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1.
KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of cations and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and releasing aluminum of four kinds of cations was in the decreasing order Ca2+ >K+ >NH4+ >Na+. The dissolution of aluminum increased with the cation concentration. The adsorption affinity of various soils for aluminum was different. The aluminum in the soil with a stronger adsorption affinity was difficult to be exchanged and released by cations. The Al-F complexes were main species of inorganic aluminum at a low concentration of cations, while Al3+ became major species of inorganic aluminum at a high concentration of cations. The results on the effect of anions indicated that the concentrations of total aluminum, three kinds of inorganic aluminum (Al3+, Al-F and Al-OH complexes) and organic aluminum complexes (Al-OM) when SO42- was added into soil suspension were lower than those when Cl- was added. The dissolution of aluminum from soils and the distribution of aluminum forms in solution were affected by the adsorption of F- on the soil. For soils with strong affinity for F-, the concentrations of the three inorganic aluminum species in soil solution after addition of F- were lower than those after addition of Cl-; but for soils with weak affinity for F-, the concentrations of Al3+ and Al-OM were lower and the concentrations of Al-F complexes and total inorganic aluminum after addition of F- were higher than those after addition of Cl-. The increase of F- concentration in soil solution accelerated the dissolution of aluminum from soils. 相似文献
2.
用电导频散法研究Cl-、SO42-和H2PO4-阴离子与土壤的相互作用 总被引：2，自引：0，他引：2
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-、SO42-和H2PO4-离子与4种土壤的相对亲合力(REC1.5/RECtp-1)顺序为Cl- < SO42- < H2PO4-,在不同土壤之间的顺序则随酸溶液而异. 相似文献
3.
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 (ΔK0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 相似文献
4.
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 总被引：1，自引：0，他引：1
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-, SO42-, 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 SO42- ≤ H2PO42- < 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). 相似文献
5.
第四纪红色粘土发育的红壤中营养元素的淋失 总被引：13，自引：2，他引：11
A red soil derived from Quaternary red clay was employed to study nutrient leaching with soil columns repacked in laboratory. The objective was to identify the effects of fertilization practices on leaching patterns and magnitudes of Ca2+, Mg2+, K+, NH4+, and NO3-. The treatments were CK (as a control), CaCO3, CaSO4, MgCO3, Ca(H2PO4)2, urea, KCl, and multiple (a mixture of the above-mentioned fertilizers). The fertilizers were added to the bare surface of the soil columns, and then the columns were leached with 120 mL deionized water daily through peristaltic pumps over a period of 92 days. Leaching processes of NH4+, and NO3- were only measured in CK, urea, and multiple treatments which were directly related to N leaching. Results showed that sole application of CaSO4, and Ca(H2PO4)2 scarcely had any effect on the leaching losses of Ca2+, Mg2+, and K+; the application of MgCO3 stimulated the leaching of Mg2+; the application of CaCO3 promoted the leaching of Ca2+, Mg2+ and K+; urea treatment also promoted the leaching of K+ and NH4+, and NO3- leaching mainly occurred at late stage of leaching process in particular; under KCl treatment, leaching of Ca2+, Mg2+, and K+ was promoted to a large extent; under multiple treatment, leaching of Ca2+, Mg2+, K+, NH4+, and NO3- was all increased and NO3- was mainly leached at the end of leaching process and still had a trend of increase. 相似文献
6.
在甘肃省河西内陆灌区的制种玉米田,采用田间试验方法,研究了保水型专用肥对土壤物理性质和蓄水量的影响及制种玉米田最佳施肥量。结果表明,影响玉米产量的因素由大到小依次为:CO(NH2)2>(NH4)2HPO4>糠醛渣>保水剂>ZnSO4·7H2O;因素间最佳组合为:CO(NH2)2600kg/hm2,(NH4)2HPO4350kg/hm2,ZnSO4·7H2O 30kg/hm2,保水剂19.98kg/hm2,糠醛渣15 000kg/hm2。保水型专用肥施肥量与玉米制种田容重呈负相关关系,与孔隙度、蓄水量、玉米植物学性质和经济性状呈正相关关系。随着保水型专用肥施用量梯度的增加,玉米穗粒数、穗粒重、百粒重、产量在增加,但边际产量、边际利润表现为递减,保水型专用肥施用量在10.00t/hm2的基础上再增加2.50t/hm2,收益出现负值。经回归统计分析,保水型专用肥施用量与玉米产量可用一元二次方程拟合,经济效益最佳施肥量为9.99t/hm2,玉米的理论产量为6 715.33kg/hm2。 相似文献
7.
Fifteen upland soils collected from the major arable areas in North China were used to assess the availability of soil sulfur (S) to plants in a pot experiment. Soils were extracted with various reagents and the extractable S was determined using turbidimetric method or inductively coupled plasma atomic emission spectrometry (ICP-AES), respectively. In addition, mineralizable organic S, organic S, N/S ratio, sulfur availability index (SAI) and available sulfur correction value (ASC) in soils were also determined. The S amount extracted by 1.5 g L-1 CaCl2 was nearly equivalent to that by 0.25 mol L-1 KCl (40 ℃), and both of them were slightly smaller than that by 0.01 mol L-1 Ca(H2PO4)2 solution, as measured by turbidimetric method or ICP-AES. The extractable S measured by turbidimetric method was consistently smaller than that by ICP-AES. All methods tested except that for organic S and N/S ratio produced satisfactory results in the regression analyses of the relationships between the amounts of S extracted and plant dry matter weight and S uptake in the pot experiment. In general, 0.01 mol L-1 Ca(H2PO4)2-extracted S determined by ICP-AES or turbidimetric method and 0.25 mol L-1 KCl (40 ℃)-extracted S determined by ICP-AES appeared to be the best indicators for evaluation of soil available S. 相似文献
8.
中国陕西省施有机肥黄土NH4+固定的热力学性质 总被引：3，自引：0，他引：3
Some thermodynamic properties of NH4+ fixation by loess soil in plowing and clay layers are discussed. The results indicate that the four ion adsorption equations commonly used can describe the properties of NH4+ fixation in these soils under constant temperature. Among the four adsorption equations, the single-surface Langmuir equation is the best. When the concentration of NH4Cl solution is 10-1 mol below, the Freundlich equation can be used. The changes of apparent standard free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) illustrate that NH4+ fixation in soil is an endothermic adsorption and spontaneous reaction, and the process can be enhanced by a higher temperature and clay content in soil. The "proper value of NH4+ fixation by soil (K1 × qm) increased with increasing clay content and temperature. The heat of NH4+ fixation in soil (Qm) confirms the conclusions made in this paper. 相似文献
9.
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. 相似文献
10.
Effects of NH4+ concentration, solution/soil ratio and temperature on NH4+ adsorption were studied in a Eum-Orthic Anthrosol. The slopes of the soil NH4+ adsorption isotherms and the fitted n, the coefficient for the adsorption intensity, and k, the coefficient related to adsorption capacity, of the Freundlich equation increased with increasing solution/soil ratio (SSR) and with decreasing temperature (T). For the range of experimental conditions, the value of ∂q/∂c, the rate of change of the amount of NH4+ adsorbed in the soil solid phase (q) with respect to the equilibrium concentration of NH4+ in soil solution (c), was 0.840, indicating that q increased with increasing c. From 2 to 45 ℃, ∂q/∂SSR, the rate of change of q with respect to SSR, decreased from 2.598 to 1.996, showing that q increased with increasing SSR, while its increasing rate decreased with temperature. From SSR 1:1 to 20:1, ∂q/∂T, the rate of change of q with respect to T, decreased from -0.095 to -0.361, indicating that q decreased with increasing temperature, and at the same time the negative effect of temperature became larger as SSR increased. Thus under the experimental conditions the order of importance in determining the amount of NH4+ adsorbed in the soil solid phase was ∂q/∂SSR > ∂q/∂c > |∂q/∂T|, indicating that the greatest effect on the amount of NH4+ adsorbed was with the solution/soil ratio; the equilibrium concentration of NH4+ had a lesser effect; and temperature had the least effect. 相似文献
11.
影响土壤镉吸持和解吸的因子 总被引：10，自引：0，他引：10
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-、SO42-、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。 相似文献
12.
The effect of background anion on cation exchange reactions, such as Na-Ca and Na-Cu exchange reactions, on montmorillonites has been studied, but the results are not always clear and discrepancies exist in the literature. In this study, the exchange of zinc (Zn2+) for sodium (Na+) on Wyoming montmorillonite was investigated at 298°K using Cl-, ClO4-, NO3-, OAc-, and SO42- solution media at a constant total metal charge concentration of 0.0200 molc L-1. Results indicated that the clay CEC values were essential similar for Cl-, ClO4-, NO3- and SO42- solution media with an average CEC of 0.856 ± 0.008 molc kg-1; in an OAc+ solution the clay CEC was much higher than that in other anion media. The specific adsorption of Zn (SAZn), as defined by the extraction of Zn using 0.05mol L-1 Na2-EDTA, was different in the various background solutions. The highest value for SAZn was 0.359 ± 0.0350molc kg-1, which occurred in OAc-solution. There was essentially no difference in the total apparent adsorbed metals (the sum of adsorbed equivalents of Na and Zn per kilogram of clay, Q) among the various background solutions. The average Q for all anion media was 0.807 ± 0.011 molc kg-1 and was independent of exchanger composition. Experimental results indicated that there were no significant monovalent cation complexes such as ZnCl+ or ZnNO3+ that were adsorbed by montmorillonite. The Na-Zn exchange isotherms indicated that there was an adsorption preference for Zn over Na on Wyoming montmorillonite. 相似文献
13.
上海郊区园艺土壤氮素的生物形成动态变化 总被引：3，自引：0，他引：3
Dissolved organic nitrogen (DON) represents a significant pool of soluble nitrogen (N) in soil ecosystems. Soil samples under three different horticultural management practices were collected from the Xiaxiyang Organic Vegetable and Fruit Farm, Shanghai, China, to investigate the dynamics of N speciation during 2 months of aerobic incubation, to compare the effects of different soils on the mineralization of 14C-labeled amino acids and peptides, and to determine which of the pathways in the decomposition and subsequent ammonification and nitrification of organic N represented a significant blockage in soil N supply. The dynamics of N speciation was found to be significantly affected by mineralization and immobilization. DON, total free amino acids, and NH4+-N were maintained at very low levels and did not accumulate, whereas NO3--N gradually accumulated in these soils. The conversion of insoluble organic N to low-molecular-weight (LMW) DON represented a main constraint to N supply, while conversions of LMW DON to NH4+-N and NH4+-N to NO3--N did not. Free amino acids and peptides were rapidly mineralized in the soils by the microbial community and consequently did not accumulate in soil. Turnover rates of the additional amino acids and peptides were soil-dependent and generally followed the order of organic soil > transitional soil > conventional soil. The turnover of high-molecular-weight DON was very slow and represented the major DON loss. Further studies are needed to investigate the pathways and bottlenecks of organic N degradation. 相似文献
14.
塔里木盆地西南缘典型灌区土壤盐渍化特征分析——以塔吉克阿巴提镇为例 总被引：1，自引：0，他引：1
在野外GPS定点定位调查、土壤样品分析的基础上,借助Excel和ArcGIS9.3等软件,对新疆自治区喀什市岳普湖县塔吉克阿巴提镇0-30cm土层的盐离子特征、灌区土壤盐渍化现状及空间分布特征进行了分析。结果表明,0-30cm土层土壤中的离子以Cl-,SO42-,Na+,Ca2+为主Na+与Cl-呈极显著正相关关系,相关系数为0.98,HCO3-与其它6种离子(Na+,Ca2+,Mg2+,K+,Cl-,SO42-)呈负相关关系受灌排系统影响较大的农田0-30cm土壤中Cl-/SO42-比值远小于不受灌排系统影响的荒地农田和荒地0-30cm土壤中的Cl-/SO42-比值与总盐呈正相关关系,相关系数依次为0.68和0.32。现阶段对塔吉克阿巴提镇灌区农业危害最严重的是氯化物-硫酸盐盐渍化土,硫酸盐盐渍化土表现为盐渍化土地向非盐渍化土地转变的过渡类型非盐渍化农田及轻度盐渍化农田主要分布在开垦较早,灌排系统畅通的区域,灌排系统不畅通的区域仍然处于脱盐缓慢或持续积盐的状态。 相似文献
15.
Hydroxyl release of red soil and latosol surfaces was quantitatively measured using a self-made constant pH automated titration instrument, to study the changes of hydroxyl release with different added selenite amounts and pH levels, and to study the effects of electrolytes on hydroxyl release. Hydroxyl release increased with the selenite concentration, with a rapid increase at a low selenite concentration while slowing down at a high concentration. The pH where maximum of hydroxyl release appeared was not constant, shifting to a lower valus with increasing selenite concentration. Hydroxyl release decreased with increasing electrolyte concentration, and the decrease was very rapid at a low electrolyte concentration but slow at a high electrolyte concentration. For NaClO4, NaCl and Na2SO4 hydroxyl release was in the order of NaClO4 > NaCl 》 Na2SO4, and the difference was very significant. But for NaCl, KCl and CaCl2, the order of hydroxyl release was NaCl > KCl > CaCl2, and the difference was smaller. The amount of hydroxyl release from Xuwen latosol was greater than that from Jinxian red soil. Hydroxyl release existed in a wider range of pH with Xuwen latosol than with Jinxian red soil, due to their difference in soil properties. However, both soils had similar curves of hydroxyl release, indicating the common characteristics of variable charge soils. 相似文献
16.
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。 相似文献
17.
小麦根际Cr(Ⅵ)的还原 总被引：2，自引：0，他引：2
Reduction of Cr(Ⅵ) to Cr(Ⅲ) was studied in a fresh wheat rhizosphere soil (kuroboku, high humic Andosol) pretreated with a basal fertilizer consisting of (NH4)2SO4, P2O5 and KH2PO4 and with K2Cr2O7 by using a rhizobox system. The rhizosphere exerted a positive effect on Cr(Ⅵ) reduction. Part of the reason was the decrease of pH in the rhizosphere due to application of (NH4)2SO4, implying that application of physiologically acid fertilizers would reduce Cr(Ⅵ) toxicity to plants. 相似文献
18.
The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variable charge soils, with different surface charge properties were studied. Under the conditions of the same pH and ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of Cl- > NO3- > ClO4-, indicating the difference of the nature among these three anions. For Ferralsol in the same concentration of chloride and perchloride solutions, the two sulfate adsorption-pH curves could intersect at certain pH value. When pH was higher than the intersecting point, more sulfate was adsorbed in the perchloride solution, while when it was lower than the intersecting point, more sulfate was adsorbed in the chloride solution. In different concentrations of electrolyte solution, the curves of the amount of oxy-acid anion adsorbed, which changed with pH, could intersect at a certain pH, which is termed point of zero salt effect (PZSE) on adsorption. The nature of electrolyte anions influenced obviously the appearance of PZSE for sulfate adsorption. For ferralsol the curves of adsorption converged to about pH 7 in NaCl solution seemed to intersect in NaNO3 solution and to have a typical PZSE for sulfate adsorption in NaClO4 solution. For Acrisol the three curves of adsorption were nearly parallel in NaCl and NaNO3 solutions and converged to pH 6.5 in NaClO4 solution. 相似文献
19.
Interactions of three heavy metal ions, Cu2+, Cd2+, and Pb2+, and, for comparison, Na+ with electrodialytic clay fractions (less than 2 μm in diameter) of four paddy soils as well as a yellow-brown soil as a control soil were evaluated based on measurements of the Wien effect in dilute suspensions with a clay concentration of 10 g kg?1 in four nitrate solutions of 2 × 10?4/z mol L?1, where z is the cation valence, and a nitric acid solution of 3 × 10?5 mol L?1. Field strengths ranging from 15 to 230 kV cm?1 were applied for measuring the electrical conductivities (ECs) of the suspensions. The mean free binding energies between the various cations and all of the soils determined from exchange equilibrium increased in the order: Na+ < Cd2+ < Cu2+ < Pb2+. In general, the ECs of the suspensions in the sodium nitrate solution were smaller than those of the suspensions in the heavy metal solutions because of the lower electrophoretic mobility of sodium compared to the divalent cations. In terms of relative electrical conductivity-field strength relationships, relative electrical conductivity (REC) of suspensions containing various cations at field strengths larger than about 50 kV cm?1 were in the descending order: Na+ > Cu2+ > Cd2+ > Pb2+ for all tested soils. A characteristic parameter of the REC-field strength curves, ΔREC200, REC at a field strength of 200 kV cm?1 minus that at the local minimum of the concave segment of the REC-field strength curves, characterized the strength of adsorption of the cations stripped off by the applied strong electrical field, and for all soils the values of ΔREC200 were generally in the order: Na+ < Cu2+ ≤ Cd2+ ≤ Pb2+. 相似文献