Calcium-Magnesium Ca/Mg Ratios and Their Agronomic Implications for the Optimization of Phosphate Fertilization in Rainfed Rice Farming on Acidic Ferralsol in the Forest Zone of Ivory Coast

This study is a contribution to improving rice productivity on acidic plateau soils of the tropical rainforest zone. It is based on taking into account the cationic balances of the soil in order to optimize the phosphorus (P) nutrition of rice on these acidic soils, where this nutrient constitutes a limiting factor for agricultural production. Three (3) pot trials were conducted in Adiopodoumé in the forested south of Côte d’Ivoire. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg Ca ha−1) and magnesium sulfate (0, 25, 50 and 75 kg Mg ha−1) were evaluated on the response of NERICA 5 rice at doses 0, 25, 50 and 75 kg P ha−1 of natural phosphate from Togo, applied only once at the start of the experiment. Additional fertilizers of nitrogen (N) (100 kg N ha−1) and potassium (K) (50 kg KCl ha−1) were added to each of the tests in a split-plot device. The test results revealed a paddy production potential of approximately 3 to 5 t⋅ha−1 for NERICA 5 on an acidic soil, under the effect of the interaction of P, Ca and Mg. The quadratic response of rice yield to the doses of these fertilizers would be more dependent on their balance, itself influenced by Ca nutrition. For the sustainability and maintenance of rice production in agro-ecology studied, it was recommended doses of 38 kg Ca ha−1, 34 kg Mg ha−1 in a Ca/Mg ratio (1/1) with intakes of 41 kg P ha−1, overall in a ratio 1/1/1 (P/Ca/Mg) more favorable to the availability of free iron considered a guiding element of mineral nutrition. Thus, these promising results should be confirmed in a real environment for better management of the fertilization of rice cultivated on acidic plateau soils in Côte d’Ivoire.

Investigation of Hexavalent Chromium Reduction in Strong Saline and Acidic Nitro-Phosphate Solutions

Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality. Consequently, robust methods with potential to remove various types of hazardous elements are required. Among such impurities, hexavalent chromium (Cr(VI)) is very likely to become a future challenge. Different industrial ways to treat phosphate rock are currently being practised, and we have here studied how chromium behaves when using the nitro-phosphate process. The reduction mechanism of Cr (VI) in nitric acid and phosphoric acid solutions was investigated by measuring redox potential and UV-VIS spectra. The results show that Cr (VI) is not stable in strong nitric acid solutions. Reduction of Cr (VI) species decreased with decreasing temperature, NO2 concentration, ionic strength and absence of light. These findings support the proposed reduction reaction:The reduction rate was observed proportional to the nitric acid decomposition: .

Effects of Phosphate Fertilizer on Cold Tolerance and Its Related Physiological Parameters in Rice Under Low Temperature Stress

The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on cold tolerance and its related physiological parameters in rice seedings （chilling-sensitive cv. Changbai 9 and chilling-tolerant cv. Jijing 81） under low temperature stress. At the same time, the identification of cold tolerance was conducted. Compared with the normal temperature treatment, the relative chlorophyll content, photosynthesis rate, Fv/Fm and qP decreased and index of unsaturated fatty acid increased in rice under low temperature stress. The effect of chilling-sensitive cultivars was more than that of chilling-tolerant cultivars, more phosphorus fertilizer properly improved seedling quality of rice, slowed relative chlorophyll content dropping degree of rice seeding, increased photosynthesis rate, Fv/Fm, qP and index of unsaturated fatty acids, and enhanced the ability to chilling-tolerant cultivars under low temperature. The effect on chilling-tolerant cultivars was significantly higher than that on chilling sensitive cultivars by applying more phosphorus fertilizer. Phosphate regulated photosynthetic physiology and membrane fluidity to reduce injury by low temperature, and increasd the cold tolerance capacity of rice.

Effects of Nitrogen Fertilizer with Nitrification Inhibitor DMPP (3,4-Dimethylpyrazole phosphate) on Nitrate Accumulation and Quality of Cabbage(Brassica campastris L.ssp. pekinesis)

To assess the effects of N fertilizer ammonium sulphate nitrate [(NH4)2SO4 plus NH4NO3;ASN] with the new nitrification inhibitor (NI) 3, 4-dimethylpyrazole phosphate (DMPP)(ASN+DMPP) on yield, nitrate accumulation, and quality of cabbage (Brassica campastrisL. ssp. pekinesis), two field trials were carried out under various soil-climaticconditions in Jinhua City and Xinchang County, Zhejiang Province of China in 2002.Results showed that DMPP could increase the mean yield by+2.0tha-1 in Jinhua, +5.5tha-1 inXinchang, decrease NO3--N content by -9.4% in Jinhua, -7.3% in Xinchang and improvenutritional quality by increasing vitamin C (VC), soluble sugar, K, Fe, Zn contentssignificantly.

Modii cation ef ect of calcium-magnesia phosphate fertilizer on microstructure and mechanical properties of Mg_2Si/Mg-4Si composite

In order to modify in-situ synthesized Mg_2Si particles in Mg_2Si/Mg-4Si composite, the modif ication effect of calcium-magnesia phosphate fertilizer on primary Mg_2Si phase in Mg_2Si/Mg-4Si composite was investigated by means of X-ray diffraction(XRD), optical microscopy(OM), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS) analysis. The results indicate that the morphology of the primary Mg_2Si phase apparently changes from coarse dendrites to f ine dispersive polygonal particles, and the mean size is decreased from 277 μm to 17 μm. With the addition of 4.0wt.% calcium-magnesia phosphate fertilizer as a modif ier, the ultimate tensile strength and elongation of the Mg_2Si/Mg-4Si composite are increased from 78.7 MPa and 2.1% to 105.2 MPa and 2.6%, as compared to those of the base composite, which is probably attributed to the formation of the phosphorous compound and the cluster of Ca compounds that acted as the heterogeneous nucleation substrates of the primary Mg_2Si particles, resulting in a ref ined distribution of these precipitates.

A Study on the Radioactivity Level in Raw Materials, Final Products and Wastes of the Phosphate Fertilizer Industries in Bangladesh

A study on the detection of probable radionuclides and their activity concentrations in the raw material (phosphate rock), final product (fertilizer) and waste samples collected from all the phosphate fertilizer factories (total two factories—A Diammonium Phosphate, DAP and a Triple Super Phosphate, TSP factory) in Bangladesh were carried out. A total of seven types of samples (grossly divided into solid and liquid types);liquid waste, waste-mixed river water, normal river water, phosphate rock, phosphate fertilizer, solid waste and normal soil;were analyzed under this study. Raw material samples were collected only from the TSP fertilizer factory. Fertilizer, solid and liquid waste samples were collected from both the factories under study. Moreover, normal soil and natural surface water samples from the suitable areas adjacent to the factories were also collected for the comparison purpose. The samples were analyzed by gamma ray spectrometry technique using a Hyper-Pure Germanium (HPGe) detector of 40% relative efficiency. The analysis of the samples showed that only natural radionuclides such as 226Ra, 232Th and 40K were present in the samples and no traces of artificial radioactivity were found in any of the samples. 40K was found below the detection limit in some samples. The analysis of the samples in the case of TSP fertilizer factory showed that the average activity concentrations of 226Ra and 232Th and 40K in raw materials were 851.27 ± 7.10, 19.63 ± 6.57 and 54.06 ± 5.93 Bq/kg, respectively, in final product 211.90 ± 4.74, 42.48 ± 10.56 Bq/kg and ND (Not Detected), respectively, in solid waste 187.49 ± 4.88, 70.06 ± 11.76 and 289.27 ± 40.24 Bq/kg, respectively and in liquid waste 6.26 ± 0.63, 10.01 ± 1.39 Bq/L and ND, respectively. The measured results in the case of samples collected from DAP fertilizer factory showed that the average activity concentrations of 226Ra and 232Th and 40K in the final product were 17.31 ± 3.92, 69.74 ± 9.88 and 48.46 ± 17.22 Bq/kg, respectively, in solid waste 24.47 ± 4.15, 164.62 ± 11.08, 191.52 ± 33.74 Bq/kg, respectively and in liquid waste 3.59 ± 1.05, 37.08 ± 3.30 Bq/L and ND, respectively. Considering the stored raw materials and wastes the part of the ambient environment of the factory, radium equivalent activity, radiation hazard index and external annual effective dose to the workers and public due to these materials were also calculated and compared with world average values.

Study on structural characteristics of pillared clay modified phosphate fertilizers and its increase efficiency mechanism

Three types of new high-efficiency phosphate fertilizers were made when pillared clays at certain proportions were added into ground phosphate rock. Chemical analyses showed that their soluble phosphorus content decreased more than that of superphosphate. Pot experiment showed that, under equal weights, the new fertilizers increased their efficiency by a large margin over that of superphosphate. Researches on their structures by means of XRD, IR and EPR spectrum revealed that their crystal structures changed considerably, improving their activity and preventing the fixation of available phosphorus in the soil, and consequently, greatly improved the bioavailability and became the main cause of the increase of biomass.

Transformation of Phosphate Fertilizers with Different Solubilities in Calcareous Soils

In this research work,the authors,using the recently developed method of fractionating the forms of inorganic phosphorus in calcareous soils,have studied the transformation processes of inorgnic phosphorus in three different phosphate fertilizers,i.e.,superphosphate,diammonium phosphate and calcium magnesium phyosphate,being commonly used in China,during a period of 3 years after their application to calcareous soils,and based on the experimental results obtained,some problems in current use of phosphate fertilizers are discussed.

Study of the Inhibitor Scaling Effect of the Agricultural Water by a Phosphate Fertilizer

The localised irrigation or drop by drop system is a technique which makes it possible to save water, because it ensures a balanced and efficient distribution of water and an effective fertilization. However, this ferti-irrigation system is facing a number of problems hindering the agricultural development. The lack of uniformity of the localised irrigation was observed and found out that it is due to chemical clogging of drippers. Considering the complexity of the composition of the natural water used in micro-irrigation, we started our study by examining the effectiveness of the inhibitor on pure calco-carbonic water with 40°F, and then moved to explore the natural water of the agricultural region. The Legrand-Poirier-Leroy method allowed us to determine the position of the irrigation water compared to calco-carbonic balance. LCGE (abbreviation of “Laboratory of Chemistry and Environmental Engineering”) technique, based on the accelerated formation of calcium carbonate deposit under the effect of a degasification of studied water, enabled us to evaluate the scaling power of this water of irrigation either with or without inhibitor. The experimental results showed the following: in the case of pure calco-carbonic water with 40?F and of natural water, the addition respectively of 2 mg/L and 2.25 mg/L of phosphate fertilizer completely inhibits the precipitation of calcium carbonate under the conditions of the experiment.

Study on Function of Rare Earth During Producing Phosphate Fertilizer by Wet Process

The impacts of the Rare Earth (RE) on the contents of available Phosphorus (P) and the physical character of the calcium superphosphate produced by the wet process on the basis of simulating the consumption of concentrated sulphuric acid, the slurry concentration and the cure conditions in different wet process were studied in laboratory, and the results show that adding RE into different wet process does not raise available P, but changes its physical character,for example, the composite is loose and the color is offwhite.

Effect of Fertilizer Diammonium Phosphate on Liver,Kidney and Muscle 5-Nucleotidase Activity of Fresh Water Teleost Fish Clarias batrachus

The toxic effect of fertilizer Diammonium phosphate resulted in alterations of 5'-Nucleotidase activity of tissues liver, kidney and muscles offish C. batrachus at varying intervals and exposures. Alterations in 5'-Nuclcotidase activity of body organs gave an idea of the toxicity caused by the fertilizer. Thus the enzyme 5'-Nucleotidase can be used to monitor the pollution in aquatic ecosystem.

Effects of Phosphate Fertilizer on Yield and Quality of Eleocharis dulcis

The effects of different application levels and species of phosphatic fertilizer on Eleocharis dulcis were studied. The results showed that the growth stage of Eleocharis dulcis was not significantly influenced by different levels of phosphatic fertilizer application, with phosphorus level in 195-375 kg/hm^2. With increasing of the phosphorus level, starch and total soluble sugar accumulated, but the yield was not improved significantly. The analysis on the economic benefits showed that the best phosphorus level was 195 kg/hm^2. The growth stage and yield of Eleocharis dulcis were not considerably influenced by different proportions of calcium-magnesia phosphate fertilizer and ammonium dihydrogen phosphate. With increasing of ammonium dihydrogen phosphate, big-fruit rate of Eleocharis dulcis kept growing, but the accumulations of starch and total soluble sugar were decreasing.

Polyphosphate Accelerates Transformation of Nonstructural Carbohydrates to Improve Growth of ppk-Expressing Transgenic Rice in Phosphorus Deficiency Culture

Crop yield and quality are often limited by the amount of phosphate fertilizer added to infertile soils,a key limiting factor for sustainable development in modern agriculture.The polyphosphate kinase(ppk)gene-expressing transgenic rice with a single-copy line(ETRS)is constructed to improve phosphate fertilizer utilization efficiency for phosphorus resource conservation.To investigate the potential mechanisms of the increased biomass in ETRS in low phosphate culture,ETRS was cultivated in a low inorganic phosphate(Pi)culture medium(15μmol/L Pi,LP)and a normal Pi culture medium(300μmol/L Pi,CP),respectively.After 89 d of cultivation in different concentrations of phosphate culture media,the total phosphorus,polyphosphate(polyP),biomass,photosynthetic rate,nonstructural carbohydrate(NSC)contents,related enzyme activities,and related gene expression levels were analyzed.The results showed that ETRS had a high polyP amount to promote the photosynthetic rate in LP,and its biomass was almost the same as the wild type(WT)in CP.The NSC content of ETRS in LP was higher than that of WT in LP,but slightly lower than that of WT in CP.PolyP notably promoted the sucrose phosphate synthase activities of ETRS and significantly down-regulated the expression levels of sucrose transporter genes(OsSUT3 and OsSUT4),resulting in inhibiting the transport of sucrose from shoot to root in ETRS.It was concluded that polyP can stimulate the synthesis of NSCs in LP,which improved the growth of ETRS and triggered the biological activities of ETRS to save phosphate fertilizer.Our study provides a new way to improve the utilization rate of phosphate fertilizer in rice production.

Influences of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen and soil salt-ion leaching

An undisturbed heavy clay soil column experiment was conducted to examine the influence of the new nitrification inhibitor, 3,4- dimethylpyrazole phosphate （DMPP）, on nitrogen and soil salt-ion leaching. Regular urea was selected as the nitrogen source in the soil. The results showed that the cumulative leaching losses of soil nitrate-N under the treatment of urea with DMPP were from 57.5% to 63.3% lower than those of the treatment of urea without DMPP. The use of nitrification inhibitors as nitrate leaching retardants may be a proposal in regulations to prevent groundwater contaminant. However, there were no great difference between urea and urea with DMPP treatments on ammonium-N leaching. Moreover, the soil salt-ion leaching losses of Ca^2＋, Mg^2＋, K^＋, and Na^＋ were reduced from 26.6% to 28.8%, 21.3% to 27.8%, 33.3% to 35.5%, and 21.7% to 32.1%, respectively. So, the leaching losses of soil salt-ion were declined for nitrification inhibitor DMPP addition, being beneficial to shallow groundwater protection and growth of crop. These results indicated the possibility of ammonium or ammonium producing compounds using nitrification inhibitor DMPP to control the nitrate and nutrient cation leaching losses, minimizing the risk of nitrate pollution in shallow groundwater.

Effect of Phopshate Fertilizer and Manure on Crop Yield, Soil P Accumulation, and the Environmental Risk Assessment

Phosphorus （P） applied from fertilizer and manure is important in increasing crop yield and soil fertility; however, excessive uses of phosphate fertilizer and manure may also increase P loss from agricultural soils, posing environmental impact. A long term experiment was conducted on a calcareous soil （meadow cinnamon） in Hebei Province, China, from 2003 to 2006 to investigate the effects of phosphate fertilizer and manure on the yield of Chinese cabbage, soil P accumulation, P sorption saturation, soluble P in runoff water, and P leaching. P fertilizer （P2O5） application at a rate of 360 kg ha^-1 or manure of 150 t ha^-1 significantly increased Chinese cabbage yield as compared to the unfertilized control. However, no significant yield response was found with excessive phosphate or manure application. Soil Olsen-P, soluble P, bioavailable P, the degree of phosphorus sorption saturation in top soil layer （0-20 cm）, and soluble P in runoff water increased significantly with the increase of phosphate fertilizer and manure application rates, whereas the maximum phosphorus sorption capacity （Qm） decreased with the phosphate fertilizer and manure application rates. Soil Olsen-P and soluble P also increased significantly in the sub soil layer （20-40 cm） with the high P fertilizer and manure rates. It indicates that excessive P application over crop demand can lead to a high environmental risk owing to the enrichment of soil Olsen-P, soluble P, bioavailable P, and the degree of phosphorus sorption saturation in agricultural soils.

Value Addition to Waste Material Supported by Removal of Available Phosphate from Simulated Brackish Water—A Low Cost Approach

Phosphorus is one of the major nutrients that have been identified as a limited resource that would end up earlier than predicted at the rate of current consumption. Therefore, attempts to recover phosphorus from waste and its subsequent use are a concern of current researchers. Nevertheless, recovery of nutrients from wastewater is cumbersome because nutrients such as phosphates () and nitrates () prefer to remain in aqueous phase rather than being adsorbed on solid matrixes. Investigation of adsorption of available - P from simulated brackish water, on granulated solid waste material, prepared by crushed autoclaved aerated concrete (CAAC), and subsequent use of the material as phosphate fertilizer would be the focus of this research. Treatment of nutrient-rich brackish water is important because such water is discharged in huge volume at the time of harvesting of shrimp aquaculture ponds. Experiments conducted in simulated brackish water confirmed non-linear adsorption association with changing distribution coefficient (KD) which attributed the maximum removal of about 98% - P from 100 mgdm-3solution at its value of 40. The non-linear adsorption supported by both the Langumuir and the Freundlich isotherm models simultaneously satisfied monolayer adsorption and multilayer adsorption depicted by the regression coefficients of greater than .99 by the linearized forms of the isotherm models. Moreover, promising phosphate uptakes characteristics are exhibited by the adsorbent at the process of repetitive adsorption which resulted in 12 g/kg uptake of phosphate at 81% efficiency. The adsorbent seems to be used as a slow-released phosphorus fertilizer at the end of its life as an adsorbent.

Assessment of biotechnological potential of phosphate solubilizing bacteria isolated from soils of Southern Kazakhstan

Phosphorus (P) is a vital plant nutrient, available to plant roots only in soluble forms that are in short supply in the soil. Adding phosphate- based fertilizers to increase agricultural yields is a widely used practice;however, the bio- availability of P remains low due to chemical transformations of P into insoluble forms. Thus, phosphate solubilizing bacteria (PSB) play an important role in reducing P deficiency in soil. The goal of this study was to assess biotechnological potential of phosphate-solubilizing bacterial strains. In this study, phosphate solubilizing microorganisms (PSM) were isolated from different soil samples of Southern regions of Kazakhstan. The biological activity of PSM was studied based on their effect on the growth of wheat seeds. The different taxonomic genera of these PSM were identified: Arthrobacter spp., Aureobacterium spp., Azotobacter spp., Bacterium spp., Baccillus spp. Finally, phosphate- solubilizing activity of isolated strains of PSM was assessed.

Effectiveness of 3,4-Dimethylpyrazole Phosphate as Nitrification Inhibitor in Soil as Influenced by Inhibitor Concentration,Application Form, and Soil Matric Potential

The effcacy of nitrification inhibitors depends on soil properties and environmental conditions.The nitrification inhibitor 3,4-dimethylpyrazole phosphate(DMPP) was investigated in a sandy loam and a loamy soil to study its effec-tiveness as inffuenced by inhibitor concentration,application form,and soil matric potential.DMPP was applied with concentrations up to 34.6 mg DMPP kg-1 soil as solution or as ammonium-sulfate/ammonium-nitrate granules formulated with DMPP.DMPP inhibited the oxidation of ammonium in both soils,but this effect was more pronounced in the sandy loam than in the loamy soil.When applied as solution,increasing DMPP concentrations up to 7 mg DMPP kg-1 soil had no inffuence on the inhibition.The effectiveness of DMPP formulated as fertilizer granules was superior to the liquid application of DMPP and NH4+,particularly in the loamy soil.Without DMPP,a decline in soil matric potential down to -600 kPa decreased nitrification in both soils,but this effect was more pronounced in the sandy loam than in the loamy soil.DMPP was most effective in the sandy loam particularly under conditions of higher soil moisture,i.e.,under conditions favorable for nitrate leaching.

Rice Glucose 6-Phosphate/Phosphate Translocator 1 is required for tapetum function and pollen development

In plants, non-green plastids in heterotrophic tissues are sites for starch and fatty acids biosynthesis,which are essential for plant development and reproduction. Distinct from chloroplasts, the metabolites for these processes in non-green plastids have to be imported through specific transporters. Glucose 6-Phosphate/Phosphate Translocator 1 is required for the uptake of cytosolic Glucose 6-Phosphate into non-green plastids. In Arabidopsis, GPT1 has been demonstrated to play essential roles in male, female gametophyte and embryo development. However, the roles of GPTs in other species are yet largely unknown. Here, we reported that rice OsGPT1 is indispensable for normal tapetal degeneration and pollen exine formation during anther and pollen development. OsGPT1 is localized in the plastid and distributed in the anther wall layers and late-stage pollen grains. Different from the gametic defects caused by mutation in At GPT1, disruption of OsGPT1 does not affect male and female gamete transmission as well as embryo development. On the contrary, osgpt1 mutant exhibits delayed tapetum degeneration,decreased Ubisch bodies formation and thinner pollen exine, leading to pollen abortion at the mature stage. Furthermore, the expression of several genes involved in tapetal programmed cell death(PCD)and sporopollenin formation is decreased in osgpt1. Our study suggests that OsGPT1 coordinates the development of anther sporophytic tissues and the male gametophyte by integrating carbohydrate and fatty acid metabolism in the plastid.