珠江广州河段上覆水和间隙水中磷特性研究

通过研究污染比较严重的珠江广州河段(雅岗至琶洲大桥)的六个断面,共10个采样点的上覆水和间隙水的磷形态分布特征,得上覆水总磷(TP)值为0.705～3.893mg/L,均为劣V类水质。总溶解性磷(TDP)与磷酸盐磷(PO43-)在各采样点的含量分布不均匀,由PO43-含量显示,各采样点已经有明显的富营养化趋势。通过分析各采样点间隙水磷含量和引起其上下层含量差异的环境因素知间隙水TP与TDP有一定相关性。间隙水上下层TP,TDP,PO43-含量差异可能与沉积物有机质和氧化还原环境有一定相关性,总体上认为厌氧环境有利于促进沉积物的磷释放到间隙水。

磷杂螺环化合物的合成及表征

合成了双（４甲撑２，６，７三氧杂１磷杂双环［２，２，２］辛烷）磷酸三聚氰胺盐（Ⅲ）及２，６，７三氧杂１磷杂双环［２，２，２］辛烷甲醇（Ⅰ）、双（４甲撑２，６，７三氧杂１磷杂双环［２，２，２］辛烷）氯代磷酸酯（Ⅱ），三者的得率分别为７２７％、９００％及５７３％；同时对化合物（Ⅰ）、（Ⅱ）及（Ⅲ）的核磁共振碳谱和红外光谱谱图进行了归属和解析。

珠江广州河段上覆水和间隙水中磷的形态分布研究

通过研究污染比较严重的珠江广州河段(雅岗至琶洲大桥)的6个断面,共10个采样点的上覆水和间隙水的磷形态分布特征,得上覆水总磷(TP)值为0.705～3.893mg/L,均为劣吁类水质。总溶解性磷(TDP)与磷酸盐磷(PO43-)在各采样点的浓度分布不均匀,由PO43-浓度显示,各采样点已经有明显的富营养化趋势。通过分析各采样点间隙水磷浓度和引起其上、下层浓度差异的环境因素知间隙水TP与TDP有一定相关性。间隙水上、下层TP,TDP,PO43-浓度差异可能与沉积物有机质和氧化、还原环境有一定相关性,总体上认为厌氧环境有利于促进沉积物的磷释放到间隙水。

工厂化养鱼实用技术模式研究中水质监测分析报告

本试验是工厂化养鱼实用技术模式研究项目中的一个方面。试验于2002年5月24日至7月25日进行,养殖品种为奥尼罗非鱼和短盖巨脂鲤(亦名淡水白鲳)。初始放鱼量40.0 kg/m3,实验结束时单位水体鱼获量奥尼罗非鱼为78.2 kg/m3,淡水白鲳为82.2 kg/m3。试验期间每两天化验一次,共化验32次,监测8项水质理化指标的变化范围分别为:水温22～30℃、pH值7.36～8.28、溶解氧1.17～8.51 mg/L、氨氮0.79～11.27 mg/L、亚硝酸氮0.551～8.520 mg/L、硝酸氮3.33～42.79 mg/L、磷酸盐磷0.547～9.230 mg/L、碱度257.2～358.2 mg/L。

Thermodynamic study on phosphorus removal from tungstate solution via magnesium salt precipitation method

The thermodynamic equilibrium diagrams of Mg2＋- 3-4PO - ＋4NH -H2O system at 298 K were established based on the thermodynamic calculation. From the diagram, the thermodynamic conditions for removing phosphorus from the tungstate solution by magnesium salt precipitation were obtained. The results show that when the concentration of total magnesium increases from 0.01 mol/L to 1.0 mol/L, the optimal pH for the phosphorus removal by magnesium phosphate decreases from 9.8 to 8.8. The residual concentration of total phosphorus almost keeps the level of 4.0×10-6 mol/L in the system. MgHPO4, Mg3（PO4）2 and the mixture of Mg3（PO4）2 and Mg（OH）2 are stabilized in these system, respectively. However, increasing the total concentration of magnesium has little effect on phosphorus removal by magnesium ammonium phosphate, while it is helpful for phosphorus removal by increasing the total ammonia concentration. The calculated results demonstrate that the residual concentration of total phosphorus can decrease to 5.0×10-7 mol/L as the total concentration of ammonia reaches 5.0 mol/L and the optimal pH value is 9-10. Finally, verification experiments were conducted with home-made ammonium tungstate solution containing 50 g/L WO3 and 13 g/L P. The results show that when the dosage of MgCl2 is 1.1 times of the theoretical amount, the optimum pH for removing phosphorus is 9.5, which matches with the results of the theoretical calculation exactly.

Microbially induced deposition of barium phosphates and its ingredient,morphology and size under different pH values

A phosphate-mineralization microbe was used to induce barium phosphates precipitation, and the precipitates with different types were obtained under different pH values. The average crystallite size of the barium phosphates was calculated by particle size distribution curves, and the size of the products was 33.40, 29. 37, 24. 13, 47.76 and 96. 53 μm when the pH values of the mixed solution are 7, 8, 9, 10 and 11, respectively. The results of X-ray diffraction （XRD） show that the structures of the particles controlled by the mixed solution are mainly BaaPO4 when pH 〈 10; the barium phosphates are synthesized by biological deposition which is the mixture of BaHPO4 and Ba5 （PO4）3OH when pH = 10; when pH = 11, the barium phosphates are also the mixtures, which are Ba5 （PO4）3OH and BaNaPO4. The above results indicate that the phosphate-mineralization microbe can produce a certain enzyme which constantly hydrolyzes phosphate monoester in the mixed solution, and then PO4^3- ions are obtained.

Phosphate-Solubilizing and -Mineralizing Abilities of Bacteria Isolated from Soils

Microorganisms capable of solubilizing and mineralizing phosphorus （P） pools in soils are considered vital in promoting P bioavallability. The study was conducted to screen and isolate inorganic P-solubilizing bacteria （IPSB） and organic P-mineralizing bacteria （OPMB） in soils taken from subtropical flooded and temperate non-flooded soils, and to compare inorganic P-solubilizing and organic P-solubilizing abilities between IPSB and OPMB. Ten OPMB strains were isolated and identified as Bacillus cereus and Bacillus megaterium, and five IPSB strains as B. megaterium, Burkholderia caryophyUi, Pseudomonas cichorii, and Pseudomonas syringae. P-solubilizing and -mineralizing abilities of the strains were measured using the methods taking cellular P into account. The IPSB strains exhibited inorganic P-solubilizing abilities ranging between 25.4-41.7 μg P mL^-1 and organic P-mineralizing abilities between 8.2-17.8μg P mL^-1. Each of the OPMB strains also exhibited both solubilizing and mineralizing abilities varying from 4.4 to 26.5 μg P mL^-1 and from 13.8 to 62.8 μg P mL^-1, respectively. For both IPSB and OPMB strains, most of the P mineralized from the organic P source was incorporated into the bacterial cells as cellular P. A significantly negative linear correlation （P 〈 0.05） was found between culture pH and P solubilized from inorganic P by OPMB strains. The results suggested that P solubilization and mineralization could coexist in the same bacterial strain.

Inoculation with Phosphate-Solubilizing Fungi Diversifies the Bacterial Community in Rhizospheres of Maize and Soybean

Application of phosphate-solubilizing microorganisms (PSMs) has been reported to increase P uptake and plant growth. However, no information is available regarding the ecological consequences of the inoculation with PSMs. The effect of inoculation with phosphate-solubilizing fungal (PSF) isolates Aspergillus niger P39 and Penicillium oxalicum P66 on the bacterial communities in the rhizospheres of maize (Zea mays L. 'Haiyu 6') and soybean (Glycine max Merr. 'Heinong 35') was examined using culture-dependent methods as well as a culture-independent method, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Compared with the control, the number of culturable microbes for soybean was significantly greater with P39, whereas for maize, the same was significantly greater with P66. In addition, a greater number of microbes were found in the rhizosphere of maize compared with soybean. The fingerprint of DGGE for 16S rDNA indicated that inoculation with PSF also increased bacterial communities, with the P66 treatment having higher numbers of DGGE bands and a higher Shannon-Weaver diversity index compared with P39; the composition of the microbial community was also more complex with the P66 treatment. Overall, complex interactions between plant species and exotic PSMs affected the structure of the bacterial community in the rhizosphere, but plant species were more important in determining the bacterial community structure than the introduction of exotic microorganisms.

Characterization of tricalcium phosphate solubilization by Stenotrophomonas maltophilia YC isolated from phosphate mines

The phosphate solubilizing characteristics of a strain YC, which was isolated from phosphate mines (Hubei, China), were studied in National Botanical Research Institute’s phosphate (NBRIP) growth medium containing tricalcium phosphate (TCP) as sole phosphorus (P) source. The strain YC is identified as Stenotrophomonas maltophilia (S. maltophilia) based upon the results of morphologic, physiological and biochemical characteristics and 16S rRNA sequences analysis. The results show that the strain S. maltophilia YC can solubilize TCP and release soluble P in NBRIP growth medium. A positive correlation between concentration of soluble P and population of the isolate and a negative correlation between concentration of soluble P and pH in the culture medium are observed from statistical analysis results. Moreover, gluconic acid is detected in the culture medium by HPLC analysis. It indicates that the isolate can release gluconic acid during the solubilizing experiment, which causes acidification of the culture medium and then TCP solubilization. S. maltophilia YC has a maximal TCP solubilizing capability when using maltose as carbon source and ammonium nitrate as nitrogen source, respectively, in NBRIP growth medium.

Phosphate Distribution and Movement in Soil－Root In－terface Zone：I． The Influence of Transpiration Rate

The experiments were conducted in the artificial climate laboratory using ￣(32)P labelled soil and soil-rootplane system to investigate phosphate distribution and its movement in the soil-root interface zone andtheir relations with phosphate uptake by plant as well as transpiration rate (atmosphere humidity). It wasfound that although the phosphate in the soilroot interface zone was of depletive distribution as a functionC/Co = ax￣b(C/Co is the relative content of fertilizer phosphate in a distance from the root surface x, aand b are the regression constants), and a relative accumulation zone of phosphate within 0.5 mm near theroot surface was often observed especially in the heavier texture soils because of root phosphate secretion.The depletion intensity of phosphate in the soil-root interface zone was in agreement with the phosphateuptake by plants under two humidities very well. However, the effects of air humidity on characteristics ofthe phosphate distribution near wheat or maize root surface were different. Wheat grew better under loweratmosphere humidity while maize, under higher humidity, which caused a more intensive uptake and thusa stronger depletion of phosphate in the rhizosphere. Moreover, the depletion intensity was greater by thebottom or the middle part of wheat roots and by the top or the middle part of maize roots. The depletivedistribution of phosphate in the rhizosphere soil and the relative contribution of phosphate diffusion to plant,which was more than 98% in the cultural experiments, indicated that diffusion was a major process forphosphorus supply to plants.

Phosphate-solubilizing microbes in rhizosphere soils of 19 weeds in southeastern China

Low phosphorus (P) availability is one of the most important factors limiting plant growth in red soils across southeastern China. Many non\|symbiotic microorganisms in rhizosphere can enhance P solubility, but little is known about the magnitude of their phosphorus\|solubilizing ability (PSA) and the difference in phosphorus\|solubilizing microorganisms (PSM) among plant species. The number of phosphorus\|solubilizing microorganisms and their PSA in rhizosphere soils of 19 weed species in a citrus orchard on red soil at Changshan, Zhejiang, China, were investigated. Inorganic P (powdered phosphate rock, PR) and organic P (lecithin, OP) were respectively used as the sole P\|source to examine the PSA of isolated microbes. The PS actinomycetes community varied greatly among the different weed rhizospheres while the PS fungus community showed to be most stable to the weed rhizosphere. The highest number of PR\|PS and OP\|PS bacteria was found in rhizosphere soil of \%Mollugo pentaphyll\%, and the highest number of PR\|PS and OP\|PS actinomycetes was found in rhizosphere soil of \%Polygonum lapathifolium\%. The highest number of PR\|PS fungi was found in \%Erigeron annuus\% and \%Mollugo pentaphyll\% rhizosphere soil, and the highest number of OP\|PS fungi was found in rhizosphere soil of \%Mazus stachydifolius\%. \%Mazus stachydifolius\% showed the strongest PR\|PS ability (6340.75μg) while \%Eragrostis pilosa\% showed the strongest OP\|PS ability (1301.84μg). The PR\|PS ability and OP\|PS ability of \%Mollugo pentaphyll\% was 4432.87μg and 1122.05μg respectively. A significant correlation between the number of PR\|PSM and OP\|PSM was found. Significant correlation was only found between the PR\|PS fungi number and its PSA( r =0.75, P <0.05) and between the number of OP\|PS fungi and its PSA( r =0.87, P <0.01}). It indicated that plant species had significant influence on components of the non\|symbiotic PSM community and their activity in its rhizosphere soil. Fungi play a leading role in phosphorus solubilization in weed rhizopshere. It suggested that weed conservation could benefit soil microbe development in agroecosystems, especially in the initial stage of agroecosystem development because there is less organic carbon in bare soil. The results suggested that weed conservation could increase PSA of PSM.

Dolomite apatite separation by amphoteric collector in presence of bacteria

Bioflotation represents one of the growing trends to enhance the selectivity of conventional flotation processes. It utilizes the micro-organisms to replace or to interact with the chemical reagents to increase the gap between surface properties of similar minerals and to enhance the separation selectivity. In this work, dolomite-phosphate separation was investigated using amphoteric collector （dodecyl-N-carboxyethyl-N-hyroxyethyl-imidazoline） in presence of bacteria. Two types of bacteria, Corynebacterium- diphtheriae-intermedius （CDI）, and Pseudomonas aeruginosa （PA）, were used. The collector-bacteria interaction was characterized by Fourier transform infra-red （FTIR）, frothing height and Zeta potential. The results show that the collector-bacteria interaction improves the flotation selectivity. Although, the PA positively affects the separation results, the CDI cannot lower the MgO to less than 1%. A phosphate content of 0.7% MgO and 31.77% P205 with a recovery of 68% at pH 11, 3.0 kg/t amphoteric collector, 4× 10^7 cells of PA is obtained.

Synergism Among VA Mycorrhiza, Phosphate Solubilizing Bacteria and Rhizobium for Symbiosis with Blackgram (Vigna mungo L.) Under Field Conditions

A field experiment was conducted at the G.B. Pant University Research Station, Ujhani (U.P.) in rainy (Kharif) season of the year 1994-1995 to study the effect of Rhizobium, VAM (vesicular arbuscular myc- orrhiza) and PSB (phosphate solubilizing bacteria) inoculation, with and without P, on blackgram (Vigna mungo L.) seed yield. Phosphorus application in soil with medium P content (5.4 mg kg～1) increased nodu- lation, grain yield, N and P in plant and grain over no phosphorus control. Forty kilograms of P-2O-5 each hactare recorded an increase of 20.6 % in nodule dry weight, significant increases of 0.35 g kg～(-1) in N con- centration and 1.28 g kg～(-1) in P concentration of plant over 20 kg P-2O-5 ha～(-1). Similar significant increases of 0.59 g kg～(-l) in grain yield and 0.54 and 0.23 g kg～(-1) in N and P concentrations of the grain, respectively, over 20 kg P-2O-5 ha～(-1) were also obtained with higher dose. Inoculation of Rhizobium ＋ VAM ＋ PSB at all the stages of plant growth recorded maximum increases in all the parameters studied. Dual inoculation of Rhizobium with either VAM or PSB was generally significant in the effect and better than that of VAM ＋ PSB, however, P accumulation in plant and grain was more with VAM ＋ PSB. Among single inocula tions, Rhizobium gave highest and 21.0 % more nodule number, 34.7 % more nodule dry mass, 0.73 g kg～(-1) more N in grain and 4.2 % higher grain yield over PSB. PSB, however, registered significant increases in P concentration in plant and grain over VAM and Rhizobium.

Adsorption of Acid Phosphatase on Minerals and Soil Colloids in Presence of Citrate and Phosphate

The aim of this work was to study the influence of phosphate and citrate, which are common inorganic and organic anions in soils, on the adsorption of acid phosphatase by kaolin, goethite and the colloids separated from yellow-brown soil (YBS) and latosol (LS) in central-south China. The YBS colloid has the major clay mineral composition of 1.4 nm mineral, illite and kaolinite while the LS colloid mainly contains kaolinite and oxides. The adsorption isotherm of acid phosphatase on the examined soil colloids and minerals fitted to the Langmuir model. The amount of enzyme adsorbed in the absence of ligands was in the order of YBS colloid > LS colloid > kaolin ≈ goethite. In the presence of phosphate or citrate, the amounts of the enzyme adsorbed followed the sequence YBS colloid > kaolin > LS colloid > goethite. The presence of ligands also decreased the binding energy between the enzyme and soil colloids or minerals. With the increase of ligand concentration from 10 mmol L-1 to 400 m mol L-1, different behaviors for the adsorption of enzyme were found in the colloid and mineral systems studied. A sharp decrease in enzyme adsorption was observed on goethite while gradual decreases of enzyme adsorption were recorded in the two soil colloid systems. However, no any decrease was found for the amount of enzyme adsorbed on kaolin at higher ligand concentrations. When phosphate or citrate was introduced to the system before the addition of enzyme, the ligands usually enhanced the adsorption of enzyme. The results obtained in this study suggested the important role of kaolinite mineral in the adsorption of enzyme molecules in acidic soils in the presence of various ligands.

Alkaline treatment kinetics of calcium phosphate by piezoelectric quartz crystal impedance

Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoelectric quartz crystal impedance （PQCI） technique. The variations of morphology and composition for the alkaline treatment products were characterized by scanning electron microscopy （SEM）, Fourier transform infrared （FT-IR） and X-ray diffraction （XRD）, respectively. The dynamic variations of calcium phosphate can be characterized by the change of equivalent circuit parameters. The results show that the forming process of hydroxyapatite （HA） is composed of three stages： （1） acidic calcium phosphate dissolution; （2） phase transformation; and （3） HA formation. Furthermore, the correlative kinetic equations and parameters are obtained by fitting the static capacitance （C8）-time curves.

Beneficiation study of Eshidiya phosphorites using a rotary triboelectrostatic separator

This study was performed to investigate the feasibility of applying a Rotary Triboelectrostatic Separator（RTS） to the beneficiation of Eshidiya phosphate minerals.RTS separation tests were carried out on phosphatic bed A_1,phosphatic bed A_3 and slime samples.The bed A_1 and slime samples were tested without desliming.Two sets of tests were performed using the A_3 sample： one was performed without desliming and the other with the A_3 sample deslimed.RTS separation tests as initially performed on the bed A_1 and slime samples gave products that had essentially the same P_2O_5 content.This indicated that adsorbed clay particles on the phosphate surface are responsible for the poor separation of un-deslimed phosphates.Better triboelectrostatic separation was observed with the undeslimed A_3 phosphate sample;these tests resulted in a highest product grade of 26%P_2O_5.The deslimed A_3 sample showed far more effective separation than the undeslimed A_3 one.In fact,a concentrate of 34%P_2O_5 was obtained from the triboelectrcstatic separation of deslimed A_3.The results indicate that with deslimed A_3 P_2O_5 recovery was about 65%for a concentrate of 28%P_2O_5 and about 45%for a concentrate of 30%P_2O_5.These results clearly show the importance of desliming for effective beneficiation of phosphate by the RTS.A more efficient separation can be expected from optimized operating conditions and circuit configuration.

Phosphate Rock Fertilizer in Acid Soils: Comparing Phosphate Extraction Methods for Measuring Dissolution

Three phosphate extraction methods were used to investigate the dissolution, availability and transformation of Kunyang phosphate rock (KPR) in two surface acid soils. Dissolution was determined by measuring the increase in the amounts of soluble and adsorbed inorganic phosphate fractions, and did not differ significantly among the three methods. Significant correlations were obtained among P fractions got by the three extraction methods. Dissolution continued until the end of the 90 day incubation period. At the end of the period, much of the applied phosphate recovered in both soils were in the Al and Fe P or in the hydroxide and bicarbonate extractable inorganic P fractions. The dissolution of KPR in the two soils was also similar: increased addition of phosphate rock resulted in decreased dissolution. The similarity in the order and extent of dissolution in the two soils was probably due to the similarity in each soil of several factors that are known to influence phosphate rock dissolution, namely low CEC, pH, P level, and base status; and high clay and free iron and aluminum oxide contents. The results suggested that KPR could be an alternative P source in the long, if not the short, term in the soils, provided that those factors influencing P availability in the soils are not limiting.

Phosphate Distribution and Movement in Soil-Root In-terface Zone: II. The Infinence of Soil Water Contentand Application Rates of Phosphate

The phosphate in the soil-root interface zone under various soil water contents and application rates ofphosphate was still of depletion distribution which could be described by a power function in the form ofC/Co= ax￣b(C/Co is the relative content of fertilized phosphate in a distance from the root surface x, a andb are the regression constants). The depletion rate of phosphate in soil near the root surface was higher andthe depletion range was narrower under lower soil moisture. On the contrary, at higher soil water content thedepletion range was wider, generally The application rate of phosphate led to the greater depletion intensityof phosphorus was higher in the heavier texture soils. In general, the depletion intensity in the soils, whichdecreased with increasing clay content or increa.sing buffering power of soil, decreased in the order as loessalsoil and black fou soil> lou soil> yellow cinnamon soil when 50 or 100 mg of phosphorus were applied in theform of KH_2PO_4. This result indicated that the phosphate distribution and its movement in the soil-rootinterface zone closely related with the buffering capacity of soil.

The Long Term Evolution of Phosphates from the Cambic Chernozem at ARDS Caracal, Romania

The decreasing of the plant available phosphorus of Romanian soils after 1990 is a major concern in relation with the lowered yields of the major crops. This fact is correlated with a rudimentary technology where the fertilization is a secondary issue. Thus, the fertilizer consumption, after 1990, has drastically decreased to 41.3 kg/ha NPK on arable land over 129.9 kg/ha in 1986 and from 86.4 kg/ha to 26.3 kg/ha on agricultural land. As a result, the phosphorus fertilizer quantities applied by small farmers are very small or inexistent. In order to determine the soil available phosphorus content in Romania, it was analyzed the evolution of soil phosphorus supplying degree on a cambic chernozem （one of the most fertile soils in Romania） from Agricultural Research and Development Station （ARDS） Caracal between 1986-1992 and 2000-2005. This analysis has shown the following issues： very well supplied soils by available phosphorus no more exist since 2006, the ones with a good supplying degree have decreased from 616 ha to 107 ha, which means from 24.8% to 4.3% yet the low supplied soils have increased from 526 ha to 1,129 ha （23.1% to 45.5%） and the very low supplied ones have increased from 198 ha to 776 ha （7.9% to 31.2%）. As a consequence of low fertilizer quantities and the decreasing of the soil supplying degree by available phosphorus the average yield in this farm has decreased from 5,776 to 3,707 kg/ha.