土壤腐蚀反应^[1,2]。Cl^-、SO₄^2-是土壤中常见的盐分阴离子,它们不但能破坏金属表面的氧化膜,同时由于Cl^-、SO₄^2-都具有特性吸附能力,有可能直接参与腐蚀反应过程。     

Chemical Behavior of Chromium in Soils: Ⅲ. Mechanism of Cr(Ⅵ) Adsorption by Soils

An analysis of Cr (Ⅵ)-sorbed surface of the soils by using a scanning electron microscope and an electron probe microscope has proved that aluminium is the chief element affecting Cr (Ⅵ) adsoption. As the ionic strength of the solution increased, the amounts of Cr (Ⅵ) adsorbed by goethite and soils decreased. Cr (Ⅵ) adsorption was greatly depressed in the presence of SO₄^2-, WO₄^2-, MoO₄^2-, HPO₄^2- and H₂PO^4- which competed for anion adsorption sites. The depressing extent of these anions was found to follow the sequence: HPO₄^2-, H₂PO^4->MoO₄^2->WO₄^2->SO₄^2->>Cl^-, NO^3-. The amounts of Cr (Ⅵ) desorption varied with different extractants.     

影响土壤镉吸持和解吸的因子

研究了土壤的pH、离子浓度(0.01mol/L、0.05mol/L、0.1mol/L)、阴(阳)离子种类(NO₃^-、Cl^-、OAc^-、SO₄^2-、HPO₄^-及Zn和Pb)及石灰和葡萄糖对土壤镉吸持及其解吸的影响。     

NO-3胁迫下K+、Ca2+对黄瓜幼苗膜质过氧化及活性氧清除酶系统的影响

通过水培试验探讨了NO^-₃胁迫下K⁺、Ca²⁺对黄瓜幼苗膜质过氧化及活性氧清除酶系统的影响。结果表明，在相同NO^-₃浓度胁迫7d后， Ca²⁺浓度越大，膜脂过氧化产物丙二醛(MDA)含量越高，而K⁺浓度越大，电解质相对渗透率越高，由此说明K⁺、Ca²⁺对细胞膜造成伤害的机理不同。黄瓜幼苗活性氧清除酶系统对K⁺、Ca²⁺的响应亦不同，在一定程度上，K⁺和Ca²⁺ 可提高SOD、POD和CAT活性，保护植物免受自由基伤害，继而可增强植物对逆境的适应能力。     

可变电荷土壤对SO42-的吸附

本文研究了三种带可变电荷的红壤在恒定pH和Cl^-离子存在条件下对SO₄^2-的吸附.三种红壤的OH^-释放量分别仅占SO₄^2-吸附量的12%,14%和20%.砖红壤在pH5.0时的电荷变化占所吸附的SO₄^2-的64-82%.作者认为大部分SO₄^2-以置换水合基的方式被吸附.     

不同土地利用方式土壤对铜、镉离子的吸附解吸特征

采用一次平衡法对Cu²⁺、Cd²⁺在城市及城郊农田、林地、草地3种土地利用方式土壤中的吸附解吸过程进行比较研究, 结果表明: Cu²⁺、Cd²⁺在3种土地利用方式土壤中的吸附量均随平衡液浓度的增加而增大, Cu²⁺、Cd²⁺在农田土壤上的吸附量均高于林地和草地土壤。分别用Langmuir和Freunlich两种等温吸附方程对吸附过程进行拟合, 3种土壤对Cu²⁺的吸附过程运用Langmuir方程拟合效果好, 而对Cd²⁺的吸附过程运用Freunlich方程拟合效果更好。Cu²⁺在3种土壤的解吸量大小顺序为农田>林地>草地, Cd²⁺在3种土壤的解吸量大小顺序为农田>草地>林地。两种离子在3种土壤中的动态吸附是个快速反应的过程, 随时间延长, 吸附反应趋于平衡。运用双常数函数方程和Elovich方程能较好地拟合重金属在土壤上的吸附动力学过程。Cu²⁺、Cd²⁺的吸附与土壤黏粒含量、有机质含量、CEC和pH均有关。     

肥液浓度对单膜孔入渗NO-3-N运移特性影响的室内试验研究

该文通过室内入渗试验，研究了不同浓度的单膜孔肥液入渗NO^-₃-N的分布特性。研究表明：不同浓度的膜孔肥液入渗土壤NO^-₃-N浓度的湿润锋运移距离与土壤水分运动的湿润锋一致；肥液浓度越大，相同入渗时间的NO^-₃-N浓度锋运移距离越大，土壤剖面NO^-₃-N浓度最大值越大，相同深度处土壤NO^-₃-N浓度也越大。肥液入渗土壤NO^-₃-N浓度分布特征与湿润体深度符合分段函数模型。供水入渗过程中，NO^-₃-N浓度锋运移距离和浓度最大值均随时间的延长而增大；再分布过程中，NO^-₃-N浓度锋运移距离继续增大，而NO^-₃-N浓度最大值逐渐减小。     

土壤中可变电荷表面磷的解吸特性

本文研究了土壤中可变电荷表面磷的解吸特性。结果表明,磷解吸量与吸附量成正相关,并与直线方程和指数方程拟合。其平均解吸百分数依次为:高岭石(66%)>无定形硅酸铝(60%)>砖红壤粘粒(55%)>>无定形氧化铁(29%)>三水铝石(23%)>>火山灰粘粒(9%)。解吸体系的pH是借对磷酸根质子的解离和表面电荷的影响而制约解吸量。F^-和OH^-离子对磷酸盐化的三水铝石连续解吸的结果表明,磷酸根和氟离子在三水铝石表面的吸附量或剩余量之和均较为接近,这揭示了H₂PO₄^-和F^-离子之间既竞争又相互补充表面空位。它可作为一种区分磷吸附形态和沉淀的定量方法来进一步研究。     

长期施用含硫化肥对稻田土壤养分含量及剖面分布的影响*

在红壤水稻田每年施用等量氮、磷、钾养分条件下,设每年施硫量分别为0、112、604 kg/hm2 3个处理,进行了长期（33年）施硫与不施硫土壤碳、氮、磷、钾、硫等养分含量变化及其在土壤剖面的分布特征和含硫化肥长期施用的生态环境效应的定位试验。结果表明,长期施硫土壤有效硫含量显著升高,并在土壤剖面（0100 cm）上累积; 高硫（HS）、低硫(LS)处理有效硫含量比无硫(NS)处理平均增加85.6%和12.8%; 施硫处理土壤耕层有机质、全氮、全磷含量升高,其中高硫处理土壤有机质、全氮和全磷含量分别比试验开始时增加17.7%、25.6%和250.0%。长期施硫的土壤有机质增加速率显著高于不施硫处理,高硫处理其含量比无硫处理增加了11.5%,说明施用硫肥有利于提高耕层土壤有机质,促进土壤养分累积。在南方红壤硫素养分缺乏的地区,施用硫肥有显著的培肥效应,生产中应重视硫肥的施用。     

伴随阴离子对马铃薯种植冲击土中钾素固持与淋溶的影响

A column study was carried out to assess the influence of accompanying anions on potassium (K) leaching at potato growing sites with different soil textures (sandy loam and clay loam) in northwestern India. Potassium was applied in the top 15 cm layer of soil column at 30 and 60 mg K kg^-1 through different sources having different accompanying anions (Cl^-, SO₄^2-, NO₃^- and H₂PO₄^-). Maximum K was retained in the top 0--15 cm layer with a sharp decrease in K content occurring in 15--30 cm layer of the soil column. The trend was similar for both levels of applied K as well as frequency of leaching and soil type. The decrease of K content in soil column after four leaching events was maximum in case of Khanaura sandy loam, while only minor decrease was observed in Hundowal clay loam when K was applied at 60 mg K kg^-1, indicating higher potential of clay rich soil to adsorb K. In general, the K leaching in presence of the accompanying anions followed the order of SO₄^2- ≤ H₂PO₄^2- < NO₃^- = Cl^-. Highest 1 mol L^-1 CH3COONH4-extractable K was retained when K was applied along with SO42- and H2PO4- anions, and the least was retained when accompanying anion was Cl^-1. The influence of anions was more pronounced in the light textured soil and at high amounts of K application. Higher levels of K application resulted in higher losses of K, especially in sandy loam soil as observed from the leachate concentration. Among the different K sources, the maximum amount of K leaching was noticed in the soil column amended with KCl. After four leachings, the maximum amount of K leached out was 6.40 mg L^-1 in Hundowal clay loam and 9.29 mg L^-1 in Khanaura sandy loam at 60 mg K kg^-1 of soil application through KCl. These concentrations were lower than the recommended guideline of the World Health Organisation (12.00 mg L^-1).     

Effect of ammonium sulfate,ammonium chloride and root‐zone acidity on inorganic ion content of tobacco

Tobacco plants (Nicotiana tabacum L. cv NC82) were supplied with (NH₄)₂SO₄, or NH₄Cl at root‐zone pH of 6.0 and 4.5 in hydroponic culture for 28 days. Dry matter accumulation, total N and C content, and leaf area and number were not affected by the NH₄ ⁺ source or root‐zone pH. Plants supplied with NH₄C1 accumulated up to 1.2 mM Cl g DW^‐1, but accumulated 37% less inorganic H₂PO₄ ^‐ and 47% less SO₄ ^2‐ than plants supplied with (NH)₂SO₄. The large Cl^‐ accumulation resulted in NH₄C1 –supplied plants having a 31% higher inorganic anion (NO₃ ^‐, H₂, PO₄ ^‐, SO₄ ^2‐, and Cl^‐) charge. This higher inorganic anion charge in the NH₄C1‐supplied plants was balanced by a similar increase in K⁺ charge. Plants supplied with NH₄Cl accumulated greater concentrations of Cl^‐ in leaves (up to 5.1% of DW) than plants supplied with (NH₄)₂SO₄ (less than ‐% DW). Despite the high Cl^‐ concentration of leaves in NH₄Cl supplied plants, these plants showed no symptoms of Cl^‐ toxicity. This demonstrates that toxicity symptoms are not due solely to an interaction between high Cl^‐ concentration in tissue and NH₄ ⁺ nutrition. The increase in root‐zone acidity to pH 4.5 from 6.0 did not induce toxicity symptoms.     

Water,NaHCO3−, NaH2PO4− and NaCl-extractable SO42− in acid forest soils

A variety of different methods have been used for the determination of inorganic soil SO₄^2? in the past, which makes it difficult to compare SO₄^2? contents of soils. Sulfate was extracted with the four commonly used extraction solutions 0.5 M NaHCO₃, 0.02 M NaH₂PO₄, 0.1 M NaCl and H₂O from A-, Bw- and Bs-horizons of six acid forest soils. 5 g of field moist soil were percolated with a flow rate of 5 ml/h and percolations were repeated as long as SO₄^2? was detectable in the percolate (> 0.5 mg SO₄·l^?1). NaCl and NaHCO₃ extracted highest amounts of total inorganic SO₄^2? in A-horizons, but NaHCO₃ caused analytical problems. NaHCO₃ and NaH₂PO₄ yielded highest amounts in B-horizons. With the exception of Bs-horizons more than 70% of the total inorganic SO₄^2? was H₂O-soIuble. Thus, if H₂O-soluble SO₄^2? is defined as reversibly bound, the greater part of the inorganic SO₄^2? in the investigated acid forest soils was reversibly bound. This SO₄^2? fraction can potentially be released, if SO₄^2? deposition decreases.     

Effect of slow releasing nitrogen fertilizers on nutrient status across wheat rhizosphere grown on volcanic ash

Abstract

The volcanic ash of the Mount Pinatubo in Philippines was used in this study. The major drawbacks of this ash for growing agricultural crops are nitrogen (N) and iron (Fe) deficiencies with low organic matter contents. The main objective of this study is to investigate the wheat grown on the volcanic ash to and determine the nutrient status across its rhizosphere using a rhizobox system. Either oxamide or polyolefinresin‐coated urea (PORCU) along with potash and phosphate fertilizers was applied to each rhizobox containing the volcanic ash. Plants were grown on the central compartment (CC) of the rhizobox. The nutrient status was examined by the assessment of distribution patterns of NH₄ ⁺‐N, NO₃ ^‐‐N, Ca²⁺, Mg²⁺, K⁺, Cl^‐, SO₄ ^2‐, PO₄ ^3‐, and associated pH. Although NH₄ ⁺‐N in both oxamide and PORCU treatments was accumulated to a somewhat considerable extent of the rhizosphere. The rhizosphere effect was more prominent in oxamide treatment. While NO₃ ^‐‐N concentrations in either of the treatment was low with a mere rhizosphere effect in PORCU treatment and a rugged distribution in oxamide treatment. Dominant anions and cations accumulated in the CC and the near by compartments of oxamide treatment were Cl^‐, SO₄ ^2‐ and Ca²⁺, respectively. In contrast, SO₄ ^2‐ and K⁺ were accumulated in the CC and the adjacent PORCU treated compartments. Thus the overall distribution of nutrients and pH across the wheat rhizosphere was rugged. Despite of this, it seems that with a rugged nutrient distribution and pH, the effects of slow releasing N fertilizers may well ensure the N benefit on plants while growing on the volcanic ash under circumstances of low N content.     

NITROGEN–PHOSPHORUS–POTASSIUM EFFECTS ON FORMS OF SULFUR IN LEAVES AND FRUITS OF CUCUMBER

ABSTRACT

The impact that nitrogen (N), phosphorus (P), and potassium (K) application rates on the sulfur (S) fractions in leaves and fruits of greenhouse-grown cucumbers plants (Cucumis sativus L. cv. Brunex) are presented. The treatments were as follows: N (N1=5 g NO₃NH₄/m², N2=10 g NO₃NH₄/m², N3=20 g NO₃NH₄/m², N4=40 g NO₃NH₄/m²), two levels of P (P1=8 g H₃PO₄/m² and P2=16 g H₃PO₄/m²), and two levels of K (K1=20 g K₂SO₄/m² and K2=40 g K₂SO₄/m²). The foliar and fruit contents were determined for total S, organic S and sulfate. The influence of the N treatments on the total S (St: organic S +sulfate) concentration, proved significant, showing a progressive increase in the leaf and fruit concentrations. In the leaves, the P slightly diminished the St concentration but values in the fruits did not appreciably differ from control. The K dosage did not cause the St concentration to differ from that of P, although in the fruit a slightly lower St concentration appeared in the K2 treatment. The response of the organic-S concentration in the leaves resembled that of St, and thus organic S should not be used as a diagnostic method for S status. In the relationship SO₄ ^2-/St, the SO₄ ^2- concentration proved more influential than did the St form, providing a more accurate representation of the potential status of this nutrient in the plant.     

Ionic equilibria,selectivity and diffusion of cations in soil as influenced by anion additions

Abstract

An experiment was carried under controlled conditions to investigate the influence of the anions, H₂PO₄ ^‐. and Cl on the ionic equilibria, selectivity and effective diffusion of Rb, K, Na, Ca, Mg in two Indiana soils.

Additon of anions to the soils increased the concentration of cations in soil solution. In both the soils receiving H₂PO₄ ^‐, lower cation concentrations were found in the soil solution than in those receiving Cl^‐ . Additon of H₂PO₄ ^‐and Cl^‐ reduced the ion selectivity coefficient, k, for various homovalent (Rb/K, Rb/Na, K/Na, Ca/Mg) and mono‐divalent ion pairs (Rb/Ca, Rb/Mg, K/Ca, K/Mg). In Zanesville soil treatments receiving H₂PO₄ ^‐ had lower k values for mono‐divalent cations than treatments receiving Cl^‐. However, no such conclusions could be drawn for Raub soil. Soils treated with H₂PO₄ ^‐ had higher k values for homovalent cations than Cl^‐ treated soils. The differences in the selectivity of adsorption in these two soils might be attributable to the differences in the type and nature of exchange materials and cation concentrations on the exchange phase.

Addition of H₂PO₄ ^‐ or Cl^‐ enhanced the magnitude of effective diffusion coefficient. (De) of all the cations under considerations. The magnitude of effective diffusion coefficient for cations was lower for H₂PO₄ ^‐ treated soils than Cl^‐ treated soils. Such a reduction in De is related to the reduction in cation concentration in soil solution thereby increasing the buffer capacity for the ions under consideration.     

不同肥料结构对红壤稻田氮素迁移的影响

不同肥料结构对红壤稻田淹水层、不同深度渗漏水、外排水和土壤剖面中氮素的含量、形态及其动态变化的影响研究结果表明 ,各处理淹水层、外排水和渗漏水中NH4+-N含量明显高于NO3--N。淹水层中N的含量 ,水稻生育前期以单施化肥的高 ,约相当于配施有机肥的 1.18～ 1.20倍 ,而水稻生育后期 ,后者为前者的 1.11～ 1.2 1倍。各处理外排水中N素的输出量均以苗期最高 ,单施化肥明显大于配施有机肥。土壤剖面中NH4+-N向下迁移比碱解N更为明显 ,且配施有机肥的远高于单施化肥的 ,而NO3--N则相反。不同深度渗漏水中NO3--N的比例 ,上层 (30cm)低于下层 (50cm) ,随水逸出的N量各处理渗漏水均小于外排水 ;随水输入的N量远低于随水输出的N量 ,且以单施化肥的N亏损最大。水稻未利用的N量也以单施化肥的最大 ,约为配施有机肥的 1.0 9倍。     

Determination of sulfate in soils by reduction with tin and phosphoric acid

Abstract

A rapid and precise method for determination of SO₄ ^2‐‐S in soils is described. It involves the extraction of SO₄ ^2‐ from soils and its reduction to H₂S by a reagent containing Sn and H₃PO₄ and subsequent determination as methylene blue. The results agreed closely with those obtained by reduction with the a reagent containing HI, H₃PO₂, and HCOOH and by ion chromatrography. Tests indicated that, in addition to SO₄ ^2‐, the Sn‐H₃PO₄ reagent reduces certain organic S and reduced inorganic S compounds, but these S compounds are not present in extracts of agricultural soils. By using a bank of 10 distillation units, a single operator can perform 60 analyses in a normal working day.