Effect Of Cation Exchange Capacity Research Articles

Effects of Cation Exchange Capacity and Dissolved Organic Matter of Soil Amendments on Chemical Forms of Heavy Metals in Soils

Effects of Cation Exchange Capacity and Dissolved Organic Matter of Soil Amendments on Chemical Forms of Heavy Metals in Soils

The Influence of Mineralogy and Cation Exchange Capacity toward Electrical Resistivity Value

Electrical Resistivity Tomography (ERT) is a method used for subsurface profiling in soil to characterize soil thickness, fracture zones, soil saturation, salinity and groundwater based on the electrical resistivity value (ERV). There are multiple factors that influence the electrical resistivity value, such as the porosity, degree of saturation, mineralogy, density, cation exchange capacity (CEC), and water resistivity. For this study, the effect of CEC towards resistivity value is studied via controlling the mineralogy factor, saturation, porosity and water resistivity. Thus, via understanding the CEC factor able to relate the resistivity and mineralogy of soil. This study is using a few common minerals in soil and rock, such as kaolinite, montmorillonite, illite, quartz, mica, and feldspar. The particle sizes of all tested minerals were passing 0.063mm sieve. The basic index properties of minerals such as particle size distribution, specific gravity, and Atterberg limit were tested. The instruments of Terrameter LS2 and resistivity box were used to determine the resistivity value of minerals. The Atomic Absorption Spectroscopy (AAS) machine was used to analyze the CEC of minerals via dilute with the ammonium acetate solution. The porosity and degree of saturation of minerals mixed with distill water were controlled between the range of 0.5 to 0.6 and 20% to 100%. The CEC of each mineral has different value, where the lowest and the highest minerals CEC in this study were Kaolinite and Montmorillonite at 1 and 70, respectively. The electrical resistivity values decrease with the increasing of CEC value and degree of saturation. The mineral that has higher CEC indicates lower resistivity value. Meanwhile, via increasing the degree of saturation of minerals were decrease its resistivity values.

Classification, physicochemical, soil fertility, and relationship to Coffee robusta yield in soil map unit selected

The research was aimed (1) to classify, characterize the physicochemical properties, determine the fertility of the soil, and (2) to obtain the relationship of soil fertility on the character yield for Coffee robusta in the 10 units of the soil map (SMUs) selected in Silima Pungga-Pungga Sub-district, Dairi District. This research was conducted in Silima Pungga-Pungga sub-District, Dairi District, North Sumatra Province, Indonesia with coordinates 2080’-2088’NL and 98004’-98017'EL from July 2014 until June 2017. This research was conducted by overlay the maps, classifying soil profiles, characterizing soil, soil fertility assessing, and regression analysis of soil fertility with the yield for Coffee robusta using IBM SPSS Statistics v.20 software. The result showed the ten from 18 SMUs selected for Coffee robusta in Silima Pungga-Pungga sub-District, Dairi District, and has the highest land area sequentially, such as SMU 11, 14, and 1. Based on the ten SMUs selected, found in two representative soil profiles, include the profile 1 (SMU 1, 2, 8, 9, 11, 13, 14, 16, 18) covering an area of ​​1,703.30 ha with the inceptisol and profile 10 (SMU 10) covering an area of 176.81 ha with the entisol. Inceptisol order has greater the soil physicochemical properties compared to entisol from ten SMUs selected for Coffee robusta. The effect of cation exchange capacity, base saturation, P-total, K-total, and C-organic have significantly increased the productivity Coffee robusta by 89.30%, however the effect was not significant to the 100 grains of dry weight. Key words: Entisol; Coffee robusta; Inceptisol; Overlay; Soil fertility.

A nanoscopic hydro-thermo-mechanical model for nuclear waste shale/clay repositories

Shales or highly compacted engineered clay layers are being used as buffers in deep surface nuclear waste repositories. Due to the complex natural structure and fabric of clay and non-clay minerals associated with high in situ stresses, high temperatures, and the practical difficulties in the replication of the field stress and temperature conditions in the lab testing facilities, swell potential from the macro and micro investigations does not provide reliable and universally applicable results. In this study, a comprehensive molecular-level simulation-based volume change constitutive model has been developed for clay minerals incorporating the effects of cation exchange capacity, density, water content, in situ stress state, temperature, exchangeable-cations type and proportion, pore fluids, and the dissolved salts. The molecular simulations were performed using molecular mechanics, molecular dynamics, and Monte Carlo simulation techniques. Comparing the model predictions with the results of the lab tests, the model has been proven to be quite precise in the prediction of the swell potential of these strata under various overburden pressures and temperatures. There is several fold increase in swelling of clay samples at 80 °C as compared to the equivalent specimen tested at 25 °C. The effect of higher temperature is lesser at lower initial water content (higher density) while at higher water content (lower density) the structure has been found to be more vulnerable at higher temperatures. About 100 times higher confining pressure results in the same swell at 80 °C as in its counterpart specimen at 25 °C, the corresponding swell increase factor in case of 50 °C specimens is about 45. A sharp increase in swelling with a drop in in situ pressure emphasizes the probability of higher swell as a result of an accidental reduction in in situ pressure such as the higher concentration of nuclear reactions. In this study, the cohesive energy density (CED) was found to be highly sensitive to various volume change variables, such as water content, density, CEC, type, and percentage of exchangeable and non-exchangeable cations. Contrary to all the previous models, CED-based model developed in this study is universal in nature and can be adopted for any case with minimal basic material input parameters. The good agreement found between the predicted and real values for the swell potential of the undisturbed samples suggests that the model presented here can effectively be used for the assessment of the swelling potential of shale/clay deposits to be used as buffers to the nuclear waste storage.

Enhanced Sweep Efficiency by Use of Smart Water in Tight Oil Reservoirs

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 185032, “Enhance Microscopic Sweep Efficiency by Use of Smart Water in Tight and Very Tight Oil Reservoirs,” by T. Kadeethum, H.K. Sarma, and B.B. Maini, University of Calgary, prepared for the 2017 SPE Canada Unconventional Resources Conference, Calgary, 15–16 February. The paper has not been peer reviewed. In the literature, improvement of oil recovery in smart-water-injection schemes has been shown to be mediated by wettability alteration. This process reduces residual oil saturation, which, in turn, affects microscopic sweep efficiency and leads to subsequent enhancement of overall waterflood performance. Currently, there are few studies on smart waterflooding in tight and very tight oil reservoirs. This work examines smart-waterflood opportunities in such reservoirs. Introduction Residual-oil-saturation reduction improves microscopic sweep efficiency and, therefore, overall waterflood performance. Furthermore, decreasing endpoint water relative permeability diminishes mobility of the water phase such that water production is similarly reduced. Though these circumstances improve oil-production behavior, the primary parameters that lead to this improvement are still not well-understood. Among the statistically significant parameters that can influence smart-waterflood performance is clay content. One plausible explanation for the strong correlation between clay content and oil recovery is the positive correlation between cation-exchange capacity (CEC) and clay content. With higher CEC values, more rock surface may be charged. This results in either the expansion or compression of the double layer, which also induces a wettability alteration. Although tight oil reservoirs have limited flow capability, high CEC values in these reservoirs facilitate the wettability-alteration process. The objectives of the complete paper are to ex-amine the smart-waterflood potential in tight and very tight oil reservoirs, and to identify the CEC effect on smart-water-injection performance. The complete paper provides a discussion of the methodology (procedures and strategies) of the study. Discussion The literature contains evidence of smart-waterflood performance, with some works demonstrating that smart water improves oil recovery by reducing residual oil saturation. Furthermore, it decreases the endpoint water relative permeability. Smart water also improves microscopic sweep efficiency, leading to overall waterflooding efficiency. There is a distinct effect of porosity mean and porosity variance on CEC; there is furthermore a profound effect of CEC upon smart-water performance. Simulation properties relevant to the CEC effect are shown in Table 3 of the complete paper. There are two main types of fluid composition: in-situ fluid composition, which is the initial fluid in the reservoir at timestep zero, and the injected-fluid composition, which is the fluid that is forced into the reservoir at timestep greater than zero. Three homogeneous-reservoir cases with varying CEC values are considered.

Role of clays in fouling-resistant clay-embedded polyelectrolyte multilayer membranes for wastewater effluent treatment

ABSTRACTThis study aimed to investigate the effects of cation exchange capacity (CEC) and location of clay nanoplatelets on the structure and performance of clay-embedded polyelectrolyte multilayer (c-PEM) membranes for wastewater effluent treatment. Two kinds of clay nanoplatelets, montmorillonite and kaolin, were deposited on the ultrafiltration membrane by employing layer-by-layer (LbL) assembly with poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA). Negatively charged clay platelets or PAA interacted with positively charged PAH to form a bilayer in the c-PEM membrane. The filtration effect of clay platelets was successively distinguished from PEM by reducing the number of (PAH/PAA) bilayers from four to one, while keeping the clay layer at the outermost layer of assembly. When the clay platelets were deposited only as the outermost layer of the LbL multilayers, the c-PEM membrane with one clay layer and one bilayer assembly showed significant flux barrier and fouling resistance. Clay platelets as the outermost layer physically increased the flow path length and decreased the number of pores, as well as effectively blocked the organic contaminants in the wastewater. Meanwhile, when the clay layer was embedded in the middle of the PEM, the synergistic effect of clay platelets and PEM for wastewater treatment was difficult to obtain because the presence of clay platelets defected the buildup of fully interdigitated c-PEM and the adsorption of clay platelets was decreased. For the clays having low CEC, a higher number of LbL multilayers were required to deposit the clay platelets and to improve the performance of membrane. The high CEC clays (montmorillonite) turned out to be better than the low CEC clays (kaolin) in the structure and performance of the c-PEM membrane for wastewater effluent treatment.

A universal nanoscopic swell behavior model for gas shales

Hydraulic fracturing to tap unconventional shale gas reservoirs causes a volume change of the active clay minerals matrix in the gas shale structure, resulting in the clogging of the tiny nanopores and consequently undermining the production of the shale gas. Due to the complex natural structure and fabric of clay and non-clay minerals associated with high in-situ stresses at pre and post-fracking and the practical difficulties in the replication of the field stress conditions in the lab testing facilities, swell potential from the macro and micro investigations do not provide reliable and universally applicable results. None of the existing macro level and few molecular-level studies incorporate simulations cover natural structure of gas shales. In this study, we present comprehensive molecular level simulations based volume change constitutive model for clay minerals combining the effects of cation exchange capacity, density, water content, in-situ stress state, exchangeable-cations type and proportion, pore fluids, and the dissolved salts. Although in this paper, the developed protocol have been demonstrated for the gas shales, it can equally be used for several other fields involving the use of clay minerals such as agriculture, medicine, petroleum, environment, and geotechnical engineering.

Selective preparation of zeolite X and A from flyash and its use as catalyst for biodiesel production

This work discusses the utilization of flyash for synthesis of heterogeneous catalyst for transesterification. Different types of zeolites were synthesized from alkali fusion followed by hydrothermal treatment of coal flyash as source material. The synthesis conditions were optimized to obtain highly crystalline zeolite based on degree of crystallinity and cation exchange capacity (CEC). The effect of CEC, acid treatment, Si/Al ratio and calcination temperature (800, 900 and 1000°C) on zeolite formation was also studied. Pure, single phase and highly crystalline zeolite was obtained at flyash/NaOH ratio (1:1.2), fusion temperature (550°C), fusion time (1h), hydrothermal temperature (110°C) and hydrothermal time (12h). The synthesized zeolite was ion-exchanged with potassium and was used as catalyst for transesterification of mustard oil to obtain a maximum conversion of 84.6% with 5wt% catalyst concentration, 12:1 methanol to oil molar ratio, reaction time of 7h at 65°C. The catalyst was reused for 3 times with marginal reduction in activity.

Effect of cation exchange capacity of soil on stabilized soil strength

While a certain correlation between the cation exchange capacity (CEC) of the soil and the strength of the cement stabilized soil has been reported, the mechanism remains unclear. In this research, a set of soil samples with different CECs were stabilized with different proportions of cement and calcium hydroxide (Ca(OH)2, CH). The influence of soil CEC on the strength of the stabilized soil was investigated by analyzing the CH saturation in the pore solution and measuring the strength of the stabilized soil specimens. It is revealed that cation exchange in the soil can reduce the CH saturation of the stabilized soil. If the CEC of the soil is too high, the CH in the pore solution of the stabilized soil cannot reach the saturation level, and further cation exchange would then consume the Ca2+ ions which should be originally used to generate calcium silicate hydrate, thus result in the poor strength of the stabilized soil.

Dispersion and rheology of polypropylene/organoclay nanocomposites: effect of cation exchange capacity and number of alkyl tails

Nanocomposites of montmorillonite organoclays and polypropylene (PP) were prepared via direct melt intercalation using maleic anhydride functionalized polypropylene (PP-g-MA) as a compatibilizer. Two montmorillonite clays (MMT) with different cation exchange capacities (CEC) were exchanged with alkyl ammonium ions, in which one or two octadecyl chains are attached to the nitrogen atom. The role of alkyl chain numbers and CEC value on the dispersion of clay and rheology of PP nanocomposites under shear and extensional flow was evaluated by X-ray diffraction, scanning electron microscopy, and rheologic techniques. It was found that the low-CEC organoclay with one alkyl chain could only form a conventional composite. However, the low-CEC organoclay with two alkyl chains or high-CEC organoclay with one alkyl chain can disperse finely in the matrix. Nanocomposites containing these two organoclays showed typical shear rheologic properties of intercalated nanocomposites, but only the former showed a mild strain-hardening behavior in uniaxial extensional flow. When using an intercalant with two tails, the high-CEC clay would lead the organoclay to form mixed structures which further resulted in an inferior dispersion quality. It was proposed that the dispersion quality and rheologic properties of nanocomposites were related to the arrangement of modifier molecules in the clay galleries, which was determined by the CEC of clay and the structure of alkyl ammonium ions.

Study of nylon 66–clay nanocomposites via condensation polymerization

Nylon 66–clay (polyamide 66 (PA66)–organophilic montmorillonite (OMT)) exfoliated nanocomposites were synthesized based on nylon 66 salt and organoclay (OMT) modified by hydro-aminocaproic acid via condensation polymerization. And the nanocomposites were characterized by X-ray diffraction and transmission electronic microscopy. Exfoliated morphology with different clay content was obtained. The effects of cation exchange capacity and organic modified agent of OMT on the formation of exfoliated nanocomposites were investigated. It was shown that only suitable cation exchange capacity and organic modified agent could result in the formation of exfoliated morphology under the condition of condensation polymerization. The thermal and flammability properties of the nanocomposites were investigated through thermogravimetry and cone calorimetry experiments. Results indicate that the exfoliated nanocomposites have enhanced thermal stability and flame retardant properties compared with pure PA66.

Potassium in soils cropped with sugarcane in mauritius

In view of the importance of potassium (K) in sugarcane production, a study was initiated to broaden current understanding of the K in the soils of Mauritius. Water soluble, exchangeable and non-exchangeable K as well as the 0.1 M H2SO4 extractible K (extraction in 0.1M H2SO4 is used to give a measure of long term K availability in soils of Mauritius) were determined before and after K fertilization with 1.25 g K kg-l soil (equivalent to 350 kg KCl ha-l ) in 73 soils under sugarcane in Mauritius. The rate of K release with time was also studied in the soils receiving the added KCl. The results before K application showed low values of water soluble, exchangeable and non-exchangeable K irrespective of soils. The actual values depended upon the nature of the soils and upon the climatic zone where they were located. Though the values obtained were not comparable to levels in soils of the temperate regions, they were nevertheless of similar order of magnitude to those reported for soils of tropical areas. Upon fertilization with the equivalent of 350 kg KCl ha-l, the levels of water soluble, exchangeable and non-exchangeable K were enhanced with partitioning of the added K following the trend non-exchangeable K > exchangeable K > water soluble K. In general almost half of the fertilizer K served to enrich the non-exchangeable K component in the soils. The extent of the enrichment in non-exchangeable K depended upon the combined effects of cation exchange capacity, the clay content and mineralogy. In spite of the shift toward non-exchangeable K forms, the entire K added was extractible in 0.1 M H2SO4 indicating that all the K applied to the soils as fertilizer would in the long term remain available to sugarcane. The release of the non-exchangeable K in the soils was initially fast but slowed down after two weeks to a near constant rate ranging from 10 to 100 kg K ha-l week-l. Though a number of mathematical equations have been successfully used elsewhere to describe the kinetics of K release in soils, none of them satisfactorily predicted the non-exchangeable K release in Mauritius. The present study showed that to refine K fertilizer recommendations to sugarcane in Mauritius, the K release rate in the soils must be taken into consideration.

Effect of cation exchange capacity on the structure and dynamics of poly(ethylene oxide) in Li+ montmorillonite nanocomposites

AbstractMolecular dynamics computer simulations are used to study the structure and dynamics of 1‐nm wide films of poly(ethylene oxide) (PEO) confined between mica‐type layered silicates of different cation exchange capacities (CEC). The simulation setup mimics experimental systems formed by intercalation of PEO in montmorillonite alumino‐silicates with varied inherent charges. It is shown that the presence and population of lithium has a significant influence on the behavior of the system, in addition to the confinement‐induced effects caused by the extreme spatial restriction. The structural features of the confined PEO are strongly altered with the number of Li+, which determines the polymer/inorganic interactions. The combination of the nanoconfinement and the presence of lithium preclude regular ordered arrangements of PEO, similar to those observed in the bulk unconfined polymer. The segmental dynamics of PEO in confinement are also greatly influenced by the presence of lithium, because of the strong interaction between Li+ and the oxygen of the PEO backbone. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3460–3477, 2005

Cadmium Sorption Behavior in Some Highly Calcareous Soils of Iran

Cadmium (Cd) sorption by selected calcareous soils with a wide range of soil physical and chemical properties was investigated. Two-gram samples of each soil were equilibrated for 24 h with 40 mL 0.01 M CaCl2 containing 5 to 500 mg Cd L−1. The Cd sorption data well fits to Freundlich, two-surface Langmuir and Temkin adsorption isotherms. However, the fit to Langmuir adsorption model was closer than that of Freundlich or Temkin. The Freundlich coefficient (k) was significantly correlated with cation exchange capacity (CEC), calcium carbonate equivalent (CCE), and clay content (Clay). The slope in the first surface was greater than that of the second surface, indicating a higher rate of Cd sorption at low Cd equilibrium concentrations and a proportionally smaller increase in Cd retention at higher initial Cd solution concentrations. Stepwise regression analysis indicated that 67% of the variation in the adsorption maxima of the second surface (b 2) was due to the combined effect of CEC and CCE. Temkin adsorption coefficients, namely k 1 was significantly related to CEC and b 2 was positively correlated with CEC, CCE, and clay content.

PATH COEFFICIENT ANALYSIS OF ZINC AND BORON ADSORPTION IN SOILS

Path coefficient analysis, a statistical technique that differentiates between correlation and causation, was employed to describe zinc (Zn) and boron (B) adsorption on soils. A path analysis model evaluating the effect of clay, free calcium carbonate (CaCO3), organic carbon (OC) and cation exchange capacity (CEC) on Zn and B adsorption as measured by Langmuir adsorption maxima ‘b’ values in surface (0–25 cm) soils possessing varied physico-chemical and mineralogical characteristics was developed. Correlation analysis showed the dominant role of clay and OC, and clay alone in affecting B and Zn adsorption, respectively, while path analysis described the significant direct effect of clay and indirect effect of CEC via clay on Zn adsorption and the significant direct effect of CEC and OC and indirect effect of clay via CEC on B adsorption. Path analysis model constructed for CEC exhibited the significant direct contribution made by clay towards CEC in both the experimental soils, thus, revealing the relationship between CEC and adsorption of Zn and B.

EXCHANGE EQUILIBRIA OF POTASSIUM VERSUS CALCIUM AND SODIUM IN SOILS FROM A SEMIARID REGION, INDIA

We studied the potassium-calcium and potassium-sodium exchange equilibria on three soil samples differing in their organic carbon content (OC) and cation exchange capacity (CEC). Homoionic (Ca or Na saturated) soils were equilibrated, with the solutions having a large range of potassium adsorption ratios (PARs) at 50 meq L-1 total electrolyte concentration. We analyzed the data on exchange equilibria, using a thermodynamic approach and various selectivity coefficients. The normalized exchange isotherms for K+-Ca2+ systems suggested higher specificity for K+ to Ca2+ in the first 50 to 75 percent of K+ saturation. In the K+-Na+ system the specificity for K+ to Na+ was, however, higher for the whole range of exchange isotherms. The soil high in OC (Soil 1) had higher preference for K+ than the soils low in OC (Soils 2 and 3). The values of standard free energy change of the exchange reactions (ΔGr°) for K+-Ca2+ and K+-Na+ systems were negative for all the three soils tested. These values were, however, more negative for K+-Na+ than for K+-Ca2+ systems, suggesting higher preference for K+ in the former. A comparison of ΔGr° values suggested that the effect of CEC on the K+ specificity of these soil samples was only marginal, though that of OC was quite spectacular. The values of the Gapon selectivity coefficient (KG) decreased first sharply and then gradually with the increase in exchangeable potassium percentage (EPP). On the basis of (KG), the exchange isotherms were divided into three zones, representing exchange sites with high, medium, and low specificities for K+. The arbitrary limits for the three zones were < 5, 5 to 38, and >38; > 4, 4 to 15, and >15; and > 5, 5 to 15, and > 15 for Soils 1, 2, and 3, respectively. The exchange selectivity coefficient (KN) and AGr° for K+-Na+ systems were different only marginally for Soils 1 and 2. However, for K+-Ca2+ systems, the values of different selectivity coefficients (viz., KG, Vanselow selectivity coefficient, and Krishnamoorthy-Davis-Overstreet selectivity coefficient) and AGr° for Soils 1 were considerably different from those for Soil 2. This suggested a differential role of OC on changing the selectivity of soil for K+ in K+-Ca2+ and K+-Na+ systems.

The Effect of Cation Exchange Capacity on the Retention of Diquat2+ and Paraquat2+ by Three-Layer Type Clay Minerals I. Adsorption and Release

Diquat (1,1′-ethylene-2,2′-dipyridinium dibromide) and paraquat (1,1′-dimethyl-4,4′-dipyridinium dichloride) were equilibrated for thirty minutes with suspensions of three-layer clay minerals varying in CEC from about 1–1.6 meq/g. Maximum adsorption of the divalent organic cations, expressed as percent of CEC, decreased from 100% for a montmorillonite (CEC = 1.03 meq/g) to 13% for a K+ -depleted muscovite (CEC = 1.63 meq/g). The exchangeable inorganic cation initially present markedly affected adsorption of diquat2+ and paraquat2+ by vermiculite but had much less effect on adsorption by montmorillonite. The order of adsorption was Na+ -vermiculite > Ca2+ -vermiculite ≥ Mg2+ -vermiculite. Less than 15% of the adsorbed diquat2+ or paraquat2+ was released from montmorillonite by a single equilibration with approximately five symmetry of 0.005N chloride salt solutions of Al3+, Ca2+, Mg2+, or K+. Similar treatment of vermiculite released up to 70% of the adsorbed organic cation, the order of release being Al3+ > Ca2+ > Mg2+ > K+ for diquat2+ and Ca2+ > Al3+ > Mg2+ > K+ for paraquat2+. Three successive treatments of vermiculite released up to 89% of the diquat2+ or paraquat2+.

The Effect of Cation-Exchange Capacity on the Retention of Diquat2+ and Paraquat2+ by Three-Layer Type Clay Minerals: II. Plant Availability of Paraquat

Paraquat (1,1′-dimethyl-4,4′-dipyridinium dichloride) was adsorbed on varying amounts of Ca-montmorillonite and Cavermiculite. The herbicide-treated clays were added to a synthetic soil medium and cucumber seedlings (Cucumis sativus) were planted. Ca-montmorillonite effectively reduced the activity of approximately 90 to 95% of the adsorbed paraquat leaving only 5 to 10% available to the plants. Approximately 10% was also found to be exchangeable using 5 × 10-3N AlCl3 solutions and is believed to be that which is adsorbed on external surfaces. The results are analogous to those found with other montmorillonites and suggest that the major portion of dipyridinium herbicides that are adsorbed on this clay mineral is probably adsorbed in a biologically unavailable form. Ca-vermiculite reduced the pbytotoxicity of paraquat, but did not remove the phytotoxic effects completely. Substantial amounts of paraquat were also released from this clay mineral using salt solutions. The results are analogous to previous findings with kaolinite clay and suggest that the adsorption of this herbicide by soils in which vermiculite and kaolinite are the dominant clay minerals is probably largely in a biologically available form.

Effect of Nitrogen to Phosphorus Atom Ratio of Ammonium Phosphates on Emergence of Wheat (Triticum vulgare)1

AbstractAmmonium phosphates providing five N:P atom ratios (1.00, 1.25, 1.50, 1.75, and 2.00:1) were applied in solution in the row with wheat seed at planting in greenhouse experiments. The soils used were Oneida clay loam (CEC 18.3 meq/100 g) and Fox sandy loam (CEC 8.2 meq/100 g) each adjusted to pH levels ranging from 5.4 to 7.4. Soil pH, over the range studied, had no effect on emergence with any of the ammonium phosphate materials tested. Neither early nor final emergence changed when the N:P atom ratio was varied in the clay loam soil when the molarity of the fertilizer solution was held constant (equal rates of P but varying rates of N). In the sandy loam soil early emergence was markedly lower with high N:P atom ratio materials than with low ratio materials. Final emergence showed the same trend as early emergence with the sandy loam soil but differences between materials were much smaller. The difference in results between the two soils is attributed to the effect of cation exchange capacity on the toxicity of ammonia in the soil.

Dynamic Studies on the Nutrient Uptake by Crop Plant. (Part 25) : The Effect of Cation Exchange Capacity of Soil and Plant Root on the Uptake of Some Cations, Particularly of Magnesium

Dynamic Studies on the Nutrient Uptake by Crop Plant. (Part 25) : The Effect of Cation Exchange Capacity of Soil and Plant Root on the Uptake of Some Cations, Particularly of Magnesium