The agronomic effectiveness of reactive phosphate rocks 2. Effect of phosphate rock reactivity

1997 ◽  
Vol 37 (8) ◽  
pp. 937 ◽  
Author(s):  
R. J. Gilkes ◽  
M. D. A. Bolland
Keyword(s):  
Formic Acid ◽  
Phosphate Rock ◽  
Chemical Reactivity ◽  
Water Soluble ◽  
Annual Rainfall ◽  
X Ray Diffraction ◽  
Agronomic Effectiveness ◽  
P Content ◽  
The Relationship ◽  
Phosphate Rock Reactivity

Summary. The chemical reactivity of apatite phosphate rock (PR) from Sechura (Bayovar), North Carolina, Egypt (Hamrawein), Morocco (Khouribja) and Queensland (Duchess), was estimated using the following methods (indices): percentage of the phosphorus (P) present in the PR that is soluble in one extraction with 2% citric acid and 2% formic acid, and variation in crystal chemistry determined using X-ray diffraction to measure the length of the unit cell a dimension. The indices were related to the agronomic effectiveness of the PRs for pasture using percentage of the maximum (relative) yields for PR and superphosphate. At most sites there was a statistically significant trend for the agronomic effectiveness of the PRs to increase with increasing reactivity of the PRs as assessed by the 3 indices. However, this was not the case for sites where: (i) leaching of water-soluble P from freshly-applied superphosphate occurs in wet years; and (ii) the agronomic effectiveness using SV 50 values of all the PRs was uniformly low so that no differences between the PRs could be detected. The relationship between the agronomic effectiveness (SV50) of PR and chemical reactivity of the PR were generally different each year and in most cases this variability was related to the variation in total annual rainfall. From this study it is concluded that PRs in which greater than 65–70% of their total P content is soluble in 2% formic acid are likely to be highly reactive and therefore agronomically effective P fertilisers for direct application to appropriate soils in suitable environments.

The agronomic effectiveness of reactive phosphate rocks 1. Effect of the pasture environment

1997 ◽  
Vol 37 (8) ◽  
pp. 921 ◽  
Author(s):  
P. W. G Sale ◽  
R. J. Gilkes ◽  
M. D. A. Bolland ◽  
P. G. Simpson ◽  
D. C. Lewis ◽  
...  
Keyword(s):  
North Carolina ◽  
Phosphate Rock ◽  
Surface Soil ◽  
Annual Rainfall ◽  
Triple Superphosphate ◽  
Agronomic Effectiveness ◽  
P Sorption ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
Very High

Summary. The agronomic effectiveness of directly applied North Carolina reactive phosphate rock was determined for 4 years from annual dry matter responses at 26 permanent pasture sites across Australia as part of the National Reactive Phosphate Rock Project. Fertiliser comparisons were based on the substitution value of North Carolina reactive phosphate rock for triple superphosphate (the SV50). The SV50 was calculated from fitted response curves for both fertilisers at the 50% of maximum yield response level of triple superphosphate. The reactive phosphate rock was judged to be as effective as triple superphosphate in the 1st year (and every year thereafter) at 4 sites (SV50 >0.9), and was as effective by the 4th year at 5 sites. At another 9 sites the reactive phosphate rock was only moderately effective with SV50 values between 0.5 and 0.8 in the 4th year, and at the final 8 sites it performed poorly with the 4th year SV50 being less than 0.5. Pasture environments where the reactive phosphate rock was effective in the 1st year were: (i) those on sandy, humic or peaty podsols with an annual rainfall in excess of 850 mm; (ii) those on soils that experienced prolonged winter inundation and lateral surface flow; and (iii) tropical grass pastures in very high rainfall areas (>2300 mm) on the wet tropical coast on North Queensland. The highly reactive North Carolina phosphate rock became effective by the 4th year at sites in southern Australia where annual rainfall exceeded 700 mm, and where the surface soil was acidic [pH (CaCl2) <5.0] and not excessively sandy (sand fraction in the A1 horizon <67%) but had some phosphorus (P) sorption capacity. Sites that were unsuitable for reactive phosphate rock use in the medium term (up to 4 years at least) were on very high P-sorbing krasnozem soils or high P-sorbing lateritic or red earth soils supporting subterranean-clover-dominant pasture, or on lower rainfall (< 600 mm) pastures growing on soils with a sandy A1 horizon (sand component >84%). No single environmental feature adequately predicted reactive phosphate rock performance although the surface pH of the soil was most closely correlated with the year-4 SV50 (r = 0.67). Multiple linear regression analysis found that available soil P (0–10 cm) and the P sorption class of the surface soil (0–2 cm), together with annual rainfall and a measure of the surface soil"s ability to retain moisture, could explain about two-thirds of the variance in the year-4 SV50 . The results from this Project indicate that there are a number of specific pasture environments in the higher rainfall regions of Australia where North Carolina reactive phosphate rock can be considered as an effective substitute P fertiliser for improved pasture.

An appraisal of the National Reactive Phosphate Rock Project

1997 ◽  
Vol 37 (8) ◽  
pp. 1085
Author(s):  
D. J. Reuter
Keyword(s):  
Expert System ◽  
Phosphate Rock ◽  
Field Experiments ◽  
Water Soluble ◽  
Annual Rainfall ◽  
Yield Response ◽  
Triple Superphosphate ◽  
Reactive Phosphate ◽  
Independent Field ◽  
Reactive Phosphate Rock

Summary. An expert system has been developed, using the results from the National Reactive Phosphate Rock Project, to determine whether reactive phosphate rock is likely to be an effective substitute for water-soluble superphosphate fertiliser for a given pasture environment. The evaluation is made from site information [annual rainfall, pasture composition and the likelihood of phosphorus (P) leaching], and soil information (pH, Colwell P, soil colour and field texture). The expert system can determine the effectiveness of both highly reactive and moderately reactive phosphate rocks. Observed substitution values of triple superphosphate for the highly reactive North Carolina phosphate rock (ratio of the respective P levels required to produce 50% of the maximum observed yield response to triple superphosphate) were closely related to values predicted by the expert system (r = 0.92); the relationship between observed and predicted substitution values of single superphosphate for the moderately reactive Hemrawein phosphate rock was also close (r= 0.86). The expert system gives one of 4 different recommendations for reactive phosphate rock based on the magnitude of the predicted substitution values. These are ‘immediately effective’, ‘effective in the medium term’, ‘marginally effective’, and ‘not effective’. The system was validated using the results from independent field experiments that provided measures of the effectiveness of reactive phosphate rock at different pasture sites.

Rietveld refinement of YbCoO3 prepared from aqueous solution-gel precursor

2007 ◽  
Vol 22 (1) ◽  
pp. 35-39 ◽  
Author(s):  
L. Ben Farhat ◽  
R. Ben Hassen ◽  
L. Dammak
Keyword(s):  
Cell Parameter ◽  
Rietveld Method ◽  
Polycrystalline Sample ◽  
Water Soluble ◽  
Complex Method ◽  
X Ray Diffraction ◽  
Soluble Complex ◽  
X Ray ◽  
The Relationship ◽  
Water Soluble Complex

A polycrystalline sample of YbCoO3 was prepared using a water-soluble complex method at relatively low temperatures. Common chelating ligands such as citric acid were employed for the synthesis of complex-based precursors, followed by thermal decomposition of the precursors at high temperatures. X-ray diffraction data were collected and the crystal structure was refined by the Rietveld method. The structure of YbCoO3 can be described as a sesquioxide C-M2O3-like structure with space group Ia-3 and unit-cell parameter a=10.4470 (2). The Yb3+ and the Co3+ cations are found to preferentially occupy the two nonequivalent 8d and 24d sites, respectively. The two independent atoms Yb/Co have octahedral coordination; however, the degrees of distortion of their coordination polyhedron are different. The relationship between the title compound and the orthorhombic Perovskite structure of YbCoO3 reported in the literature is established.

Pasture environments in Australia where reactive phosphate rock will be an effective phosphate fertiliser

1997 ◽  
Vol 37 (8) ◽  
pp. 1051 ◽  
Author(s):  
P. W. G. Sale ◽  
A. Brown ◽  
G. Maclaren ◽  
P. K. Derbyshire ◽  
S. M. Veitch
Keyword(s):  
Soil Properties ◽  
Phosphate Rock ◽  
Water Soluble ◽  
Annual Rainfall ◽  
High Rainfall ◽  
Water Soluble P ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
Suitability Maps ◽  
Soluble P

Summary. Maps are constructed using Geographic Information Systems (GIS) computer technology to identify privately held land in the high rainfall zones of temperate and tropical Australia where highly reactive phosphate rocks (RPRs) are likely to be effective phosphorus (P) fertilisers for permanent pasture. Australia-wide RPR suitability maps were based on annual rainfall, soil pH and the P sorption capacity of the soil. The digitised soil map from the Atlas of Australian Soils and the soil profile acidity map derived from the Atlas, were used to identify land areas with suitable soil properties. The coarse scale of the Atlas, which has only the 1 dominant soil for each 100 ha minimum landscape unit, limits the precision in identifying specific land types. Reactive phosphate rock suitability maps for pasture land in Victoria were also developed using smaller land units and state-wide digitised soil maps for surface pH and surface texture. The GIS maps indicated that there are about 26.5 × 106 ha of land in the high rainfall pastoral zone of Australia that have sufficient annual rainfall and appropriate soil properties for RPR to become effective by the 4th year after changing from annual water-soluble P fertiliser to RPR fertiliser applications. Additional land with a lower rainfall might also be suitable if the soil surface is not excessively sandy. The area of high rainfall pasture land where RPR is likely to be as effective as water-soluble P fertiliser in the first year of application is around 3 × 106 ha. The major portion of this land is in North Queensland, with smaller areas in southern Victoria, in far north-west Tasmania and in the far south-west of Western Australia. More detailed GIS maps for Victoria indicate that RPRs would become as effective as water-soluble P fertiliser by the 4th year on more than 70% of private land where annual rainfall exceeds 700 mm.

Building an expert system to advise on the use of reactive phosphate rock on Australian pastures

1997 ◽  
Vol 37 (8) ◽  
pp. 1077 ◽  
Author(s):  
P. Gillard ◽  
P. W. G. Sale ◽  
S. B. Tennakoon
Keyword(s):  
Expert System ◽  
Phosphate Rock ◽  
Field Experiments ◽  
Water Soluble ◽  
Annual Rainfall ◽  
Yield Response ◽  
Triple Superphosphate ◽  
Reactive Phosphate ◽  
Independent Field ◽  
Reactive Phosphate Rock

Summary. An expert system has been developed, using the results from the National Reactive Phosphate Rock Project, to determine whether reactive phosphate rock is likely to be an effective substitute for water-soluble superphosphate fertiliser for a given pasture environment. The evaluation is made from site information [annual rainfall, pasture composition and the likelihood of phosphorus (P) leaching], and soil information (pH, Colwell P, soil colour and field texture). The expert system can determine the effectiveness of both highly reactive and moderately reactive phosphate rocks. Observed substitution values of triple superphosphate for the highly reactive North Carolina phosphate rock (ratio of the respective P levels required to produce 50% of the maximum observed yield response to triple superphosphate) were closely related to values predicted by the expert system (r = 0.92); the relationship between observed and predicted substitution values of single superphosphate for the moderately reactive Hemrawein phosphate rock was also close (r= 0.86). The expert system gives one of 4 different recommendations for reactive phosphate rock based on the magnitude of the predicted substitution values. These are ‘immediately effective’, ‘effective in the medium term’, ‘marginally effective’, and ‘not effective’. The system was validated using the results from independent field experiments that provided measures of the effectiveness of reactive phosphate rock at different pasture sites.

Assessment of soil phosphorus tests for situations in Australia where reactive phosphate rock and water-soluble phosphorus fertilisers are used

1997 ◽  
Vol 37 (8) ◽  
pp. 1027 ◽  
Author(s):  
P. G. Simpson ◽  
M. J. McLaughlin ◽  
A. J. Weatherley ◽  
P. W. G. Sale ◽  
V. Hoy ◽  
...  
Keyword(s):  
Phosphate Rock ◽  
Soil Phosphorus ◽  
Subterranean Clover ◽  
Soil Test ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
P Content ◽  
Soil Test P ◽  
The Relationship ◽  
Bray 1

Summary. A selection of commonly used soil phosphorus (P) tests, which included anion and cation exchange resin membranes, were compared in a glasshouse experiment using subterranean clover, and evaluated in the field at 19 sites from the National Reactive Phosphate Rock Project in 1993 and at 6 sites in 1995. The ability of the soil P tests to predict plant response was used to evaluate the tests. In the glasshouse experiment the resin test was less effective than the Bray 1 and Colwell tests in its ability to assess the level of plant-available P from the different fertiliser treatments. Seventy-one percent of the variation in total P content of the subterranean clover shoots was explained by resin-extractable P values, whereas the Colwell procedure accounted for 81% and the Bray 1 procedure accounted for 78%. Water and CaCl2 extracts were poor predictors of P content. In the field experiments all tests evaluated performed poorly in describing the relationship between soil test P and the level of P applied and relative yield and soil test P over a wide range of soil types and environments. The Bray 1 procedure performed best but the relationship was poor.

scholarly journals Temperature Effects on Properties of Rice Husk Biochar and Calcinated Burkina Phosphate Rock

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 432
Author(s):  
Vincent K. Avornyo ◽  
Andrew Manu ◽  
David A. Laird ◽  
Michael L. Thompson
Keyword(s):  
Formic Acid ◽  
Rice Husk ◽  
Phosphate Rock ◽  
Pyrolysis Temperature ◽  
Sub Saharan Africa ◽  
Amorphous Sio2 ◽  
Extractable P ◽  
P Content ◽  
Sub Saharan ◽  
Rice Husk Biochar

Rice husk biochar (RHB) and phosphate rock (PR) are locally accessible resources that poor farmers in Sub-Saharan Africa (SSA) can utilize to increase rice productivity. However, biochars are variable depending on feedstock, pyrolysis temperature, and duration. Phosphate rocks from SSA are of low solubility. The goal of this study was to determine whether pyrolysis of rice husk (RH), calcination of PR, and the calcination/pyrolysis of a RHB-PR mixture at 300 °C, 500 °C, and 700 °C can increase formic acid (FA)- extractable phosphorous (P). The properties of these RHBs were compared to the properties of RHB produced through a simple farmer-friendly pyrolysis technique termed “Kun-tan”. Properties of calcinated PR were also compared to the raw PR. Quartz formed from amorphous SiO2 during RH pyrolysis and was the dominant mineral phase in the biochars, irrespective of the pyrolysis temperature. Formic acid-extractable P content, pH, and ash content of the biochars increased with increasing pyrolysis temperature. At 700 °C, FA-extractable P content of the RHB was 219% more than the feedstock. Hydroxyapatite and quartz were the dominant minerals in the PR irrespective of calcination temperature, indicating that hydroxyapatite and quartz were stable to at least 700 °C. Rather, calcination decreased the FA-extractable P content of the PR.

National Reactive Phosphate Rock Project —aims, experimental approach and site characteristics

1997 ◽  
Vol 37 (8) ◽  
pp. 885 ◽  
Author(s):  
M. J. McLaughlin ◽  
N. K. Fleming ◽  
P. G. Simpson ◽  
M. D. A. Bolland ◽  
R. J. Gilkes ◽  
...  
Keyword(s):  
North Carolina ◽  
Formic Acid ◽  
Phosphate Rock ◽  
Soil Phosphorus ◽  
Triple Superphosphate ◽  
Phosphate Rocks ◽  
Agronomic Effectiveness ◽  
North Carolina Phosphate Rock ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock

Summary. Field-based cutting trials, which formed part of the National Reactive Phosphate Rock Project, were established across Australia in a range of environments to evaluate the agronomic effectiveness of 5 phosphate rocks, and 1 partially acidulated phosphate rock, relative to either single superphosphate or triple superphosphate. The phosphate rocks differed in reactivity. Sechura (Bayovar) and North Carolina phosphate rocks were highly reactive (>70% solubility in 2% formic acid), whilst Khouribja (Moroccan) and Hamrawein (Egypt) phosphate rock were moderately reactive. Duchess phosphate rock from Queensland was relatively unreactive (<45% solubility in 2% formic acid). Phosphate rock effectiveness was assessed by measuring pasture production over a range of phosphorus levels, and by monitoring bicarbonate-soluble phosphorus extracted from soil samples collected before the start of each growing season. Other treatments included single large applications of triple superphosphate, partially acidulated phosphate rock and North Carolina phosphate rock applied at 2 rates, and the application of monocalcium phosphate and North Carolina phosphate rock sources without sulfur to evaluate the importance of sulfur in the potential use of phosphate rock fertilisers at each site. A broad range of environments were represented over the 30 sites which were based on pastures using annual and/or perennial legumes and perennial grasses. Rainfall across the network of sites ranged from 560 to 4320 mm, soil pH (CaCl2) from 4.0 to 5.1, and Colwell-extractable phosphorus ranged from 3 to 47 µg/g before fertiliser application. Two core experiments were established at each site. The first measured the effects of phosphate rock reactivity on agronomic effectiveness, while the second measured the effects of the degree of water solubility of the phosphorus source on agronomic effectiveness. The National Reactive Phosphate Rock Project trials gave the opportunity to confirm the suitability of accepted procedures to model fertiliser response and to develop new approaches for comparing different fertiliser responses. The Project also provided the framework for subsidiary studies such as the effect of fertiliser source on soil phosphorus extractability, cadmium and fluorine concentrations in herbage, evaluation of soil phosphorus tests, and the influence of particle size on phosphate rock effectiveness. The National Reactive Phosphate Rock Project presents a valuable model for a large, Australia-wide, collaborative team approach to an important agricultural issue. The use of standard and consistent experimental methodologies at every site ensured that maximum benefit was obtained from data generated. The aims, rationale and methods used for the experiments across the network are presented and discussed.

scholarly journals Irregular Electrodeposition of Cu-Sn Alloy Coatings in [EMIM]Cl Outside the Glove Box with Large Layer Thickness

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 310
Author(s):  
Lars Lehmann ◽  
Dominik Höhlich ◽  
Thomas Mehner ◽  
Thomas Lampke
Keyword(s):  
Layer Thickness ◽  
Alloy System ◽  
Liquid Solution ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
X Ray ◽  
Argon Stream ◽  
Ionic Liquid Solution ◽  
The Relationship ◽  
Layer Composition

Thick Cu−Sn alloy layers were produced in an [EMIM]Cl ionic-liquid solution from CuCl2 and SnCl2 in different ratios. All work, including the electrodeposition, took place outside the glovebox with a continuous argon stream over the electrolyte at 95 °C. The layer composition and layer thickness can be adjusted by the variation of the metal-salts content in the electrolyte. A layer with a thickness of up to 15 µm and a copper content of up to ωCu = 0.86 was obtained. The phase composition was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). Furthermore, it was found that the relationship between the alloy composition and the concentration of the ions in the electrolyte is described as an irregular alloy system as according to Brenner. Brenner described such systems only for aqueous electrolytes containing complexing agents such as cyanide. In this work, it was confirmed that irregular alloy depositions also occur in [EMIM]Cl.

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