A re-evaluation of the effectivenes of calcined Christmas Island C-grade rock phosphate

1979 ◽  
Vol 19 (100) ◽  
pp. 605 ◽  
Author(s):  
B Palmer ◽  
MDA Bolland ◽  
RJ Gilkes
Keyword(s):  
Rock Phosphate ◽  
Relative Effectiveness ◽  
Maximum Yield ◽  
Calcination Temperatures ◽  
Christmas Island ◽  
Grade Rock

The influence of calcination temperatures up to 1050�C on the effectiveness of Christmas Island C-grade ore was determined in glasshouse trials with wheat. All calcines were capable of supporting the same maximum yield. Maximum effectiveness, equivalent to one-third that of superphosphate, occurred for calcination temperatures between 450�C and 600�C. Re-evaluation of the results of other workers indicated that a similar value for relative effectiveness applies to their work on a variety of species.

The response of a birdwood grass - Townsville lucerne pasture to phosphate fertilizers at Katherine, N.T

1965 ◽  
Vol 5 (17) ◽  
pp. 120 ◽  
Author(s):  
MJT Norman
Keyword(s):  
Dry Matter ◽  
Rock Phosphate ◽  
Maximum Yield ◽  
Experimental Period ◽  
Phosphate Fertilizers ◽  
Virgin Land ◽  
Christmas Island ◽  
Nitrogen Yields ◽  
Forage Yields

In an experiment at Katherine, N.T., the response of birdwood grass-Townsville lucerne (Cenchrus setigerus Vahl and Stylosanthes hurnilis H.B.K.) pasture sown on virgin land to levels of superphosphate and Christmas Island rock phosphate dust and to levels of superphosphate subsequently applied annually for three years was measured. There were no significant interactions between initial and annual applications. Initial applications of 2 and 4 cwt an acre superphosphate both gave higher forage yields of dry matter and nitrogen than 2 and 4 cwt an acre rock phosphate over the experimental period. Phosphorus yield of forage was a function of rate rather than of type of fertilizer. Annual superphosphate applications up to 1 cwt an acre increased the dry matter and nitrogen yields of the grass, but not those of the legume, and increased the phosphorus yield of both. The higher proportion of grass at high superphosphate levels was interpreted as a difference in responsiveness of the two species. A regime of 2 cwt an acre superphosphate initially and 1/2 cwt an acre annually produced 90 per cent of what was considered to be the maximum yield.

Calcined Christmas Island C-grade rock phosphate fertilizers: Mineralogical properties, reversion and assessment by chemical extraction

Soil Research ◽  
1979 ◽  
Vol 17 (3) ◽  
pp. 467 ◽  
Author(s):  
RJ Gilkes ◽  
B Palmer
Keyword(s):  
Rock Phosphate ◽  
Chemical Properties ◽  
Ammonium Citrate ◽  
Chemical Extraction ◽  
Phosphate Fertilizers ◽  
Christmas Island ◽  
Phosphorus Fertilizers ◽  
Different Temperatures ◽  
Grade Rock ◽  
And Chemical Properties

Calcination of Christmas Island C-grade ore at temperatures up to 1050�C produces phosphorus fertilizers that differ greatly in effectiveness as determined by citrate extraction and plant growth. Maximum effectiveness is obtained by calcination at temperatures between 500� and 650�C, and is best predicted by extractions of between 1 and 3 h duration in neutral ammonium citrate. Alkaline ammonium citrate and citric acid are poorer indicators of phosphorus availability. The mineralogical and chemical properties of the calcines may be used to explain variations in amounts of citrate soluble phosphorus for different temperatures of calcination. Incubation of moist 500�C calcined C-grade ore induces recrystallization (i.e. reversion) of some crandallite, resulting in a decrease in the solubility of phosphorus in neutral ammonium citrate and its availability to plants.

The relative value of water-soluble and ammonium-citrate-soluble phosphorus for wheat production

1982 ◽  
Vol 98 (2) ◽  
pp. 467-470 ◽  
Author(s):  
B. Palmer ◽  
R. S. Jessop
Keyword(s):  
Rock Phosphate ◽  
Water Soluble ◽  
Ammonium Citrate ◽  
Lower Grade ◽  
Wheat Production ◽  
Christmas Island ◽  
The Pacific ◽  
Relative Value ◽  
The Pacific Ocean ◽  
Grade Rock

Wheat production in Australia relies heavily on superphosphate to maintain maximum grain yields. The current rock-phosphate supplies for superphosphate manufacture are derived from Nauru and Christmas Island in the Pacific Ocean; these supplies are anticipated to last only for the next 10–20 years. The supplies of ‘A’ grade ore (apatite) which can be used directly for superphosphate production are greatly overshadowed by large amounts of lower grade rock phosphate which is high in total phosphate but low in apatite. This material is termed ‘C’ grade rock and, to date, it has found little use in Australian agriculture.

Calcined Christmas Island C-grade rock phosphate as a fertilizer

1975 ◽  
Vol 15 (74) ◽  
pp. 419 ◽  
Author(s):  
DN Wright
Keyword(s):  
Rock Phosphate ◽  
Initial Response ◽  
High Rate ◽  
Fine Material ◽  
Christmas Island ◽  
Residual Response ◽  
Yield Responses ◽  
Grade Rock ◽  
Pasture Plants ◽  
Better Than

A series of four pot experiments and one field experiment was conducted on two soils in northern Tasmania to compare calcined Christmas Island C-grade rock phosphate (CIP) with superphosphate as a source of phosphorus for pasture plants. On an acid, loamy sand CIP alone was better than superphosphate alone for the establishment of pasture plants. The initial response to CIP was best where a high rate of fine material was mixed into the surface soil. The residual response from the coarser CIP was greater than from the fine material. Yield responses from CIP plus ground limestone were lower than from CIP alone, particularly from the coarser grade of CIP. On the other soil, a krasnozem, CIP was inferior to superphosphate as a source of phosphorus.

Residual effectiveness of superphosphate is greater than that of rock phosphate fertilisers for lateritic soils in south-western Australia

1988 ◽  
Vol 28 (1) ◽  
pp. 83 ◽  
Author(s):  
MDA Bolland ◽  
AJ Weatherley ◽  
RJ Gilkes
Keyword(s):  
Western Australia ◽  
Rock Phosphate ◽  
Phosphorus Content ◽  
Maximum Yield ◽  
Subterranean Clover ◽  
Triple Superphosphate ◽  
Rock Phosphates ◽  
Lateritic Soils ◽  
Climatic Regions ◽  
Christmas Island

The residual values of granular reactive rock phosphate (highly carbonate-substituted apatite from North Carolina, USA.), partially powdered low-reactive Queensland rock phosphate (low carbonate-substituted apatite from the Duchess deposit), and granular triple superphosphate were measured in 3 experiments on different lateritic soils in different climatic regions of south-western Australia (Gibson, South Bodallin, West Dale). Finely powdered calcined crandallite-millisite rock phosphate from Christmas Island (Calciphos) was included in one of the experiments. The fertilisers were applied once only in May 1984 and their residual value measured over 3 years (1984-1986) using yield and phosphorus content of the following species each year: experiment 1 (Gibson), barley in years 1 and 2 and oats in the third year; experiment 2 (South Bodallin), triticale in all 3 years; experiment 3 (West Dale), subterranean clover in years I and 2 followed by oats in year 3. Relative to triple superphosphate (TSP) applied each year, the effectiveness of superphosphate in year 1 (year of application) in the experiment at Gibson decreased by about 40% between years 1 and 2, and by a further 5% between years 2 and 3. The corresponding values for the experiment at South Bodallin were 75% and 5%, and at West Dale 50% and 25%. All rock phosphates were much less effective than TSP in year 1, being 5-30% as effective as TSP. Effectiveness of rock phosphates remained low over the 3 years, being 5-20% as effective as newly applied TSP. Although the effectiveness of TSP decreased, it continued to be 50% as effective as newly applied TSP after 3 years. Residual TSP and both freshly applied and residual rock phosphates did not support the same maximum yield as freshly applied TSP despite well defined yield plateaux being obtained in each case. At each harvest, the relationship between yield and phosphorus content of plants was similar for all fertilisers so that the smaller maximum DM and grain yield and reduced effectiveness of the rock phosphates were largely due to less phosphorus being taken up by plants.

A ceramic composite derived from high-grade rock phosphate as a substitution for human bone

2019 ◽  
Vol 34 (12) ◽  
pp. 743-750
Author(s):  
Kalinga Hapuhinna ◽  
Rajitha Deshapriya Gunaratne ◽  
Jagath Pitawala
Keyword(s):  
Ceramic Composite ◽  
Rock Phosphate ◽  
Human Bone ◽  
High Grade ◽  
Grade Rock ◽  
High Grade Rock
Sign in / Sign up

Export Citation Format

Share Document