土壤对铜离子的专性吸附及其特征的研究

供试土壤专性吸附铜的等温线均符合Langmuir方程。红壤吸附量最低,砖红腹与黄泥土最大吸附量相近,但在铜浓度低时砖红壤吸铜量远低于黄泥土,而在高浓度则反之。土壤专性吸附铜是在溶液中Na⁺浓度比Cu²⁺高8.3—100倍条件下,Na⁺离子仍不足以与之竞争的那些专性吸附点所吸持的铜。按其解吸条件区分为松结合铜(可为N NH₄Cl解吸)和紧结合铜(仅能为0.1 N HCl解吸)两种。紧结合铜受平衡溶液铜浓度影响很小,所占据的吸附点对Cu²⁺有较强亲和力。松结合铜则随平衡铜溶液浓度增大而增加,符合Langmuir方程。对于砖红壤和黄泥土,在铜浓度低时紧结合铜>松结合铜;浓度高时则反之。红壤专性吸附铜始终以松结合铜为主。三种土壤比较,紧结合铜是砖红壤>黄泥土>红壤;松结合铜则是黄泥土>砖红壤>红壤。造成这些差别的原因可能与土壤性质、氧化物、有机质和粘土矿物组成等不同有关。用平衡法研究三种土壤专性吸附铜在不同浓度NH₄Cl和HCl溶液中的解吸表明,可进一步区分为三或四种不同的结合状况。红壤对铜吸附容量最小,且最易解吸。     

有机质和陪伴阴离子对土壤吸附Zn的影响

本文研究了土壤有机质和陪伴阴离子对黄棕壤、红壤和砖红壤吸附Zn²⁺的影响。结果表明:土壤有机质含量与吸附Zn²⁺的数量呈正相关;陪伴阴离子对土壤吸Zn²⁺量有显著的制约作用,土壤从ZnCl₂溶液中吸附的Zn²⁺数量高于Zn(NO₃)₂的0.77-1.16倍;△pH值与吸Zn²⁺量呈直线关系。由解吸情况可以判明红壤胶体表面的高能吸附位占的比例明显大于黄棕壤或砖红壤。     

恒电荷土壤及可变电荷土壤与离子间相互作用的研究 Ⅰ.共存离子对NO3-吸附的影响

研究了我国典型3种可变电荷土壤和4种恒电荷土壤在陪伴阳离子分别为K+、Na+、Ca2+时和1mmolL-1KCl、K2SO4支持电解质中NO-3的吸附.结果表明,NO-3吸附量随pH的增加而减小.在添加相同浓度NO-3时,3种可变电荷土壤对NO-3的吸附量顺序为Ca(NO3)2＞KNO3＞NaNO3＞KNO3+KCl＞KNO3+K2SO4;在初始NO-3浓度0.5～5mmolL-1的范围内,吸附量随浓度变化的关系符合Langmuir等温吸附式.由此求出与NO-3吸附结合能有关的常数(K)在不同共存离子存在下数值较小且差异不大,因此认为不同陪伴阳离子和不同伴随阴离子对NO-3吸附的电性机理影响不大,只是改变了土壤表面的正电荷数量从而使吸附量发生变化.4种恒电荷土壤对NO-3的吸附量通常很小,其中在Ca(NO3)2介质中较在其他介质中稍大,最大吸附量仅为1.5mmolkg-1左右,约为可变电荷土壤的1/10,且在浓度较低时常观察到负吸附.     

恒电荷土壤和可变电荷土壤动电性质的研究 Ⅱ.阴离子吸附和pH的影响

本工作研究了阴离子吸附和ＰＨ对恒电荷土壤（黄棕壤和黑土）和可变电荷土壤（砖红壤）动电性质的影响。结果表明,砖红壤吸附不同阴离子后的ζ电位随ＰＨ升高由正电位移至负电位,在ζ电位－ＰＨ曲线上均有一个等电点（ＩＥＰ）在ＰＨ３．５～８之间,相同ＰＨ升高由正电红壤的ζ电位随吸附阴离子的负移顺序是ＨＰＯ４＾２－〉Ｆ＾－〉ＳＯ４＾２－〉Ｃｌ＾－〉ＮＯ３＾－。作为恒电荷土壤的黄棕壤和黑土,在不同电解发质溶液中的ε     

阴离子对可变电荷土壤吸附铜离子的影响机理

根据NO-3、Cl-和SO24-对可变电荷土壤和恒电荷土壤吸附Cu2+的影响的比较,探讨了阴离子对可变电荷土壤吸附Cu2+的影响机理。结果表明,当3种阴离子的浓度相同时,在SO24-体系中铁质砖红壤对Cu2+的吸附率较在NO3-和Cl-体系中大得多,而在浓度相同的3种阴离子体系中,黄棕壤对Cu2+的吸附率相差不大。在离子强度相近的NaCl体系中,砖红壤对Cu2+的吸附率相近。在3种阴离子体系中,随着pH升高,砖红壤对Cu2+的吸附率均增大;但在NO-3体系和Cl-体系中Cu2+的吸附率相近;而在SO24-体系中Cu2+的吸附率最大。随着Na2SO4浓度的增大,铁质砖红壤和砖红壤对Cu2+的吸附率减小。但在0.005 mol L-1和0.05 mol L-1Na2SO4体系中,Cu2+的吸附率大于在不含Na2SO4的体系中者。而在0.5 mol L-1Na2SO4体系中,Cu2+吸附率小于在不含Na2SO4体系中者。在3种浓度的Na2SO4体系中,黄棕壤对Cu2+的吸附率均小于在不含Na2SO4体系中者。总之,阴离子可通过离子强度、专性吸附和形成离子对影响土壤对Cu2+的吸附。在可变电荷土壤中,阴离子对Cu2+吸附的影响机理较在恒电荷土壤中复杂得多。     

pH对针铁矿表面磷酸盐吸附的化学形态的影响

Chemical forms of the phosphate adsorbed on goethite surfaces and characteristics of the coordinate groups which exchange with P on goethite surfaces in solutions with different pll values were investigated.Results showed that the chemical forms of P on goethite surfaces changed from the dominance of monodentate corrdination to that of bidentate one with increasing pH of the solution.By influencing types of phosphate ions in solutions,pH affected the chemical forms of P on goethite surfaces,The amount of OH^- displaced by phosphae on goethite surfaces was the most at pH 7.0,the second at pH 9.0,and the least at pH 4.5.     

离子专性吸附对可变电荷土壤的动电学性质的影响

Studies were carried out by using electrophoretic method on the effects of the specific adsorption of the anions,such as SO4^2-,PO4^3-,and F^- ions,the cations,such as Ca^2 ,Mn^2 ,Zn^2 ,and Cu^2 ,ions,and the anions and cations coexisting,such as Zn^2 and SO4^2= ions,on electrokinetic properties of the red soils as typical variable charge soils in China concerning variation in the specific ion species and concentrations,with an emphasis on the interaction between soil colloid surfaces and the ions in soil solutions.The results showed that the adsorption of specific ions led to a very pronounced decrease in zeta potentials of the soil colloids and a shift of the IEPs to lower values for specific anions,and an obvious increase in zeta potentials of the soil colloids and a shift of the IEPs to higher values for specific cations.Under circumstances of the specific anions and cations coexisting,for instance,Zn^2 and SO4^2- ions,the zeta potentials changed with values higher than the value for SO4^2- alone and lower than that for Zn^2 alone,and the IEP was between that for Zn^2 and that for SO4^2-.The adsorption of Zn^2 and Cu^2 ions resulted in a reversal of the zeta potentials,and appearance of two IEPs for Zn^2 and no IEP for Cu^2 ,exhibiting interesting special effects of these kinds of metal ions.The higher the concentrations of the ions,the greater the change of the electrokinetic properties.     

两种土壤中邻苯二胺对铜离子吸附—解吸平衡影响的研究

采用室内测试方法，研究了低浓度的外源铜离子在两种不同性质土壤中的吸附、解吸过程及其受邻苯二胺的影响。结果发现，外源铜离子在红壤中的吸附随pH的变化明显变化，而在黑土中的吸附则随pH变化改变较小，吸附在红壤中的铜较吸附在黑土中的铜更易于解吸，有机物邻苯二胺对铜在两种土壤中的吸附和解吸过程产生了明显影响。酸性条件下邻苯二胺的存在增加了红壤对铜的吸附量，但同时也增加了铜的解吸百分数。而邻苯二胺基本不改变铜在黑土中的表观吸附量，但显著影响铜的解吸百分数。     

外源硅对不同pH水田土壤铅吸附热力学特征的影响

通过等温吸附试验,研究外源硅对两种不同pH水田土壤铅吸附热力学特征的影响。试验中采用硝酸中和硅酸钠的碱性,以硝酸钠补齐各处理间钠离子和硝酸根离子的差异,消除了因加入硅酸盐改变体系pH及伴随离子对土壤吸附铅可能产生的影响。结果表明：在本试验中,Freundlich方程能较好地描述3种温度下两种土壤对铅的吸附特征;加硅促进了酸性土壤对铅的吸附,抑制了碱性土壤对铅的吸附;根据热力学函数关系计算的△G〈0、△H〉0、△S〉0,说明两土壤对铅的吸附是吸热、熵增的物理过程为主;加硅后,酸性土壤△G变小、△H变大、△S变大,碱性土壤△G变大、△H变小、△S变小,说明加硅使酸性土壤吸附铅的自发性提高、碱性土壤吸附铅的自发性降低。     

土壤磷酸盐的吸收对Cu2+二次吸附动力学的影响

The effects of sorbed phosphate on the kinetics of Cu^2 secondary adsorption on three major types of soils in southern and Central China were studied using the batch method and flow (or miscible displacement) techniques.Both of the methods showed that diffusions were the ratedetermining steps in the Cu^2 adsorption by the soils.By the flow method,the course of Cu^2 adsorption kinetics consisted of two steps-sn initial rapid process and a later slow process of Cu^2 adsorption;while by the batch method,the 90% of Cu^2 adsorption reaction was found to finish within first 1 minute.The results obtained using the flow method also indicated that for red soil and yellow-brown soil ,Cu^2 adsorptions during the initial reaction periods were restrained when the soils sorbed phosphate,whereas the adsorption reactions were stimulated at the final time,For grey Chao soil,sorbed phosphate retarded the Cu^2 adsorption in the whole reaction period.The results obtained using the batch method and low techniques all implied that the different effects of sorbed phosphate would be attributed to its effects on Cu^2 ion diffusion in soil solution.     

Effect of the storage conditions of soil samples on carbon and nitrogen extractability

Concentrations of carbon and nitrogen extractable by 0.05 M K₂SO₄ (C_ext and N_ext, respectively) in 14 soils of different ecosystems vary from 16 to 205 and from 4 to 53 mg/kg, respectively. The portion of C_ext in soil organic matter is 0.06 to 0.38% of total carbon, and the portion of N_ext is 0.12–1.05% of total nitrogen. The storage of samples and their preparation to analysis differently affect the extractability of elements. The concentration of C_ext is less variable than the concentration of N_ext. An increase in C extractability (by 1.4–6.7 times) is a common feature of all soils under drying; at the following incubation of dried soils, the extractability of C decreases by 28–56%. The extractability of N increases not only under drying (by 1.5–7.1 times) and the following incubation of samples (by 25–60% to 2–3 times), but also under freezing of most soils and at the incubation of fresh and defrozen samples. A close direct correlation is observed between the initial water content of soil and the relative increase in C extractability under drying and N extractability under freezing and drying.     

Effect of microorganisms on extractability of Cd from soil with NaOH and DTPA

Because Cd is extremely toxic, an understanding of the factors that allow or prevent Cd entrance into the food chain is important. The fate of Cd in soil is strongly influenced by microbial activity. Thus, an attempt was made to develop a method for studying the effect of microorganisms on Cd sorption to soil and availability to plants. It was found that the amount of Cd extracted from soil to soil suspensions with 0.1 m NaOH is related to microbial proliferation. In addition, an increase of Cd in NaOH extracts occurred concurrently with a decrease of Cd in DTPA extracts. Our observations suggest that the binding of Cd to microorganisms or their products can immobilize Cd and consequently affect its bioavailability.     

添加秸秆碳源对土壤微生物生物量和原生动物丰富度的影响

为了研究引入秸秆碳源对根结线虫(Meloidogyne spp.)病害严重土壤中微生物生物量和原生动物的影响, 以番茄为供试作物, 设置4个梯度的小麦秸秆添加量[CK(0 g·kg^-1), 1N(2.08 g·kg^-1)、2N(4.16 g·kg^-1)和4N(8.32 g·kg^-1)], 研究不同种植时间(6个月和4个月)下土壤微生物生物量碳、氮和原生动物丰度的变化。研究结果表明: 添加秸秆对微生物生物量碳、氮和原生动物丰富度有明显促进作用, 添加的秸秆量越多, 这种促进作用越明显。不同秸秆添加量处理中, 微生物生物量碳、氮和原生动物丰度为: 4N>2N>1N>CK。秸秆对原生动物的群落结构也有显著影响, 在各处理中, 鞭毛虫和肉足虫占有绝大比例, 分别占总丰度的29.44%和66.19%, 纤毛虫仅占4.37%。在相同添加秸秆量条件下, 土壤原生动物丰度随种植时间的延长而提高, 而微生物生物量碳、氮量随种植时间的延长而降低。而在种植时间相同条件下, 随着秸秆量的增加土壤微生物生物量碳、氮量和微生物生物量碳氮比和原生动物总丰度相应增加。     

Catechol and chlorocatechols in soil: Degradation and extractability

Catechol and chlorocatechols occur as intermediary metabolites during the degradation of naturally-occurring and synthetic aromatic compounds. Their degradation in soil was assessed under laboratory conditions using ¹⁴C-tracing techniques. Degradation of all compounds to CO₂ was rapid during the first 2 weeks (5–10% week^?1, but gradually decreased to below 1% week^?1 after 3 months. After 6 months. 44% of 4,5-dichlorocatechol, 38% of 4-chloro- and tetrachlorocatechols, and 30% of catechol were degraded to CO₂. In comparison, chlorophenols were degraded at similar rates, and chloroanilines were degraded more slowly. A mixed extradant of citric acid-ascorbic acid-acetone (1:1:2) was found to be most effective in extracting the catcchols from variously-treated soil samples. Recovery of added ¹⁴C from freshly fortified soils ranged from 74% for catechol to 98%, for tetrachlorocatechol. After equilibration of ¹⁴C-chemical with soil for 5–20 days, the extractability decreased to 38% for catechol, but remained over 86% for tetrachlorocatechol. Sterilization of soil before ¹⁴C addition had little effect on ¹⁴C extractability. After incubation of treated soil for 5 months, only 20–35% of residual ¹⁴C could be extracted. More than half of the nonextractable ¹⁴C-residues from incubated soil could be further removed by Na-pyrophosphate extraction.     

Effect of lead on soil respiration and dehydrogenase activity

The effect of added Pb on the respiration and dehydrogenase activity of two sandy soils, a clay soil and a peat soil, (all with different physico-chemical properties), was studied.A concentration of 375 μg Pb· g^? inhibited the respiration of the sandy soil by ca. 15%, 1500 μg Pb· g^?ca. 50%. In the clay soil 1500 μg Pb· g^? caused a 15% reduction in respiration. The inhibition of respiration in the sandy soil was still ca. 30% 40 months after the addition of Pb. Respiration of the peat soil was not affected by even 7500 μg Pb· g^?.Dehydrogenase activity was affected by Pb in a similar way to soil respiration. In the sandy soil a considerable reduction occurred, while in the clay and peat soils dehydrogenase activity was not reduced.It was concluded, that a relationship exists between the inhibitory effects of Pb and the buffering capacity of the soil as expressed by its cation-exchange capacity. Because of these different effects of the same Pb concentration on the various soil types, no single value for the permitted concentration of lead pollution in soil could be established.     

Availability and extractability of soil manganese in a liming experiment

Abstract

The availability of soil Mn to corn in relation to extractability of soil Mn by EDTA, Mg(NO₃)₂, CH₃COONH₄, hydroquinone, H₃PO₄, and NH₄H₂PO₄ as affected by liming was evaluated under field conditions on a single soil type. EDTA, Mg(NO₃)₂ and CH₃COONH₄‐extractable Mn were related inversely to available Mn. No useful relationships were found between hydroquinone, H₃PO₄, and NH₄H₂PO₄‐extractable soil Mn and Mn uptake by sweet corn.     

秸秆还田配施腐熟剂对低产黄泥田的改良作用

【目的】低产黄泥田是一种发育程度低的水稻土,土壤贫瘠,作物产量低。本文研究探讨了小麦、 水稻、 油菜秸秆还田及配施秸秆腐熟剂后秸秆还田对低产黄泥田的土壤改良效果。【方法】在荆门市双季稻区设置了单施化肥(对照),化肥配施小麦、 水稻、 油菜秸秆,化肥配施小麦、 水稻、 油菜秸秆同时添加秸秆腐熟剂等七个处理的田间试验。取样分析了这些处理对双季稻产量、 土壤理化性质、 土壤团聚体组成、 土壤腐殖质组成及结合形态的影响。【结果】1)在早、 晚稻上秸秆还田配施秸秆腐熟剂增加了稻谷的产量,比单施化肥最多增产1423.2 kg/hm2,增幅为23.5%; 添加秸秆腐熟剂也能够增加稻谷的产量,比单独秸秆还田最多增产653.8 kg/hm2,增幅为9.6%。与对照比较,油菜秸秆+腐熟剂处理晚稻显著增产。2)土壤有机质、 全氮、 碱解氮、 有效磷、 速效钾含量、 阳离子交换量秸杆+腐熟剂处理高于对应的秸秆还田处理,而土壤容重则下降。3)与对照比较,秸秆处理5 mm土壤风干团聚体含量增加3.78%~8.62%,0.25 mm土壤风干团聚体含量也都增加,0.25 mm水稳定性团聚体含量下降。秸秆还田有利于＞0.25 mm水稳定性大团聚体总量的增加,减少了土壤团聚体破坏率。4)与对照比较,秸秆处理的土壤水溶性物质、 土壤胡敏酸、 富里酸、 可提取腐殖物质总量、 胡敏素含量增加。添加腐熟剂后,胡敏酸与富里酸比值低于相对应的秸秆还田处理; 土壤松结合态腐殖质、 稳结合态腐殖质、 紧结合态腐殖质含量及结合态腐殖质总含量都有所增加。结合态腐殖质中松结合态腐殖质含量最高,所有的处理都在60%以上。【结论】秸秆还田配施秸秆腐熟剂不仅能够增加早稻和晚稻的稻谷产量,还提高了土壤有机质、 全氮、 碱解氮、 有效磷、 速效钾含量及阳离子交换量,降低了土壤容重。秸秆还田主要提高了＞0.25 mm风干团聚体、 水稳性大团聚体含量,减少了土壤团聚体破坏率。秸秆还田处理显著提高了土壤松结合态腐殖质含量和结合态腐殖质总含量。秸秆还田配施秸秆腐熟剂可以提高作物产量、 提高土壤肥力、 改善土壤结构、 增加土壤腐殖质含量与活性,能够改良低产黄泥田。化肥+油菜秸秆+秸杆腐熟剂处理是一种良好的低产黄泥田改良措施。     

铅对两个红壤中酶活性的影响

Enzyme activities have the potential to indicate biological functioning of soils. In this study, soil urease, dehydrogenase, acid phosphatase and invertase activities and fluorescein diacetate（FDA） hydrolysis were measured in two red soils spiked with Pb^2＋ ranging from 0 to 2 400 mg kg^-1 to relate the enzyme activity values to both plant growth and the levels of available and total Pb^2＋ concentrations in soils, and to examine the potential use of soil enzymes to assess the degrees of Pb contamination. Soil samples were taken for enzyme activities assaying during 3 month’s incubation and then after planting of celery（Apium graveolens L.） and Chinese cabbage（Brassica chinensis L.）. Enzyme activities in the red soil derived from arenaceous rock（RAR） were generally lower than those in the red soil developed on Quaternary red earths（REQ）. At high Pb^2＋ loadings, in both incubation and greenhouse studies, urease activity and FDA hydrolysis were significantly inhibited. But there were no significant relationships between soil dehydrogenase, acid phosphatase or invertase activity and soil Pb^2＋ loadings in both RAR and REQ soils. The growth of celery and Chinese cabbage increased soil urease activity and FDA hydrolysis, but had minimal effect on dehydrogenase and invertase activities. There were positive correlations between celery biomass and soil urease activity and FDA hydrolysis. These results demonstrate that urease activity and FDA hydrolysis are more sensitive to Pb^2＋ than acid phosphatase, dehydrogenase and invertase activities in the RAR and REQ soils.     

阴离子对应用于红壤中的微生物量的镉毒害的影响

A laboratory incubation experiment was conducted to elucidat the effects of associated anions on toxicity of cadmium applied to microbial biomass in the red soil. Cadmium was applied at six different levels,i.e.,O(background),5,15,30,60 and 100μg g^-1 soil in the form of either cadmium acetate or cadmium chloride. Application of cadmium as cadmium acetate markedly reduced the soil microbial biomass carbon compared to cadmium applied as cadmium chlorde at all the tested levels.Similarly,organic carbon to biomass carbon ration in the soil was markedly increased by increasing the level of the cadmium in the soil as cadmium acetate,while the change wa much smaller in the case of cadmium chloride at the same cadmium levels.The results suggested that due consideration should be given to the source of cadmium while deciding the cadmium levles in experiments.     

Effect of attendant anions on the adsorption of zinc, copper, and lead by chernozem

The adsorption of Cu, Zn, and Pb from acetate solutions is accompanied by higher values of the affinity constants compared to the adsorption of the same cations from nitrate solutions. The observed differences are due to the formation of stable charged complexes of acetate ions with heavy metal cations, whose binding strength with the surface of soil particles is higher than that of free ions, and also due to the possible precipitation of poorly soluble metal compounds in a calcareous ordinary chernozem.