共查询到20条相似文献，搜索用时 234 毫秒
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The adsorption of Zn, as compared with Mg, on two mineral soils, which differed in their major cation-exchange materials and with and without Ca-saturation, was measured in the presence of free CaCl2. The adsorption of Zn as well as Mg occurred on cation-exchange sites. The Zn adsorption data conformed to a two-term Langmuir equation. The presence of two kinds of adsorption sites and their numbers and bonding energies were deduced. However, the Langmuir approach was not adopted on the basis of comparison between the total number of the adsorption sites for Zn deduced and the CEC of the soils. As an alternative approach, the selectivity coefficient as defined by the equation: was calculated for each adsorption equilibrium and plotted against the amount of Zn adsorbed. This [Zn]soil plot was used to estimate the capacities of the soil to adsorb Zn with specified affinities. The value varied between 1 and 1,000, whereas the corresponding value varied only between 0.5 and 1. The value was dependent upon the amount of Zn adsorbed, the status of exchangeable cations, and the major cation-exchange materials (montmorillonite VS. allophane-imogolite) in the soils. The importance of surface OH groups in allophane-imogolite as specific adsorption sites for Zn was suggested. 相似文献
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《Soil Science and Plant Nutrition》2013,59(1)
pp. 859–864 Behavior of nitrogen in the media was investigated when the aqueous phase produced by methane fermentation was supplied as liquid fertilizer. When the aqueous phase was supplied to masa-soil, included in masa-soil was nitrified to . Additionally, in masa-soil, absorption was observed. On the other hand, in the case of coconut fiber and rockwool, has been hardly nitrified. From above results, it was determined that toxic effect from the aqueous phase on tomato plants growth was inhibited by means of the progress of nitrification and absorption by masa-soil. However, nitrification was restrained so that was fixed in masa-soil. On the other hand, in the sampled field soil, was not fixed, and was nitrified immediately. In the field soil, there was a great deal of generated . In comparison with masa-soil. 相似文献
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Investigations were carried out on the effect of the activity ratio of potassium to calcium and magnesium in the nutrient solution applied by drip irrigation on the growth and nutrient uptake of lettuce (Lactuca sativa var. Great Lakes 366) grown on Tottori sand dune soil. The of the soil solution was influenced by that of the nutrient solution. Calcium nutrition of lettuce was not influenced by the in the soil solution. However, the magnesium nutrition was improved at a low activity ratio, which resulted in the alleviation of the physiological injury. 相似文献
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Abstract Hattori (1985) proposed a model to simulate the relation between the number of bacterial colonies on agar plates and the incubation time, using the following equation: where N(t) is the number of colonies observed at time t, and N∞ λ, and t r are parameters expressing the expected number of colonies observed at an infinite time, the rate of increase in the number of colonies, and the time of initiation of colony formation, respectively. This model is called the first-order reaction (FOR) model because the Eq. 1 is essentially the same as that of the first-order reaction. 相似文献
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《Soil Science and Plant Nutrition》2013,59(2):228-234
Abstract Phosphite (; Phi), a reduced form of phosphate (; Pi), is widely marketed as either a fungicide or fertilizer or sometimes as a biostimulant. This is confusing for both distributors and growers. The present paper explores data from various studies to clarify that Phi does not provide plant P nutrition and thus cannot complement or substitute Pi at any rate. In addition, Phi itself does not have any beneficial effect on the growth of healthy plants, regardless of whether it is applied alone or in combination with Pi at different ratios or different rates. The effect of Phi on plants is not consistent, but is strongly dependent on the Pi status of the plants. In most cases, the deleterious effect of Phi is evident in Pi-starved, but not Pi-sufficient, plants. Plants fertilized with Pi allowing for approximately 80–90% of its maximum growth might still be at risk of the effect. This negative effect becomes more pronounced under more seriously Pi-deficient conditions. Although a number of studies have shown positive crop responses to Phi, these responses are likely to be attributable to the suppression of plant diseases by Phi and/or to Pi formed from oxidation of Phi by microbes. In addition, indirectly providing P by Phi-to-Pi oxidation is not an effective means of supplying P to plants compared with Pi fertilizer. An understanding of these issues will aid the right selection of fertilizer as well as minimize the harmful effects of Phi use on crops. 相似文献
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A volcanic ash soil consisting of more than 40 layers, of volcanic fallout was studied from the standpoint of humus chemistry. According to soil texture and humic acid type, the soil profile was divided into 3 sections as follows: (1) Upper layers formed since 1779 A.D. Loamy sand. Po or A type. (2) Middle layers formed from 1779 A.D. to 5,540 yr. B.P. Sandy loam, A, A or P type. (3) Lower layers formed from 5,540 yr. B.P. to about 20,000 D.P. Sandy clay, loam or clay loam, A± type. The PQ values in the middle layers were lower than those of the upper and lower layers. The distribution of carbon and nitrogen contents in the fulvic and humic acid and humin fractions of each layer varied considerably. The CfN ratio of the total humus of each layer tended to increase with the increase in its carbon content. C/N ratios of humic acids in the lower layers were higher than those in the upper and middle layers. C/N ratios of fulvic acid fractions were nearly constant (10-13), for all layers examined, and those of humin fractions ranged from 15 to 20, with one exception of 34. The amounts of sugars, uronic acids and amino acids in hydrolysates of fulvic acids were more or less same for all samples, and sum of the amounts of carbon in these compounds comprised 30 to 40 percent of fulvic acid carbon. Amino acid nitrogen comprised 72 to 94 percent of fulvic acid nitrogen. Seven amino acids were detected, among which aspartic acid, glutamic acid and glycine were predominant. 相似文献
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Toshiyuki Wakatsuki Hideaki Furukawa Keizaburo Kawaguchi 《Soil Science and Plant Nutrition》2013,59(4):353-362
The Minimum Concentration for Specific Adsorption (MCSA) was defined as a reversal of the charge concentration of the ion at the infinite dilution of sol (adsorbent), or practically at such concentration of sol that equilibrium of the ion Is but negligibly affected by adsorption of the ion. The MCSAs of 15 species of cations were measured with respect to SiO2 at pH 4,6,5, and 10; the MCSAs of 10 species of anions were measured with respect to Fe(OH)3 at pH 4, and 6.5; and the MCSAs of 10 species of anions were measured with respect to Al-coated-SiO2 at pH 6.5. Relative specificities of the inorganic ions based on the MCSAs at pH 6.5 were as follows: The MCSAs of cations with respect to SiO2 and of anions to Fe(OH)3 and Al-coated-SiO2 at pH 6.5 had close relationships to ionic potentials and general solubility of the elements in water. Based on these results, the authors concluded that the MCSA could be used u an index of specificity (i.e. covalent bond-forming tendency) of an Jon at adsorption reactions. The values corresponding to the apparent stability constants of surface complexes formed by adsorption reaction with SiO2 and cations at pH 4 were calculated from the values of the MCSAs. 相似文献
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Silke Neu Ingo Müller Carsten Brackhage Rafał Gałązka Grzegorz Siebielec Markus Puschenreiter E. Gert Dudel 《Journal of Soils and Sediments》2018,18(6):2259-2270