The effect of rock phosphate properties on the extent of fertilizer dissolution in soils

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 209 ◽  
Author(s):  
JC Hughes ◽  
RJ Gilkes
Keyword(s):  
Rock Phosphate ◽  
High Availability ◽  
Unit Cell ◽  
Dicalcium Phosphate ◽  
Phosphate Fertilizers ◽  
Rock Phosphates ◽  
Monocalcium Phosphate ◽  
Rate Of Dissolution

Two soils, a West Australian Petroferric Udipsamment (WA4) and a Colombian Typic Haplustox (SA21) were incubated for up to 31 days with 23 phosphate fertilizers. These comprised 18 apatitic rock phosphates, three calcined rock phosphates, monocalcium phosphate and dicalcium phosphate. The fertilizers were mixed through the soils at rates of addition between 0.37 and 37 mg g-' soil. The extent and rate of dissolution of fertilizers were measured by determining changes in Ca using the ACa technique. Most dissolution generally occurred within one day for all fertilizers. The proportion of fertilizer that dissolved decreased with increasing rate of addition, and this proportion differed greatly between fertilizers (1-43% in WA4, 2-72% in SA21). All fertilizers dissolved to a greater extent in the Colombian soil. Calcined (1500�C) Queensland rock phosphate was the most soluble of the rock phosphates, which is consistent with its high availability to plants. The calcined iron-aluminium rock phosphates (Calciphos, Phospal) dissolved to a smaller extent than most of the apatitic rocks. The CaO/P2O5 ratio of the apatitic rock phosphate fertilizers was a slightly better predictor of the extent of dissolution than the apatite unit cell a dimension, although neither explained more than 60% of the variance. The present results are consistent with the accepted reactivity scale for the apatitic fertilizers, but the amount of each fertilizer which dissolved depended greatly on the soil to which it was applied.

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.

Evaluation of phosphate fertilizers: I. Immediate value of dicalcium phosphate, nitrophosphates, Gafsa rock phosphate basic slag and potassium metaphosphate for barley and ryegrass

1968 ◽  
Vol 70 (2) ◽  
pp. 131-138 ◽  
Author(s):  
G. E. G. Mattingly ◽  
A. Penny
Keyword(s):  
Total Phosphorus ◽  
Rock Phosphate ◽  
Growing Season ◽  
Water Soluble ◽  
Dicalcium Phosphate ◽  
Soluble Form ◽  
Soluble Phosphate ◽  
Basic Slag ◽  
Phosphate Fertilizers

SUMMARYThree granular nitrophosphates containing 5, 26 and 50 % of their total phosphorus in a water-soluble form, granular potassium metaphosphate, Gafsa rock phosphate and basic slag (both as powders) were compared with granular superphosphate and powdered dicalcium phosphate as standards in two annual experiments with ryegrass and in three experiments with barley.In 1960 total yields of ryegrass during a whole season were similar with all fertilizers. Nitrophosphate-5, Gafsa rock phosphate and basic slag acted more slowly than granular superphosphate and grass grew less well and took up less phosphorus during the first 12 weeks. Over the whole growing season more phosphorus was taken up by grass from powdered dicalcium phosphate and from granular potassium metaphosphate (0.5–2.0 mm) than from granular superphosphate (1.0–4.0 mm).Powdered dicalcium phosphate was equivalent to about 60% as much phosphorus applied as superphosphate to barley. Rock phosphate was almost inert and percentage granular superphosphate equivalents of basic slag and potassium metaphosphate were 22 and 23% respectively. Percentage superphosphate equivalents of the granular nitrophosphates were 1, 25 and 53% and almost equal to the water-soluble phosphate they contained.

Response of subterranean clover to rock phosphates as affected by particle size and depth of mixing in the soil

1974 ◽  
Vol 14 (70) ◽  
pp. 649 ◽  
Author(s):  
AM Alston ◽  
KW Chin
Keyword(s):  
Particle Size ◽  
Dry Matter ◽  
Rock Phosphate ◽  
Phosphorus Uptake ◽  
Subterranean Clover ◽  
Phosphorus Concentration ◽  
Dry Matter Yield ◽  
Rock Phosphates ◽  
Monocalcium Phosphate ◽  
Christmas Island

Samples of Christmas Island and Florida rock phosphates with different particle size ranges were applied to a phosphorus-deficient acid sandy soil. The rock phosphates were compared with monocalcium phosphate at various levels of addition of phosphorus. The fertilizers were mixed uniformly with either the top 1, 5, or 10 cm of the soil. Dry matter yield and phosphorus uptake in the tops of subterranean clover (Trifolium subterraneum) and the distribution (by weight) of the roots in the soil were determined. Monocalcium phosphate produced higher dry matter yields (tops and roots) than rock phosphates, even when the latter were applied in amounts containing four times the amount of phosphorus added as monocalcium phosphate. The concentration and uptake of phosphorus in the tops was also higher when monocalcium phosphate was applied, although the difference in concentration decreased as the plants matured. Dry matter yield and phosphorus concentration in the clover tops were increased by increasing the fineness of grinding of rock phosphate and by increasing the depth of mixing with the soil. Increasing the depth of mixing also produced a greater weight and more even distribution of roots. The yield of tops and roots was unaffected by the depth to which monocalcium phosphate was mixed, although shallow placement concentrated the distribution of the roots near the soil surface. Florida rock phosphate was a better source of phosphorus for subterranean clover than Christmas Island rock when the samples were coarsely ground, but both rocks were equally effective when ground to give 70 per cent < 100 mesh B.S.S.

Wheat yield responses to various phosphate fertilizers in South Australia

1972 ◽  
Vol 12 (54) ◽  
pp. 65 ◽  
Author(s):  
CL Rudd
Keyword(s):  
Calcium Phosphate ◽  
Rock Phosphate ◽  
Wheat Yield ◽  
South Australia ◽  
Calcium Pyrophosphate ◽  
Water Soluble ◽  
Phosphate Fertilizers ◽  
Rock Phosphates ◽  
Calcined Phosphate ◽  
Yield Responses

A number of phosphate fertilizers were tested as a source of phosphorus for wheat during three seasons (1967-1969) in the cereal growing areas of South Australia. The fertilizers were standard superphosphate, double superphosphate, calcium phosphate, two forms of calcined phosphate, a mixture of calcined phosphate with superphosphate, and untreated rock phosphate. Nine experiments were sown on a range of soils (pH 6.2 8.4) during the three years.At equivalent rates of total phosphorus, the water-soluble phosphates (superphosphate, double superphosphate) and the readily hydrolysed calcium pyrophosphate gave similar responses in all experiments. Water insoluble calcined and rock phosphates gave lower yields than superphosphate and, in most cases, the yields were not significantly greater than with no fertilizer.Uptake of phosphorus in the grain paralleled the grain yield differences between the fertilizers.

Defluorinated rock phosphate as a source of phosphorus for growing sheep

1975 ◽  
Vol 84 (2) ◽  
pp. 381-382 ◽  
Author(s):  
R. G. Hemingway ◽  
G. Fishwick
Keyword(s):  
Heat Treatment ◽  
Calcium Phosphate ◽  
Low Temperature ◽  
Rock Phosphate ◽  
Animal Feed ◽  
Dicalcium Phosphate ◽  
Rock Phosphates ◽  
Important Method ◽  
Phosphorus Sources ◽  
Growing Cattle

Defluorination of rock phosphate by heat treatment is an important method of producing phosphates suitable for animal feed. A variety of such products have been evaluated as phosphorus sources for ruminants, e.g. Beeson et al. (1945) recorded that a material produced at a low temperature (600°C) was unsatisfactory for steers, but Ammerman et al. (1957) indicated that a calcined calcium phosphate acidified with either sulphuric or phosphoric acids was fully as satisfactory as dicalcium phosphate for steers, but not for growing sheep. Wise, Wentworth & Smith (1961) and O'Donovan et al. (1965) recorded that defluorinated rock phosphates (produced by unspecified methods) were as useful as dicalcium phosphate for growing cattle. Arrington et al. (1963) have reported that 32P contained in reagent grade dicalcium phosphate was better retained by growing cattle than when present as a defluorinated rock phosphate.

Growth characters and yield of sorghum (Sorghum vulgare Pers.) as affected by contents of water–soluble P in triple superphosphate/dicalcium phosphate and triple superphosphate/rock phosphate mixtures

1972 ◽  
Vol 79 (3) ◽  
pp. 485-492 ◽  
Author(s):  
B. P. Govil ◽  
Rajendra Prasad
Keyword(s):  
Rock Phosphate ◽  
Water Solubility ◽  
Sandy Loam ◽  
Relative Effectiveness ◽  
Water Soluble ◽  
Dicalcium Phosphate ◽  
Soluble Phosphate ◽  
Triple Superphosphate ◽  
Rock Phosphates ◽  
Phosphorus Application

SUMMARYA field experiment was made during the rainy seasons of 1968 and 1969 on a sandy loam soil to study the response of Sorghum hybrid CSH–1 to phosphorus in relation to content of water-soluble phosphate in fertilizers. Triple superphosphate, dicalcium phosphate, rock phosphate (200-mesh), nitrophosphate and mixtures of triple superphosphate with dicalcium phosphate and rock phosphate in 3:1, 2:2 and 1:3 ratios were studied. The amounts of phosphorus applied were 30 and 60 kg P2O5/ha. Phosphorus application significantly affected dry matterproduced, plant height, days to 50% bloom, number of grains per ear, thousand-grain weight, stover and grain yield. Triple superphosphate and 3:1 triple superphosphate/dicalcium phosphate mixture were the most effective while rock phosphate and 1:3 triple superphosphate/rock phosphate mixture the least. Differences among sources were more marked in 1968 and at the higher amount i.e. 60 kg P2O5/ha. The response of sorghum to phosphorus was considerably lowered when the water solubility waa below 50% in triple superphosphate/dicalcium phosphate mixtures and below 75% in triple superphosphate/rock phosphate mixtures. Relative effectiveness was assessed by calculating ‘superphosphate equivalents’ and ‘multiple regressions’. Using superphosphate equivalents dicalcium phosphate, nitrophosphate and rock phosphates were 47–53%, 35–56% and 3–25%, respectively, as effective as triple superphosphate.

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.

scholarly journals Phosphorus availability of rock phosphates as compared with feed-grade phosphates for swine

2009 ◽  
Vol 38 (1) ◽  
pp. 90-98 ◽  
Author(s):  
Luiz Waldemar de Oliveira Souza ◽  
Anibal de Sant'Anna Moretti ◽  
Fernanda Marcussi Tucci ◽  
Nedilse Helena de Souza ◽  
Paulo Ademar Martins Leal ◽  
...  
Keyword(s):  
Rock Phosphate ◽  
Breaking Strength ◽  
Basal Diet ◽  
Relative Bioavailability ◽  
Phosphorus Addition ◽  
Rock Phosphates ◽  
Bone Parameters ◽  
Bone Ash ◽  
Calcium Phosphorus ◽  
Made In

One hundred ninety two swine were used in a trial to assess the relative bioavailability of phosphorus (RBP) in six phosphate sources. Phosphates were three feed grade phosphates (FP), two made in Brasil, and one USA made, and three rock phosphate samples (RP) originated from two mines sites in Brasil, and one mine site in Israel. Levels of calcium, phosphorus and fluorine in RP were 29, 12 and 1.7% (RP source 1), 33, 14 and 1.4% (RP source 2), and 30, 14 and 3.6% (RP source 3), respectively. Pigs were fed a corn-soybean meal basal diet (18% CP, 0.95% Lys, 0.75% Ca, 0.37% P) or the basal diet with 0.15% P from a standard purified grade calcium phosphate (SP), or with 0.15% P from experimental FP or RP. Each diet was fed to six pen replicates of four pigs per pen for 35 days (14.4 to 39.9 kg). Weight gain (WG), feed/gain (FG), plasma P (PP), bone ash (BA), and breaking strength of metacarpals and metatarsals (BS-MM) and femurs (BS-F) were improved by phosphorus addition. However, performance and bone parameters were depressed by RP, as compared to FP dietary supplementation. WG, BA, BS-MM and BS-F were regressed to P added, and slope-ratios were calculated to assess RBP in the FP and RP sources. The average bioavailability of P in the FP and RP sources, relative to SP, were 89 and 49% (WG), 112 and 49% (BA), 78 and 28% (BS-MM), and 101 and 52% (BS-F), respectively. Low animal performance and bone strength related to toxicity should be expected if rock phosphates are used to feed pigs.

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