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Worldwide demand of phosphate fertilizer is met essentially from phosphatic rocks. India imports most of its requirements and produces a small portion through froth flotation of Precambrian stromatolitic rock phosphate. Increasing population and consequent increase in demand for food production necessitated investigation to utilize the large reserv...
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Context 1
... may improve further by changing the composition of the recipe. Details of feed mix, tempera- ture and times of retention at fusion temperature are given in Tables 2 and 3. The product FCMP was ground to 80% 100 μm (150 mesh) size to analyse citrate solubility of its pho- sphate content. Neutral ammonium citrate was used to determine the solubility. ...
Citations
... Low-grade PRs contain low P (<11% P) and a high level of impurities and consequently may remain unutilized for fertilizer production (Calle-Castaneda et al., 2018;Kumari and Phogat, 2008). However, they are believed to constitute approximately 40-50% of PR resources (Ranawat et al., 2009). ...
Phosphate fertilizers are produced from phosphate rock (PR), an indispensable and finite resource. To extend its life span, the mined PR needs to be processed into P fertilizers with minimum waste. The fertilizers need to supply P to plants at optimal levels and maximum efficacy. It is also imperative that the production of P fertilizers and their usage should not have a significant negative impact on the environment. Production and usage of currently manufactured and widely used phosphate fertilizers such as triple superphosphate and ammonium phosphates have stark limitations in all these respects. PR premixed with elemental sulfur (So) and Acidithiobacillus sp. bacterial culture (PR/So/Cult) or without the culture (PR/So) are environmentally friendly phosphate fertilizers. In this Chapter, using meta-analyses results from multiple trials conducted across countries we quantified the agronomic effectiveness of PR/So/Cult and PR/So on permanent pastures and seasonal crops. Strong evidence emerges that PR/So/Cult is agronomically a better alternative to chemically processed fertilizers for application to permanent pastures and short-term crops in a wide range of soil and climatic conditions. Considering the simplicity of the method, the fertilizer can be manufactured at remarkably low capital and operating costs. The conclusions support the need for a major change in phosphate fertilizer production moving towards biotechnology and away from chemical processing. A recently innovated biotechnology has the potential for large-scale production of PR/So/Cult.
... Fused magnesium phosphates are produced by heating mixtures of PR with olivine/serpentine to 1773-1873 K, and Rhenania phosphates are produced when a PR, soda ash, and silica mixture is heated between 1473 and 1573 K [11][12][13][14]. Additives used in fused magnesium phosphate production aid in collapsing the apatite crystal lattice by encouraging defluorination and forming a eutectic system that reduces the fusion temperature [14,15]. However, the process consumes a lot of water, which is used to quench the melt to stop recrystallization and fix the remaining fluorine in a vitreous phase [16][17][18]. ...
The lack of low-cost phosphorus fertilizers is a major limitation for food production on Zimbabwe’s many smallholdings. A thermally fused magnesium phosphate could be manufactured from the local Dorowa phosphate rock (PR) but would be expensive because of the high cost of required additives and energy. This paper investigates the phosphorus solubility of mixtures of igneous Dorowa PR with either recycled glass or magnesium silicates, before and after thermal alteration at sub-fusion temperatures. The thermal behavior and chemical transformation of Dorowa PR and various additives were investigated by thermo-gravimetric and differential scanning calorimetric analysis and X-ray powder diffraction. Thermal transformation of Dorowa PR + serpentine and Dorowa PR + dunite mixtures resulted in decomposition of calcite, kellyite, lizardite, and chrysotile present in the original mixtures and recrystallization of dehydroxylated metachrysotile to forsterite. The final products of air-cooled Dorowa PR + glass mixtures sintered at 1173 K contained ahrensite (Fe2(SiO4)), wollastonite (CaSiO3), quartz (SiO2), and hydroxy-fluorapatite. Compared to the unamended Dorowa PR, thermal alteration of Dorowa PR + glass mixtures at 1173 K led to a 62%, 73%, and 44% increase in citric soluble phosphorus when mixed at 1:2, 1:1, and 2:1 (Dorowa PR:glass), respectively. This increase in the citric soluble phosphorus content increases the agronomic value of Dorowa PR and is likely the result of substitution of PO3−4
in hydroxy-fluorapatite by SiO4−4
and or Mg2+/Na+ for Ca2+ and Fe2+.
... Consequently, K deficiencies become a problem because K decreases easily in soils due to crop uptake, run off, leaching and soil erosion . Direct application of rock phosphate (RP) and potassium (RK) materials may be agronomically more useful and environmentally more feasible than soluble P and K (Ranawat et al., 2009). Rock P and K materials are cheaper sources of P and K; however, most of them are not readily available to a plant because the minerals are released slowly and their use as fertilizer often causes insignificant yield increases of current crop (Zapata and Roy, 2004). ...
Two separate field experiments were conducted during 2013 and 2014 to study the effects of natural sources of phosphorus and potassium fertilizers as rock phosphate (RP) and feldspar (F) with or without biofertilizers comparing with chemical fertilizer (PK) on growth, yield and quality characteristics of roselle (Hibiscus sabdariffa L.) plant. The first experiment included phosphorus treatments (at different levels of rock phosphate; 150, 200 and 250 kg/fed) and the second one included potassium treatments (at different levels of feldspar; 250, 350 and 450 kg/fed), each comparing with recommended dose of chemical PK. The obtained results revealed that co-inoculation of PDB (Bacillus megaterium var. phosphaticum) and KDB (Bacillus mucilaginosus) in conjunction with direct application of rock phosphate at rates of 200 and 250 kg/fed and feldspar at rates of 350 and 450 kg/fed respectively, into the soil significantly increased the growth characteristics under the study (plant height, number of branches/plant, fresh and dry weight/plant,) along with yield (number of fruits/plant, fresh weight of fruit/plant, fresh and dry weight of sepals/plant, weight of seeds g/plant and weight of dry sepals kg/fed) comparing to chemical PK and other treatments. The highest growth and yield were obtained from plants treated with 200 kg/fed rock phosphate plus PDB in the first experiment and 350 kg/fed feldspar plus KDB in the second experiment. While PK treatment resulted in the highest acidity % and total anthocyanin content of dry sepals as compared to all the other treatments in the first and second seasons. Generally, the results suggest that the use of biofertilizer with rock phosphate or with feldspar are economical, environmental friendly and have potential to improve roselle yield and quality.
... FCMP is a type of vitreous phosphate fertilizer formed by melting phosphate rock with a fusing agent (containing magnesium and silicon minerals) at temperatures above 1400 °C, followed by rapid hardening with water. The P 2 O 5 content of the product is 12 -20 % (Ranawat et al., 2009). ...
Phosphate rocks are the commercial source used as raw material for manufacturing phosphoric acid, phosphate fertilizers and certain other chemicals. Phosphate rocks can be used directly in some applications, whereas beneficiation is required to upgrade the ore to more than 29% of P 2 O 5 when used as a raw material for the production of fertilizers, phosphoric acid and many other phosphate compounds. Phosphatic fertilizers are the most important end-product of phosphoric acid. Production of phosphoric acid is the first step in the manufacture of many phosphatic fertilizers. Phosphoric acid and phosphate compounds can be used directly in chemical industries or as a key ingredient in the production of many other chemicals required in detergents, animal feed, food, beverages, surface treatment (metal cleaning, coating), water treatment, dentistry, tooth pastes, fire extinguishers amongst many others. High purity phosphate compounds are also used in food and pharmaceutical production. Phosphorus as an element and some other phosphoric chemicals derived from phosphate rocks are used in pesticides, matches, fireworks and also in many military applications.
... In these instances, potassium fertilizer must be applied to ensure healthy plant growth. The direct application of rock phosphate (RP) and potassium (rock K) materials is more agronomically useful and even environmentally feasible than soluble P and K (Rajan et al. 1996;Ranawat et al. 2009). It is also considered as cheaper sources of P and K, but they are not easily available to plants because of its slow release of the mineral, and its use seems to be insignificant in present-day agriculture due to overemphasis on more yields at short time. ...
The K+ is not just the essential nutrient required to support optimal plant growth and yield, it is also an important signaling agent mediating a wide range of plant adaptive responses to abiotic and biotic stresses such as drought, salinity, oxidative stress, and apoptosis. The main source of K+ for plant is soil which is taken up by the plant roots through the epidermal and cortical cells and transported to the shoot and distributed to the leaves. Movement of K+ is facilitated by transport systems present in the cell membrane and the availability of which strongly determines crop yield. It is important to note that only a small percentage of the total K+ of the soil exists in a form available for plant uptake. The remainder is in complex with other elements and organic matter, making it unavailable and even intensive agricultural practices is adding to K+ deficiency in soil. It is already reported that large agricultural areas of world are deficient in K+ availability which is a major concern today. In this connection, efforts to understand the K+ uptake by plants and its solubilization from the K-bearing minerals such as waste muscovite, biotite, feldspars, orthoclase, illite, and mica have been undertaken. Recent investigations have shown that organic exudates of some microorganisms such as Pseudomonas spp., Burkholderia spp., Acidithiobacillus ferrooxidans, Bacillus mucilaginosus, B. edaphicus, B. megaterium, and Aspergillus spp., and even plant roots play a key role in releasing non-available K+ from the minerals. The list of rhizosphere microflora with potassium solubilization is increasing, and hence the present chapter discusses the mechanism of K+ solubilization and its role in signaling its uptake system in plants. Plant species effective in K+ uptake and K+-solubilizing microbial populations may be further key factors that control the K+ release from soil minerals.
... Consequently, K deficiencies become a problem because K decreases easily in soils due to crop uptake, runoff, leaching and soil erosion (). Direct application of rock phosphate (rock P) and potassium (rock K) materials may be agronomically more useful and environmentally more feasible than soluble P and K (Rajan et al., 1996; Ranawat et al., 2009). Rock P and K materials are cheaper sources of P and K; however, most of them are not readily available to a plant because the minerals are released slowly and their use as fertilizer often causes insignificant yield increases of current crop (Zapata and Roy, 2004 ). ...
... Consequently, K deficiencies become a problem because K decreases easily in soils due to crop uptake, runoff, leaching and soil erosion . Direct application of rock phosphate (rock P) and potassium (rock K) materials may be agronomically more useful and environmentally more feasible than soluble P and K (Rajan et al., 1996;Ranawat et al., 2009). Rock P and K materials are cheaper sources of P and K; however, most of them are not readily available to a plant because the minerals are released slowly and their use as fertilizer often causes insignificant yield increases of current crop (Zapata and Roy, 2004). ...
The present work evaluated the synergistic effects of soil fertilization with rock P and K materials and co-inoculation with P and K-dissolving bacteria [PDB (Bacillus megaterium var. phosphaticum) and KDB (Bacillus mucilaginosus and B. subtilis)] on the improvement of P and K uptake, P and K availability and growth of maize plant grown under limited P and K soil conditions (calcareous soil). The experiment was establishment with eight treatments: without rock P and K materials or bacteria inoculation (control), rock P (RP), rock K (RK), RP + PDB, RK + KDB and R(P + K)+(P + K)DB. Under the same conditions of this study, co-inoculation of PDB and KDB in conjunction with direct application of rock P and K materials (R(P + K)) into the soil increased P and K availability and uptake, and the plant growth (shoot and root growth) of maize plants grown on P and K limited soils.
Phosphorus is an irreplaceable nutrient for crop planting, and the water-soluble phosphate radical can readily dissolve in water and combine with the metals in soils resulting in deactivation. The transform of water-soluble phosphate to citric-soluble phosphate is critical to reduce immobilization and improve the effectiveness of fertilizer. In the current work, Mg–Al-layered double hydroxide (LDH) doped with phosphate radical for preparation of slow-release phosphate fertilizers was conducted. The effects of LDH dosage and pH on the phosphate transformation were systematically studied. Results demonstrated that LDH could successfully help the water-soluble phosphorus convert into citric-soluble phosphate. Under the weak acid condition, the maximum doping capacity of P2O5 by LDH was 320.5 mg/g. After doping, about two-thirds phosphate of the sample is citrate-soluble phosphate which has a slow-release function. XRD, FTIR, and TG analyses showed that the adsorption of phosphate by LDH was a combination of dissolution reprecipitation and interlayer intercalation.KeywordsMg–Al–LDHPhosphate radicalPhosphorus formSlow-release phosphate fertilizers
This paper presents the most important issues relating to the influence of mineral fertilizers on both the natural environment and human and animal health. The physiological, environmental and economic impact of fertilizer production and application, resulted from a low assimilation of mineral components by crops, has been described. The research on the development and production of a large and diverse group of materials with slow-release properties that can increase the effectiveness of nutrient uptake, alleviate the negative influence of fertilizers on the environment and reduce labor and energy consumption associated with the use of conventional fertilizers, has been reviewed.
Bacteria capable of potassium-releasing are spread among phylogenetically diverse groups. The purpose of this work was to study the microbial diversity and potassium-releasing capacity of potassium-releasing strains isolated from four rhizosphere soil samples of tobacco from Luzhou, Sichuan Province, China. The density of potassium-releasing bacteria in the S soil sample was significantly higher than in others. Potassium-releasing bacteria isolated from four soils were grouped into 18 strains according to ARDRA. One colony was picked to culture and sequencing from each of the 18 strains to construct the phylogenetic tree, and the tree obtained from the sequences revealed four major branches exhibiting highest identity to the following genera: (i) Bacillus, (ii) Enterobacter, (iii) Pseudomonas and (iv) Providence. Majority of the strains with high potassium-releasing efficiency belong to Bacillus, and JK01 [Bacillus mo/avensis) possesses the highest capability of potassium-releasing (95.01% higher than the control), it has greater potential to serve as plant growth promoting rhizobacteria.
