The response of peanuts to phosphate fertilizers at Katherine, N.T

1965 ◽  
Vol 5 (19) ◽  
pp. 470 ◽  
Author(s):  
LJ Phillips ◽  
MJT Norman
Keyword(s):  
Rock Phosphate ◽  
Early Growth ◽  
Phosphate Fertilizers ◽  
The Third ◽  
Virgin Land ◽  
Christmas Island ◽  
Equal Effectiveness

A four-year experiment on the response of successive crops of peanuts to rates of superphosphate and rock phosphate as initial broadcast applications on virgin land and to rates of annual banded superphosphate was carried out at Katherine, N.T., between 1960 and 1964. By the third year of cropping, with no annual superphosphate, the yield from 4 cwt an acre Nauru or Christmas Island rock phosphate applied initially was slightly greater than that from 4 cwt an acre superphosphate and substantially greater than that from 2 cwt an acre superphosphate. Nauru and Christmas Island rock phosphate were of approximately equal effectiveness. No significant responses were obtained to gypsum in the presence of Christmas Island rock phosphate. Peanuts responded to annual banded applications of superphosphate up to 1 cwt an acre in spite of heavy initial broadcast applications of phosphate. The banded superphosphate was of particular benefit in the establishment and early growth of the crop.

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.

scholarly journals Looming Scarcity of Phosphate Rock and Intensification of Soil Phosphorus Research

2015 ◽  
Vol 39 (3) ◽  
pp. 637-642 ◽  
Author(s):  
Philippe C. Baveye
Keyword(s):  
Phosphate Rock ◽  
Rock Phosphate ◽  
Soil Phosphorus ◽  
Agricultural Practices ◽  
Phosphate Fertilizers ◽  
Soil P ◽  
The Past ◽  
Essential Resource ◽  
The Moment ◽  
Short Essay

In recent years, many researchers have claimed that world reserves of rock phosphate were getting depleted at an alarming rate, putting us on the path to scarcity of that essential resource within the next few decades. Others have claimed that such alarmist forecasts were frequent in the past and have always been proven unfounded, making it likely that the same will be true in the future. Both viewpoints are directly relevant to the level of funding devoted to research on the use of phosphate fertilizers. In this short essay, it is argued that information about future reserves of P or any other resource are impossible to predict, and therefore that the threat of a possible depletion of P reserves should not be used as a key motivation for an intensification of research on soil P. However, there are other, more compelling reasons, both geopolitical and environmental, to urgently step up our collective efforts to devise agricultural practices that make better use of P than is the case at the moment.

Evaluation of phosphate fertilizers: II. Residual value of nitrophosphates, Gafsa rock phosphate, basic slag and potassium metaphosphate for potatoes, barley and swedes grown in rotation, with special reference to changes in soil phosphorus status

1968 ◽  
Vol 70 (2) ◽  
pp. 139-156 ◽  
Author(s):  
G. E. G. Mattingly
Keyword(s):  
Rock Phosphate ◽  
Crop Yields ◽  
Soil Analysis ◽  
Soil Phosphorus ◽  
P Uptake ◽  
Barley Grain ◽  
Yield Response ◽  
Residual Value ◽  
Basic Slag ◽  
Phosphate Fertilizers

SUMMARYThe residual value of three nitrophosphates, potassium metaphosphate, basic slag and rock phosphate was compared with that of superphosphate in two experiments with potatoes, barley and swedes grown in rotation. The residual value of the fertilizers was also compared with that of (a) six cumulative annual dressings of superphosphate supplying either one-half or the same total amounts of phosphate and (b) single fresh applications of superphosphate applied once in each rotation. Yields and phosphorus uptakes are discussed in relation to the amounts of soil phosphate soluble in 0·5 M-NaHCO3.In the first rotation residues of rock phosphate produced about 1 ton/acre less potato tubers than residues of other fertilizers and cumulative annual applications of superphosphate produced 0·6–0·9 tons/acre less tubers than all residues except rock phosphate. In the second rotation residues of fertilizers increased tuber yields less than cumulative dressings of superphosphate. Over two rotations mean yields from residues and from cumulative dressings were the same. Mean yields of barley over two rotations were 1–3 cwt/acre greater from residues than from cumulative annual dressings; the residual value of the different phosphates was the same. For swedes residues from the alternative phosphates, including basic slag and rock phosphate, were equivalent to those from superphosphate and gave the same mean yields as six cumulative dressings of superphosphate broadcast at planting.Average residual values of alternative phosphate fertilizers, calculated from (a) yield response, (b) P uptake, and (c) soil analysis were: superphosphate, 100; nitrophosphates, 100–102; potassium metaphosphate, 95; basic slag, 94; Gafsa rock phosphate, 92. Mean percentage ‘fresh’ superphosphate equivalents of residues from all fertilizers were 17 and 26% after the first rotation and 11 and 15% after the second rotation for potatoes and swedes respectively.The percentage of the total variance in crop yields accounted for by linear regression on NaHCO3-soluble P ranged from 38 to 70% for potatoes, 9 to 28% for barley grain and 42 to 92% for swedes. Mean yields of the crops increased by 0·24 ± 0·037 tons/acre (potatoes), 0·22 ± 0·08 cwt/acre (barley) and 1·16 ±0·148 tons/acre (swedes) for each ppm NaHCO3-soluble phosphorus in the soil at harvest.

scholarly journals Field experiments on phosphate fertilizers: A joint investigation

1956 ◽  
Vol 48 (1) ◽  
pp. 74-103 ◽  
Author(s):  
G. W. Cooke
Keyword(s):  
Rock Phosphate ◽  
Field Experiments ◽  
Acid Soils ◽  
Water Soluble ◽  
Dicalcium Phosphate ◽  
Low Grade ◽  
Basic Slag ◽  
Phosphate Fertilizers ◽  
Rock Phosphates ◽  
Joint Investigation

The results of over 400 field experiments testing different kinds of phosphate fertilizers are summarized and are discussed with special reference to the reactions of the soils used. The classifications were:‘very acid’ soils—pH below 5·5, ‘acid soils’— pH 5·6 to 6·5, neutral soils—pH over 6·5. All comparisons are made in terms of fertilizers supplying the same amounts of total phosphorus.In war-time experiments Gafsa and Morocco rock phosphates were about two-thirds as efficient as superphosphate for swedes and turnips grown on very acid soils. In 1951–3 experiments on very acid and acid soils Gafsa phosphate was practically equivalent to superphosphate for swedes, but for potatoes it was as effective as only one-third as much phosphorus supplied as superphosphate; on neutral soils Gafsa phosphate was useless. For establishing grassland on acid soils Gafsa and Morocco phosphate were equivalent to about onethird as much phosphorus supplied as high-soluble basic slag. Rock phosphates were somewhat more effective for promoting growth of established grassland but they remained inferior to high-soluble basic slags and to superphosphate. Curacao rock phosphate was roughly equivalent to Gafsa phosphate for swedes and grass. Florida pebble phosphate was much less effective and was judged unsuitable for direct application. Mixtures of rock phosphate with superphosphate were not more efficient than equivalent amounts of the separate components used correctly.Silicophosphate was practically as effective as superphosphate for swedes grown on very acid and acid soils; it was less efficient on neutral soils. For potatoes silicophosphate was nearly as effective as superphosphate on very acid soils; it was much less efficient on acid and neutral soils. Silicophosphate was roughly equivalent to high-soluble basic slag for grassland.Mixtures of superphosphate with lime, serpentine, and low-grade basic slag were prepared, most of the water-soluble phosphorus being converted to insoluble forms. In experiments on swedes and potatoes these basic superphosphates were not superior to untreated superphosphate. For establishing grassland on very acid soils, the mixtures were slightly superior to ordinary superphosphate.Dicalcium phosphate was practically equivalent to superphosphate for swedes on all groups of soils. For potatoes dicalcium phosphate was more efficient than superphosphate on very acid soils, on less acid and neutral soils it was inferior to superphosphate.

Effects of Ground Rock Phosphate and Elemental S on Yield and P Uptake of Maize in Western Kenya

1981 ◽  
Vol 17 (4) ◽  
pp. 383-387 ◽  
Author(s):  
A. R. Bromfield ◽  
I. R. Hancock ◽  
D. F. Debenham
Keyword(s):  
Rock Phosphate ◽  
P Uptake ◽  
Cost Ratio ◽  
Single Superphosphate ◽  
Western Kenya ◽  
The Third ◽  
Maize Yields ◽  
P Recovery ◽  
Effect On Yield

SUMMARYThe effect on maize yields of ground rock phosphate, alone or mixed with sulphur in either of two proportions, and of single-superphosphate, was measured at five consecutive harvests. At the first harvest single-superphosphate increased yield by 1.54 t and the best of the mixtures by 0.56 t grain/ha. Ground rock phosphate alone had no effect on yield. At the third harvest there were no yield differences between sources; because yields produced by rock phosphate and the mixtures improved. The cumulative increase in yield produced by single-superphosphate was 3.58 t/ha and by rock phosphate 2.69 t grain/ha, but because the fertilizer cost ratio was 3:1, additional grain produced by rock phosphate cost half as much. The apparent P recovery ranged from 5.40 to 8.28 kg/ha, with most from single-superphosphate and least from the mixture containing most elemental-S.

The marine environment and its influence on seafaring and maritime routes in the prehistoric Aegean

2008 ◽  
Vol 11 (2-3) ◽  
pp. 199-222 ◽  
Author(s):  
Despoina Papageorgiou
Keyword(s):  
Early Growth ◽  
Environmental Data ◽  
Sea Surface ◽  
Dense Network ◽  
Aegean Area ◽  
The Third ◽  
Aegean Islands ◽  
Surface Circulation ◽  
Sea Currents ◽  
Prehistoric Aegean

This article seeks to illustrate the decisive contribution of the sea environment and particularly the sea-surface circulation (which is determined by the circulation of sea currents and the winds) to the early growth of seafaring and maritime communications in the prehistoric Aegean. Given the means and techniques of navigation in that era, an attempt is made to reveal a dense network of sea routes which vessels could follow through the Aegean, in order to facilitate their trip. These sea routes are primarily based on environmental data and are confirmed concurrently by archaeological evidence and data of ancient sources. Therefore, it is evident that these sea routes played an important role not only in the early inhabitation of the Aegean islands and the foundation of coastal settlements throughout the Aegean area from the sixth millennium BC to the end of the third millennium BC, but in the development of the Aegean civilization during earlier prehistoric times as well.

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