Exploitation of potassium by various crop species from primary minerals in soils rich in micas     

K. Mengel  Rahmatullah 《Biology and Fertility of Soils》1994,17(1):75-79

We investigated the question of whether exchangeable K⁺ is a reliable factor for K⁺ availability to plants on representative arable soils (Aridisols) rich in K⁺-bearing minerals. Five soils with different textures were collected from different locations in Pakistan and used for pot experiments. The soils were separated into sand, silt, and clay fractions and quartz sand was added to each fraction to bring it to 1 kg per kg whole soil, i.e., for each fraction the quartz sand replaced the weight of the two excluded fractions. On these soil fraction-quartz mixtures wheat, elephant grass, maize, and barley were cultivated in a rotational sequence. Growth on the sand mixture was very poor and except for the elephant grass all species showed severe K⁺-deficiency symptoms. Growth on the mixture with silt and clay fractions was much better than on the sand fraction; there was no major difference in growth and K⁺ supply to plants whether grown on silt or clay, although the clay fraction was rich and the silt fraction poor in exchangeable K⁺. On both these fractions the plant-available K⁺ supply was suboptimal and the plants showed deficiency symptoms except for the elephant grass. This plant species had a relatively low growth rate but it grew similarly on sand, silt, and clay and did not show any K⁺ deficiency symptoms, with the K⁺ concentration in the plant tops indicating a sufficient K⁺ supply regardless of which soil fraction the plants were grown in. The reason for this finding is not yet understood and needs further investigation. It is concluded that on soils rich in mica, exchangeable K⁺ alone is a poor indicator of K⁺ availability to plants and that mica concentrations in the silt and clay fraction are of greater importance in supplying crops with K⁺ than exchangeable K⁺.  相似文献   

Plant Availability Index by Potassium Exchange Isotherms in Selected Rice Soils of Lesser Himalayas     

《Communications in Soil Science and Plant Analysis》2012,43(17):2073-2084

Potassium (K) exchange isotherms (quantity–intensity technique, Q/I) and K values derived from the Q/I relationship provide information about soil K availability. This investigation was conducted to study Q/I parameters of K, available K extracted by 1 N ammonium acetate (NH₄AOc) (exchangeable K plus solution K), K saturation percentage (K index, %), and the properties of 10 different agricultural soils. In addition, the relationship of mustard plant yield response to the K requirement test based on K exchange isotherms was investigated. The Q/I parameters included readily exchangeable K (ΔK₀), specific K sites (K_X), linear potential buffering capacity (PBC^K), and energy of exchange of K (E_K). The results of x-ray diffraction analysis of the oriented clay fractions indicated that some mixed clay minerals, illite clay minerals, along with chlorite/hydroxy interlayered vermiculite and kaolinite were present in the soils. The soil solution K activity ratio at equilibrium (AR₀) ranged from 8.0 × 10^?4 to 3.1 × 10^?3 (mol L^?1)^0.5. The readily exchangeable K (ΔK₀) was between 0.105 to 0.325 cmol_ckg^?1 soil, which represented an average of 88% of the exchangeable K (K_ex). The soils showed high capacities to maintain the potential of K against depletion, as they represented high linear potential buffering capacities (PBC^K) [13.8 to 50.1 cmol_c kg^?1/(mol L^?1)^0.5. The E_K values for the soils ranged from ?3420 to ?4220 calories M^?1. The percentage of K saturation (K index) ranged from 0.7% to 2.2%. Analysis of variance of the dry matter (DM), K concentrations, and K uptake of mustard plants indicated that there were no significant differences among the adjusted levels of K as determined by the exchange-isotherm curve.  相似文献   

紫色土K⁺吸附解吸动力学研究   总被引：7，自引：0，他引：7       下载免费PDF全文

熊明彪  田应兵  宋光煜  石孝均  毛炳衡 《土壤学报》2004,41(3):354-361

从国家紫色土肥力与肥料效益监测基地定位试验上 ,在第 10年水稻收获后从 0～ 30cm土层采取土壤样品 ,研究土壤K 吸附、解吸动力学过程。结果表明 ,不同施肥处理土壤K 吸附、解吸反应分别在2 4～ 32min和 4 6～ 6 4min达到平衡 ,吸附、解吸平衡量分别为 14 1～ 19 2cmolkg-1和 11 6～ 17 5cmolkg-1。相关分析说明 ,土壤阳离子交换量 (CEC)及粘粒含量是影响吸附平衡时间、吸附平衡量的重要因素 ;CEC、交换钾量是影响解吸平衡时间、解吸平衡量的重要因素。由此可见 ,长期不同施肥对土壤CEC、粘粒及交换钾量产生影响 ,从而影响了紫色土K 吸附、解吸平衡时间及吸附、解吸平衡量。平衡前钾离子的吸附、解吸速度及吸附、解吸率与反应时间lnt间存在良好的线性关系。其中反应速度直线和解吸率直线的斜率、初始反应速度及初始吸附率均与CEC、粘粒含量密切相关。Elovich方程和一级扩散方程分别为描述紫色土K 吸附、解吸反应的最优与最差模型 ,指数方程和抛物线扩散方程拟合性介于Elovich方程和一级扩散方程之间。由此可见 ,紫色土K 吸附、解吸过程不是一个单纯的过程 ,而是一个包括土体膨胀、吸附位活化、表面扩散等诸多因素的复杂过程。  相似文献   

Influence of Aluminum Hydroxide on Potassium Release from Two Colombian Soils     

《Communications in Soil Science and Plant Analysis》2012,43(19-20):2783-2792

Abstract

The effect of sesquioxides on the mechanisms of chemical reactions that govern the transformation between exchangeable potassium (Kex) and non‐exchangeable K (Knex) was studied on acid tropical soils from Colombia: Caribia with predominantly 2∶1 clay minerals and High Terrace with predominantly 1∶1 clay minerals and sesquioxides. Illite and vermiculite are the main clay minerals in Caribia followed by kaolinite, gibbsite, and plagioclase, and kaolinite is the major clay mineral in High Terrace followed by hydroxyl‐Al interlayered vermiculite, quartz, and pyrophyllite. The soils have 1.8 and 0.5% of K₂O, respectively. They were used either untreated or prepared by adding AlCl₃ and NaOH, which produced aluminum hydroxide. The soils were percolated continuously with 10 mM NH₄OAc at pH 7.0 and 10 mM CaCl₂ at pH 5.8 for 120 h at 6 mL h^?1 to examine the release of Kex and Knex. In the untreated soils, NH₄ ⁺ and Ca²⁺ released the same amounts of Kex from Caribia, whereas NH₄ ⁺ released about twice as much Kex as Ca²⁺ from High Terrace. This study proposes that the small ionic size of NH₄ ⁺ (0.54 nm) enables it to enter more easily into the K sites at the broken edges of the kaolinite where Ca²⁺ (0.96 nm) cannot have access. As expected for a soil dominated by 2∶1 clay minerals, Ca²⁺ caused Knex to be released from Caribia with no release by NH₄ ⁺. No Knex was released by either ion from High Terrace. After treatment with aluminum hydroxide, K release from the exchangeable fraction was reduced in Caribia due to the blocking of the exchange sites but release of Knex was not affected. The treatment increased the amount of Kex released from the High Terrace soil and the release of Knex remained negligible although with Ca²⁺ the distinction between Kex and Knex was unclear. The increase in Kex was attributed to the initially acidic conditions produced by adding AlCl₃ which may have dissolved interlayered aluminum hydroxide from the vermiculite present, thus exposing trapped K as exchangeable K. The subsequent precipitation of aluminum hydroxide when NaOH was added did not interfere with the release of this K, and so was probably formed mostly on the surface of the dominant kaolinite. Measurement of availability of K by standard methods using NH₄ salts could result in overestimates in High Terrace and this may be a more general shortcoming of the methods in kaolinitic soils.  相似文献   

Short‐term potassium release and fixation in some calcareous soils     

Mohsen Jalali  Zahra Kolahchi 《植物养料与土壤学杂志》2007,170(4):530-537

Potassium (K⁺) directly released from primary K‐bearing minerals can contribute to plant nutrition. The objective of this research was to assess short‐term K⁺ release and fixation on a range of intensively cropped calcareous soils. Potassium sorption and desorption properties and the contributions of exchangeable‐K⁺ (EK) and nonexchangeable‐K⁺ (NEK) pools to K⁺ dynamics of the soil‐solution system was measured using a modified quantity‐to‐intensity (Q : I) experiment. Release and fixation of K⁺ were varied among soils. The relation between the change in the amount of NEK during the experiment and the initial constrain was linear, and soil ability for K⁺ release and fixation (β) for all soils varied from 0.041 to 0.183, indicating that 4% to 18% of added K⁺ converted to NEK when fixation occurred. The equilibrium potential buffering capacity (PBC) for K⁺ derived from Q : I experiments had significant correlation (r = 0.75, p < 0.01) with β, indicating that PBC depends not only on exchange properties but also on release and fixation properties. The depleted soils showed higher β value than the other soils, indicating much of the added K⁺ was converted to NEK in case of positive constraint. The range of the amount of EK which was not in exchange equilibrium with Ca (E_min) in the experimental conditions was large and varied from 0.68 to 9.00 mmol kg^–1. On average, E_min amounted to 64% of EK. This fraction of EK may not be available to the plant. The parameters obtained from these short‐term K⁺ release and fixation experiments can be used in plant nutrition.  相似文献   

Verhalten von Dünger-NH4 in Böden unterschiedlicher tonmineralischer Zusammensetzung im Inkubationsversuch     

Peng-Cheng Guo  J. Bohring  H. W. Scherer 《植物养料与土壤学杂志》1983,146(6):752-759

Fate of fertilizer ammonium in soils with different composition of clay minerals in an incubation experiment In an incubation experiment with three different soils (gray brown podsolic soil from loess, alluvial gley, and brown earth, derived from basalt) the specific adsorption (fixation) and release of fertilizer NH₄⁺ was investigated. In one treatment 120 mg NH₄–N/kg soil was added, while the other treatment (control) received no nitrogen. Soils samples were taken every ten days and analyzed for nonexchangeable and exchangeable NH₄⁺ and NO₃^?. The experimental results are showing that the specific adsorption of applied NH₄⁺ was related to the type of clay minerals. While the loess soil, rich in illite, and the alluvial soil, rich in expansible clay minerals, bound about 40% of the added NH₄⁺ specifically, the soil derived from basalt with mainly kaolinite bound only about 10 %. From the recently “fixed” fertilizer NH₄⁺ about a half was nitrified during the incubation period of about 9 weeks. In the control there was no significant release of specifically bound NH₄⁺. Obviously this NH₄⁺ is located more deeply in the interlayers of the clay minerals and not available to microorganisms.  相似文献   

Einfluß langjähriger Gülledüngung auf den Nährstoffhaushalt des Bodens. 1. Mitteilung: N-Akkumulation und N-Nachlieferungsvermögen     

Heinrich W. Scherer  Wilfried Werner  Andrea Kohl 《植物养料与土壤学杂志》1988,151(1):57-61

Influence of long-term slurry application on soil nutrients. 1. N accumulation and N mineralization potential The influence of longterm slurry applications on the total N content, N fractions and N mobilization potential of the soil was investigated. The following results were obtained:

• – Application of high amounts of slurry over a long period of time resulted in higher total N contents not only in the upper soil layers but also in the layer 60–90 cm.
• – In two sites the higher total N contents are mainly resulting from higher contents of hydrolyzable organic N compounds and in one site of higher contents of non hydrolyzable organic N compounds.
• – The influence of the slurry application on the content of non exchangeable NH₄⁺ is depending on the K saturation of the clay minerals.
• – In incubation experiments N mobilization of the soils supplied with slurry was higher as compared to soils supplied with mineral fertilizer.
• – A highly significant correlation is existing between N mobilization and the content of hydrolyzable organic N compounds and the N_org fraction, determined by means of EUF, respectively.
• – The N_min content of the soils supplied with slurry was higher during the whole growing season.

  相似文献   

Cesium- und Strontiumaustauscheigenschaften von Marschböden     

H. Gebhardt  V. Rosemann 《植物养料与土壤学杂志》1984,147(5):592-603

Cesium and Strontium Exchange Properties of Marsh Soils The cesium and strontium exchange properties of some typical marsh soils of the estuary and lower river Weser region were described. Soil samples were taken according to the existing soil maps 1:25000 of Lower Saxony e.g. a “sea marsh soil”. a “brackish marsh soil”, and a “river marsh soil”. The exchange properties were determined by Cs/Ca and Sr/Ca exchange curves (Q/I relations) as generally used in soil potassium research. In addition to the Q/I relations the following investigations were carried out: - Cs and Sr desorption experiments (one time equilibration with Ca⁺⁺ solutions) - Cs and Sr reexchange experiments (eight times equilibration with water, Ca⁺⁺, Ba⁺⁺, and K⁺ solutions) - the naturally-occuring Cs and Sr contents of the soils including amounts caused by imissions or fallout, respectively - clay mineral composition and swelling of layer silicates due to saturation with Ca⁺⁺, Sr⁺⁺, Cs⁺, and K⁺ ions. Q/I relations as well as desorption and reexchange experiments indicated strong cesium and low strontium fixation by the soils investigated. This was considered the reason for the stronger transfer of Sr from soil to plants as compared with Cs. Furthermore, the reexchange experiment revealed nearly complete reversibility of the Sr sorption reactions by equilibration with the divalent cations Ca⁺⁺ and Ba⁺⁺ and some Sr fixation after treatment with K⁺ solutions. However, cesium was much better reexchanged by K⁺ than by Ca⁺⁺ and Ba⁺⁺ ions. This led to the conclusion that Cs fixed in interlayer positions of clay minerals could be remobilized by potassium and ammonium fertilization. The naturally-occuring Cs contents of the soils were found to be below the detection limit of the analytical methods used. The contents of naturally-occuring exchangeable Sr, however, was in agreement with the amounts of “labile Sr” as derived from the Sr/Ca exchange curves. Concerning the cesium exchange properties a clear distinction between “sea and river marsh soils” on the one hand and “brackish marsh soils” on the other hand was established due to differences in clay mineral composition and swelling state of 1:2 layer silicates. The different cesium exchange properties of the two soil groups could also be verified by more or less pronounced hysteresis effects of sorption (Q/I relation) and desorption curves.  相似文献   

Response of soil exchangeable and crop potassium concentrations to variable fertilizer and cropping regimes in long-term field experiments on different soil types     

S. Andersson    M. Simonsson    L. Mattsson    A. C. Edwards  & I. Öborn 《Soil Use and Management》2007,23(1):10-19

Annual potassium (K) balances have been calculated over a 40‐year period for five field experiments located on varying parent materials (from loamy sand to clay) in south and central Sweden. Each experiment consisted of a number of K fertilizer regimes and was divided into two crop rotations, mixed arable/livestock (I) and arable only (II). Annual calculations were based on data for K inputs through manure and fertilizer, and outputs in crop removal. Plots receiving no K fertilizer showed negative K balances which ranged from 30 to 65 kg ha^?1 year^?1 in rotation I, compared with 10–26 kg ha^?1 year^?1 for rotation II. On sandy loam and clay soils, the K yield of nil K plots (rotation I) increased significantly with time during the experimental period indicating increasing release of K from soil minerals, uptake from deeper soil horizons and/or depletion of exchangeable soil K (K_ex). Significant depletion of K_ex in the topsoil was only found in the loamy sand indicating a K supply from internal sources in the sandy loam and clay soils. On silty clay and clay soils, a grass/clover ley K concentration of ～2% (dry weight) was maintained during the 40‐year study period on the nil K plots, but on the sandy loam, loam and loamy sand, herbage concentrations were generally less than 2% K.  相似文献   

Kaliumernährung des Tabaks auf einem K-fixierenden nordwestiranischen Boden     

M. Karbachsch 《植物养料与土壤学杂志》1978,141(5):513-522

Potassium nutrition of tobacco on a potassium fixing alluvial soil A field experiment was conducted to study the effects of K-fertilization on potassium uptake by tobacco and the K-dynamics in an alluvial soil rich in clay and carbonate content. It was observed that the amount of exchangeable potassium and the concentration of K in the soil solution increased on fertilization. There were only small changes in exchangeable potassium and significant reduction in the concentration of K in the soil solution during the growth period. Uptake of potassium by plants increased during first month due to its high concentration in soil solution. Decrease in the concentration of potassium after one month caused a rapid reduction in the uptake of potassium by plants (Figure 1). K Fertilization decreases the K-Ca and K-Mg potentials especially during the first month (Table 2) which increase again during the experimental period (because of the slow release of K from the solid phase and its rapid uptake by plants). Where as the concentration of potassium in the soil solution is closely related with K-Ca and K-Mg potentials on the one hand and with K-uptake by plants on the other, no relationship was observed between exchangeable potassium content and K-uptake (Figure 2). The potassium exchange curves of soils from K₀ and K₅ treatments show that the extent of K-adsorption is greater in K₀ soil. A major part of K adsorbed during the shaking experiment can be easily removed by CaCl₂ solution in K₅soil, where as in K₀ soil a part of adsorbed potassium exists in nonexchangeable form. Illite is the dominant clay mineral in this soil which show wedge type structures (expansible at edges).  相似文献   

Flow and deformation behavior at the microscale of soils from several long‐term potassium fertilization trials in Germany     

Dörthe Holthusen  Stephan Peth  Rainer Horn  Thomas Kühn 《植物养料与土壤学杂志》2012,175(4):535-547

The effect of K fertilization on microstructural soil stability is rarely analyzed until now although the ambiguous impact on bulk soil structure was reported quite often, e.g., with regard to higher erodibility on the one hand and higher water storage on the other. Soil material from different long‐term fertilization trials in Germany was examined rheologically by means of an amplitude sweep test where the samples were subjected to oscillating shearing with increasing deflection. The resulting shear stress was recorded, and the maximum stress denoted the maximum shear strength of the sample. Results showed an ambiguous influence of K which depends strongly on the soil properties. On the one hand, an increased ion concentration in the soil solution leads to increasing attractive forces as defined by the DLVO theory and therefore higher shear resistance. With increasing desiccation, K⁺ like other salts can precipitate at the contact areas between particles and lead to cementation. On the other hand, K⁺ as a monovalent ion impedes covalent and ionic bonding between clay minerals which holds true for most of the examined soil types while only sandy soils showed an increase in soil strength due to K fertilization. Potassium depletion further resulted in increased interaction of fertilization with other impact factors, e.g., climate and soil properties. Thus, the destabilizing effect of K⁺ was more pronounced under liming as without liming. Subsequent modeling with selected soil parameters confirmed the high influence of matric potential. The modeling also revealed the interactions with other soil parameters, e.g., pH, oxides, texture, exchangeable cations as well as lack or surplus of K in relation to recommended K content. In conclusion, microstructural stability of soil depends on several soil parameters and requires the inclusion of many chemical and physical soil properties.  相似文献   

Potassium release and fixation in Ferralsols (Oxisols) from Southern Togo   总被引：1，自引：0，他引：1  

R. POSS  J. C. FARDEAU  H. SARAGONIT†  P. QUANTIN‡ 《European Journal of Soil Science》1991,42(4):649-660

Potassium release and fixation were studied on Ferralsols (typic Eutrustox) of Southern Togo both by isotopic exchange with ⁴²K+ ions and by exchange with 1 M ammonium acetate. Experiments were conducted on soil samples taken from surface (0–30 cm) and subsoil (80–100 cm) layers of four plots. These plats, with the same soil type, were subjected to various kinds of use: forest and crops, with or without fertilizers. A single wetting and drying of the soil samples increased the amounts of exchangeable K. This exchangeable K release could stem from clay protonation during drying. However, the K release is insufficient to allow permanent intensive agriculture without K fertilizer addition. Soil samples were therefore treated with KCI in order to study K fixation. About 20% of the applied K was fixed and the percentage increased with wetting and drying. The fixation can be explained by the presence of about 2% of interstratified clay minerals in these kaolinitic soils. Comparison of the kinetic characteristics of the isotopically exchangeable K with the amounts of ammonium exchangeable K revealed the existence of several kinds of exchange site for K ions.  相似文献   

Critical potassium potentials for crops. I. The effect of soil type on the growth of ryegrass and creeping red fescue     

M. B. PAGE  O. TALIBUDEEN 《European Journal of Soil Science》1982,33(2):329-347

The quantity: potential relationships for Ca→K exchange in six soils were evaluated, where potential is defined by ΔG_K,Ca+Mg. Using the percentage K saturation of the CEC as the index of quantity, the Worcester Series soil, rich in hydrous micas, was shown to have the highest concentration of K selective sites, and Newport Series soil, with mainly kaolinitic clay, the lowest. The other soils, containing mainly smectites, had intermediate K selectivities. An algebraic transformation of this relationship to separate the effects of exchangeable K and CEC showed that 0.01 m C_aCl₂ released more K than m ammonium acetate. From the exchangeable K : ΔG relationship, two regions of K buffering were observed for all but the Newport soil, the transition occurring at a mean ΔG_K,Ca+Mg value of ?20.7 kJ mol^?1, signifying the K concentration below which K from ‘perlpheral’ regions of micaceous minerals is released. This may explain why the percentage K saturation of the CEC of a soil cropped exhaustively (without K manuring) in the field does not drop below a minimum value. Based on pot experiments, exhaustion and optimum K potentials (ΔG_exh and ΔG_opt) were derived from second-degree polynomials fitted to the response curves of plant dry matter yield against ΔG_K,Ca+Mg for five soils, the Worcester soil showing little response. ΔG_exh was inversely related to the 2 : 1 layer silicate content of the soil (r²=0.98 and 0.94 for ryegrass and fescue respectively), and similarly, ΔG_opt, to their CEC values (r²=0.74 and 0.77). Potassium uptake was more closely correlated with exchangeable K than with ΔG_opt.  相似文献   

IMPACT OF CONTINUOUS SUGAR BEET CROPPING ON POTASSIUM QUANTITY-INTENSITY PARAMETERS IN CALCAREOUS SOILS     

Abbas Samadi 《Journal of plant nutrition》2013,36(8):1154-1167

One hundred-eighteen surface soil samples (59 samples from cultivated areas and 59 samples from virgin soils) were studied to ascertain if potassium (K) quantity-intensity (Q/I) parameters of the soils are being changed by long-term sugar beet cropping. Long-term cultivation resulted in a significant decline in the equilibrium activity ratio (AR_e ^K) values from 0.012 to 0.0047 (moles/L)^1/2 (a drop of 61%) and from 0.013 to 0.008 (a drop of 38%) in Typic calcixerpts and Typic endoaquepts, respectively. Paired t-test revealed that continuous sugar beet cultivation led to significant changes in the easily exchangeable K (ΔK₀) values from ?0.69 to ?0.28 cmol_c/kg (a rise of 59%) the Typic calcixerepts soils. The highest values for PBC^K were associated with the soil types which had the greatest clay contents and smectite clay minerals. Results suggest that continuous sugar beet cropping caused a great decline in K supplying power of the soils.  相似文献   

中南地区几种地带性土壤的胶体表面性质与14×10^-10m矿物   总被引：1，自引：1，他引：1       下载免费PDF全文

徐凤琳  黄巧云  李学垣 《土壤学报》1991,28(2):146-154

本文研究了中南地区不同纬度带花岗岩母质发育的黄棕壤、红壤、砖红壤的胶体表面性质与粘土矿物组合、14×10^-10m矿物、氧化物的关系。结果表明:(1)黄棕壤、红壤、砖红壤粘粒的阳离子交换量、比表面和内表面占总表面的比例依次减小,这与其高岭石、粘粒氧化物含量依次增加,14×10^-10m矿物含量依次减少有关,且也与14×10^-10m矿物在黄棕壤中主要是蛭石,在红壤中主要是14×10^-10m过渡矿物,砖红壤不含14×10^-10m矿物的结论相符合。(2)在其他矿物类型和含量相近下,14×l0^-10m矿物是蛭石的土壤与14×10^-10m矿物是14×10^-10m过渡矿物的土壤相比,前者的阳离子交换量、比表面、内表面占总表面的比例比后者高些,但土壤的活性酸度弱些,交换性铝含量比后者低些。  相似文献   

Potassium isotherm partitioning based on modified quantity‐intensity relation and potassium buffering characterization of soils of North India     

Shabir A. Bangroo  Nayar A. Kirmani  Mohammad A. Bhat  Javaid A. Wani  Asif M. Iqbal  Zahoor A. Dar  Syed Sheraz Mahdi  Ajaz A. Malik 《植物养料与土壤学杂志》2021,184(1):112-122

Background : Potassium (K) availability in soil and plant uptake is restrained by the dynamic interactions among the different pools of K. Aims : To understand these interactions, a study was undertaken to assess the quantity–intensity (Q/I) and buffering characteristics of rainfed maize (Zea mays L.) growing soils. Ten contrasting soils were evaluated for K partitioning changes in exchangeable K (ΔEK) and non‐exchangeable K (ΔNEK) pools in the soil‐solution phase and buffering characteristics using a modified version of Q/I approach. Results : The partitioned Q/I isotherms showed strong adsorption with the increase in K concentration ratio (CR^K) and the changes due to ΔEK were higher than changes due to ΔNEK. Total buffering capacity (PBC^K) significantly correlated (r = 0.92, p <0.01) with clay content with a major share contributed by buffering capacity owing to non‐exchangeable K ( ${\mathrm{PBC}}_{\Delta \mathrm{NEK}}^K$) rather than exchangeable K ( ${\mathrm{PBC}}_{\Delta \mathrm{EK}}^K$). The fixation capacity (β) factor, the magnitude of added K converted into a non‐exchangeable pool, ranged from 41 to 63%, whereas release (α) factor, the magnitude of added K converted to the exchangeable pool, ranged from 19 to 36%. Both threshold solution K (CK_r) and threshold exchangeable K (EK_r) values were found to be high in Satran clay loam (S2) and lower in Doon silty clay loam (S3) soils. The equilibrium exchangeable K (EK_o) was found close to minimum exchangeable K (E_min) in Doon silty clay loam (S3) and Babaweyl sandy clay loam (S1) soils and overall E_min constituted about 8.94 to 0.57% of the EK_o. Conclusion : It may be concluded that K Q/I isotherm partitioning provides a valuable insight to assess the dynamic relations. The ratio of α/β (K recharge index) could be used to evaluate the K enrichment capacity of soil to K additions while EK_r and E_min can be potentially useful in the elucidation of exchangeable K as K fertility index especially in soils with poor K fertilizer management.  相似文献   

CALCIUM: ALUMINIUM EXCHANGE EQUILIBRIA IN CLAY MINERALS AND ACID SOILS1     

B. S. COULTER  O. TALIBUDEEN 《European Journal of Soil Science》1968,19(2):237-250

Exchange reactions between 0.0in AlCl₃ solutions of different pH and Ca-saturated montmorillonite, vermiculite, illite, and soils from the Park Grass Experiment at Rothamsted and the Deerpark Experiment, Wexford, Ireland, showed that Al³⁺ and Al(OH)₂⁺ were adsorbed from solutions of pH > 4.0 and Al³⁺ and H⁺ from solutions of pH < 3.0. When Al was adsorbed, the cation exchange capacity of Ca-saturated soils and clays increased. Conventional Ca: Al exchange isotherms showed that Al³⁺ was strongly preferred to Ca²⁺ on all soils and clays. The equilibrium constant for Ca: Al exchange, K, was identical for soils before and after oxidizing their organic matter and did not vary, for any exchanger, with Al-saturation or the initial pH of the AlCl₃ solution. This proved the validity of the procedure used for calculating exchangeable Al³⁺. K values for Ca:Al exchange favoured Al³⁺ in the order: vermiculite > Park Grass soil > Deerpark soil > illite > montmorillonite. The influence of surface-charge densities of the clay minerals on this order is discussed and a method proposed and tested for calculating the K value of a soil from its mineralogical composition.  相似文献   

Mutual relationships of biochar and soil pH,CEC, and exchangeable base cations in a model laboratory experiment     

Hailegnaw  Niguss Solomon  Mercl  Filip  Pračke  Kateřina  Száková  Jiřina  Tlustoš  Pavel 《Journal of Soils and Sediments》2019,19(5):2405-2416

Purpose

The majority of biochar studies use soils with only a narrow range of properties making generalizations about the effects of biochar on soils difficult. In this study, we aimed to identify soil properties that determine the performance of biochar produced at high temperature (700 °C) on soil pH, cation exchange capacity (CEC), and exchangeable base cation (Ca²⁺, K⁺, and Mg²⁺) content across a wide range of soil physicochemical properties.

Materials and methods

Ten distinct soils with varying physicochemical properties were incubated for 12 weeks with four rates of biochar application (0.5, 2, 4, and 8% w/w). Soil pH, CEC, and exchangeable base cations (Ca²⁺, K⁺, and Mg²⁺) were determined on the 7th and 84th day of incubation.

Results and discussion

Our results indicate that the highest biochar application rate (8%) was more effective at altering soil properties than lower biochar rates. Application of 8% biochar increased pH significantly in all incubated soils, with the increment ranging up to 1.17 pH unit. Biochar induced both an increment and a decline in soil CEC ranging up to 35.4 and 7.9%, respectively, at a biochar application rate of 8%. Similarly, biochar induced increments in exchangeable Ca²⁺ up to 38.6% and declines up to 11.4%, at an 8% biochar application rate. The increment in CEC and exchangeable Ca²⁺ content was found in soils with lower starting exchangeable Ca²⁺ contents than the biochar added, while decreases were observed in soils with higher exchangeable Ca²⁺ contents than the biochar. The original pH, CEC, exchangeable Ca²⁺, and texture of the soils represented the most crucial factors for determining the amount of change in soil pH, CEC, and exchangeable Ca²⁺ content.

Conclusions

Our findings clearly demonstrate that application of a uniform biochar to a range of soils under equivalent environmental conditions induced two contradicting effects on soil properties including soil CEC and exchangeable Ca²⁺ content. Therefore, knowledge of both biochar and soil properties will substantially improve prediction of biochar application efficiency to improve soil properties. Among important soil properties, soil exchangeable Ca²⁺ content is the primary factor controlling the direction of biochar-induced change in soil CEC and exchangeable Ca²⁺ content. Generally, biochar can induce changes in soil pH, CEC, and exchangeable Ca²⁺, K⁺, and Mg²⁺ with the effectiveness and magnitude of change closely related to the soil’s original properties.

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Nutrient disturbances in forest trees and the nature of the forest decline in Quebec and Germany     

George H. Tomlinson 《Water, air, and soil pollution》1990,54(1):61-74

The serious decline of forest trees in Quebec and adjacent areas of the U.S. parallel those observed in Germany. In certain locations, in both cases, K deficiency is now occurring on glacial tills and outwash soils and is associated with a low concentration of exchangeable K⁺ and a high molar ratio of exchangeable Ca⁺ ions to K⁺ ions in the soil. This deficiency results from the so-called Ca-K antagonism in which an increased concentration of Ca²⁺ ions blocks the entry of a reduced concentration of K. Mg deficiency is occurring on granitic soils and results from a low concentration of exchangeable Mg²⁺ and a high molar ratio of A1³⁺ ions to Mg²⁺ ions. The role of the parent rock, weathering reactions and atmospheric inputs are discussed in relation to the changes that have resulted from the cumulative effect of acid deposition. The changes in storage, transfer and losses of cationic nutrients in soil and trees can explain the development of these imbalances, which are still increasing, and are resulting in these forest declines.  相似文献   

Quantity‐intensity parameters of potassium in relation to uptake by guinea‐corn in representative soils of the ecological zones of Nigeria     

《Communications in Soil Science and Plant Analysis》2012,43(19-20):2695-2710

Abstract

Quantity‐intensity (Q‐I) relation studies were often used to supplement information obtained from conventional soil tests for the estimation of potassium (K) needs of crops. With a view to ascertaining the reliability of the Q‐I relation parameters for comprehensive characterization of K dynamics in typical Nigerian soils, K values derived from Q‐I isotherms were related to neutral normal ammonium acetate (1 N NH₄OAc, pH 7.0) (exchangeable) K, other soil K forms [non‐exchangeable (K_ne), exchange (K_e), mineral K (K _m ), and solution K (K_s)] and the K uptake by Guinea‐corn (Sorghum bicolor, var. LS 187) subjected to weekly cuts in Neubauer cultivation vessels. Most of the soil K (about 98%) was in the form of soil minerals while less than 1% was plant available whereas about 1% was trapped within the interlattice layers of the clay minerals (as fixed K or K_ne). Mineral K (K_m) content was closely related to total K (K_t), but not to the other forms, K_ne, K_e, and K_s. A close relationship was noted between the two components of labile K (K_e and K_s). Except for % K saturation, the relationships between the K measurements with plant response were poor. The results of these investigations clearly demonstrate that the Q‐I relation could not adequately characterize the K dynamics of these tropical soils.  相似文献