A comparison of values for initial and residual effectiveness of rock phosphates measured in pot and field experiments

1988 ◽  
Vol 28 (6) ◽  
pp. 753 ◽  
Author(s):  
AJ Weatherley ◽  
MDA Bolland ◽  
RJ Gilkes

The effectiveness of Calciphos (500�C calcined calcium-aluminium C-grade rock phosphate from Christmas Island), Queensland rock phosphate (low carbonate substituted apatite, from Duchess deposit, Northern Queensland [QRP]), and granular North Carolina rock phosphate (highly carbonate substituted apatite from U.S.A. [NCRP]) were compared with the effectiveness of monocalcium phosphate (MCP) fertilisers in pot and field experiments. Three different lateritic soils from south-western Australia and different plant species were used. In the pot experiment, the effectiveness of the fertilisers was measured relative to freshly applied MCP for 5 successive crops. Subterranean clover, oats, triticale and barley were grown for about 1 month before harvesting. In the field experiment, the same plants were grown, and the effectiveness of the fertilisers was measured relative to freshly applied triple superphosphate for 3 successive years. On a dry matter yield basis, the effects of freshly applied rock phosphate dressings measured in the pot experiment were in a similar range to those measured in the field experiment for the same soil types, and the same plant species, indicating that pot trials can substitute for field trials for the evaluation of the initial effectiveness of fertilisers. However, the residual effectiveness values for both MCP and the RPs were generally much lower for the pot experiment, indicating that pot experiments cannot replace long-term field experiments for the reliable measurement of residual effectiveness of fertilisers. For the pot experiment, the relative effectiveness values of freshly applied NCRP and Calciphos for all soils were 0.2-0.3 and 0.1-0.2 respectively. The corresponding values for the field experiment were 0.1-0.3 for NCRP and 0.1 for Calciphos. For the pot experiment, the relative effectiveness of freshly applied QRP on all soils ranged from 0.03 to 0.1, compared with from 0.1 to 0.3 for the field experiment. The relative effectiveness of all fertilisers declined markedly with successive crops (i.e. crops 2-5) in the pot experiment, whereas in the field experiment the relative effectiveness of QRP and NCRP showed no systematic change for the 3-years of the experiment. For the pot experiment the relative effectiveness of residual MCP decreased to about 0.3, 0.2 and 0.1, compared with 0.5, 0.2 and 0.5 for the field experiment for West Dale, South Bodallin and Gibson soils, respectively. For the pot experiment and for all soils the residual relative effectiveness of NCRP and Calciphos was about 0.01- 0.04, compared with 0.003-0.02 for QRP. For the field experiment the corresponding values were 0.05-0.2 for NCRP and Calciphos and 0.01-0.1 for QRP. For both the pot and the field experiments the relationship between yield and phosphorus content was sometimes dependent on fertiliser type.


1986 ◽  
Vol 26 (2) ◽  
pp. 217 ◽  
Author(s):  
MDA Bolland ◽  
AJ Weatherley ◽  
RJ Gilkes ◽  
JW Bowden

The effectiveness, as a phosphate fertilizer, of granular reactive rock phosphate (carbonate substituted apatite from North Carolina, U.S.A.), granular triple superphosphate and partly powdered Duchess non-reactive rock phosphate (low carbonate apatite from north-eastern Australia) was compared in three field experiments on different soil types in different climatic regions of south-western Australia. Calciphos (finely ground calcined crandallite rock phosphate from Christmas Island) was included in one experiment. The rock phosphates were incorporated into the soil and their effectiveness was compared with both topdressed and incorporated superphosphate. Different species were grown at each site (barley, triticale and subterranean clover). As determined on the basis of relative amounts of fertilizer required for constant yield, the effectiveness of all the rock phosphates relative to incorporated superphosphate was very low at each site throughout the growth of each species. Fertilizer effectiveness of rock phosphates was about one-fifth that of superphosphate for barley, and one-tenth for triticale and clover. The maximum yield obtained from rock phosphate was generally 88-100% that obtained from superphosphate. Incorporation did not greatly affect the effectiveness of superphosphate.



1987 ◽  
Vol 27 (5) ◽  
pp. 647 ◽  
Author(s):  
MDA Bolland ◽  
MJ Baker ◽  
RJ Lunt

The initial and residual effectiveness of superphosphate, Christmas Island C-grade ore (C-ore) and 500�C heated (calcined) C-ore (Calciphos) was measured on a deep, very sandy soil near Badgingarra, W.A. Different levels of each fertiliser were applied once only in May 1980. Yields of lupins (1980 and 1983) and subterranean clover (1981) were used to determine the effectiveness of the fertilisers, and in 1986 the residual value of the fertilisers was measured for wheat, oats, and barley, relative to freshly applied superphosphate. Samples of the top 10 cm of soil were collected each January-February for soil tests for P which were compared to plant yields measured in the following spring (Aug.-Dec.). Superphosphate was the most effective fertiliser, though its effectiveness declined by about 50% between years 1 and 2, and by a further 25% between years 2 and 4. C-ore was only about one-tenth as effective as superphosphate in the year of application, and its effectiveness declined by about 40% between years 1 and 2, and by a further 15% between years 2 and 4. Calciphos was about one-fifth as effective as superphosphate in the year of application, and its effectiveness declined by about 40% between years 1 and 2, and remained approximately constant between years 2 and 4. In 1986, the effectiveness of 1980 applied superphosphate was between about one-quarter to one-fifth as effective as freshly applied superphosphate for wheat, oats and barley, and the 1980 applied C-ore and Calciphos were about 15% as effective as freshly applied superphosphate. The amount of P extracted by sodium bicarbonate from soil fertilised with superphosphate decreased by about 50% between years 2 and 3, by a further 20% between years 3 and 4, and by a further 15% between years 4 and 7. For soil treated with Calciphos, the amount of extractable P doubled between years 2 and 3 and thereafter remained approximately constant. Very little P was extracted from soil fertilised with C-ore. Separate calibration curves were required in most cases for the relationship between yield and soil test values for superphosphate and rock phosphate in 1981 and 1983, and for each fertiliser and species in 1986. A substantial amount of superphosphate-added P (50-70%) and about 20% of rock phosphate-added P had leached below 50 cm of the topsoil 6 years after application.



1988 ◽  
Vol 28 (5) ◽  
pp. 655 ◽  
Author(s):  
MDA Bolland ◽  
RJ Gilkes ◽  
MFD' Antuono

Plant responses to apatite rock phosphates and Calciphos, a calcined calcium iron-aluminium rock phosphate fertiliser, have been measured in many pot and field experiments in Australia, but there is no consistent view of the agronomic effectiveness of these fertilisers. Quantitative indices of the effectiveness of freshly applied rock phosphates relative to freshly applied superphosphate (relative effectiveness or RE values) have been calculated from the data for 164 Australian pot and field experiments on the basis of the substitution value of the rock phosphates for superphosphate. RE values range from <0.1 to 2.5, with the mean value for apatite rock phosphates being 0.26 compared with 0.42 for Calciphos. Statistical analysis of the data demonstrate that variations in RE values were primarily due to systematic differences in experimental design and fertiliser solubility, and not to differences in soil pH, plant species, the capacity of the soil to adsorb P and mean annual rainfall. All RE values >0.4 were obtained from experiments in which only 1 or 2 levels of fertiliser were applied to soils that were poorly responsive to applied P; thus it was not possible to define the complete response curves required to obtain precise values of RE. In most cases, RE values were < 0.4 for experiments in which several levels of fertiliser P were applied to highly P-responsive soils so that complete response curves were defined and precise values of RE estimated. The effectiveness of previously applied rock phosphate (i.e, residual value) remained low and approximately constant for several years after application, being 5-30% as effective as freshly applied superphosphate for the various experiments. The corresponding average value of the relative effectiveness of superphosphate declined by 40% in the first year after application, by a further 15% in the second year, and by a further 30% over the remaining 6 years. However, the magnitude of these declines in relative effectiveness differed substantially between individual sites. The residual value of both the superphosphate and rock phosphate fertilisers appears not to have been systematically influenced by soil type, soil pH, the capacity of the soil to adsorb P, mean annual rainfall, and whether the fertilisers were topdressed or were incorporated. However, there is a need for additional experiments to investigate the influence of these factors on fertiliser effectiveness. It is concluded that, on the basis of published data, rock phosphate fertilisers cannot be regarded as economic substitutes for fertilisers containing water-soluble P for most agricultural applications in Australia. This is because, relative to freshly applied superphosphate, the fertiliser effectiveness of rock phosphates is low in the year of application and it remains low in subsequent years so that uneconomical, very high rates of application of rock phosphate are required.



1956 ◽  
Vol 48 (1) ◽  
pp. 74-103 ◽  
Author(s):  
G. W. Cooke

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.



1981 ◽  
Vol 97 (1) ◽  
pp. 197-203 ◽  
Author(s):  
H. S. Hundal ◽  
B. R. Arora ◽  
G. S. Sekhon

SUMMARYNitric phosphates containing 80, 50 and 30% water-soluble phosphorus, and Mussoorie rock phosphate, alone or with Amjhore pyrites, farmyard manure or straw, were compared relative to concentrated superphosphate for each of three cycles of a clusterbean–wheat and a groundnut–wheat rotation. Both the field experiments were made on alkaline P-deficient Samana sands. All phosphatic fertilizers were applied to each crop at the rate of 10, 20 and 30 kg P/ha. Dry forage of clusterbean, groundnut pods and grain yield of wheat were measured. The model of concurrent straight line response was employed to calculate availability coefficient ratios which express the relative effectiveness of the different phosphatic fertilizers.Nitric phosphate containing 80 % water-soluble phosphorus and concentrated superphosphate were almost equal in their effectiveness in both 3-year rotational studies of clusterbean–wheat and groundnut–wheat. The relative efficiency of the nitric phosphates increased with the amount of water-soluble phosphorus they contained. Mussoorie rock phosphate was the least effective source of fertilizer phosphorus, although its efficiency is considerably higher for the legume clusterbean and for groundnut than for the cereal wheat. The efficiency of Mussoorie rock phosphate increased when it was mixed with the soil together with Amjhore pyrites, farmyard manure and straw respectively. These materials were more effective for clusterbean and groundnut than for wheat.



1974 ◽  
Vol 14 (70) ◽  
pp. 649 ◽  
Author(s):  
AM Alston ◽  
KW Chin

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.



Soil Research ◽  
1987 ◽  
Vol 25 (4) ◽  
pp. 555 ◽  
Author(s):  
MDA Bolland ◽  
DG Allen

Different amounts of superphosphate, crandallite-millisite rock phosphate (three different samples of C-ore from Christmas Island), 500�C calcined C-ore (three different samples of Calciphos) and apatite rock phosphate (two different samples from the Duchess deposit, Queensland) were applied once only in May 1977 on lateritic soil in Western Australia. Samples of the top 10 cm of soil were collected in the summer (January-February) of 1979 and 1980 for measurement of extractable soil phosphate by the Colwell, Olsen and Bray soil tests, and the data were compared with dry matter production of subterranean clover pasture in the following spring (August). For each fertilizer in each year, the Olsen and Brayl soil test values (as dependent variables) were closely correlated with the Colwell soil test values (independent variable), and the Bray 1 soil test (dependent variable) was closely correlated with the Olsen soil test (independent variable). For the relationship between yield and soil test values, separate calibrations were required in most cases for each fertilizer and each soil test, and these calibrations showed large differences in two successive years. None of the soil tests was significantly better for predicting clover yields for the different fertilizers applied two and three years previously.



Soil Research ◽  
1991 ◽  
Vol 29 (2) ◽  
pp. 215 ◽  
Author(s):  
MG Whitten ◽  
GSP Ritchie

Cadmium (Cd) may accumulate in soils which have been regularly fertilized with phosphate fertilizers which contain Cd originating in rock phosphate. Soil was taken from three sites in the wheatbelt of Western Australia which were estimated to have received different amounts of phosphate fertilizer over the past decade. The pH was adjusted with dilute HCl or CaCO3. No Cd was added experimentally. The concentration of Cd in the whole tops of Trifolium subterraneum cv Mt Barker grown in a glasshouse pot experiment increased from 0-2-0.8 �g g-1 dry wt at pH 6 -6-6.9 (1:50-01 M CaCl2) to 2-4 �g g-1 at pH 4.1-4.2. The highest concentration of Cd in the plant tops at any particular pH occurred on the soil which had the highest concentration of P in the CaCl2 extract. There was a linear relationship between the concentration of Cd in the whole tops of sub-clover and the concentration of Cd in the CaCl2 extracts which was independent of site. The concentration of Cd in the CaCl2 extracts was a function of pH and concentration of P in the CaCl2 extract.



1988 ◽  
Vol 28 (1) ◽  
pp. 83 ◽  
Author(s):  
MDA Bolland ◽  
AJ Weatherley ◽  
RJ Gilkes

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.



1972 ◽  
Vol 79 (3) ◽  
pp. 485-492 ◽  
Author(s):  
B. P. Govil ◽  
Rajendra Prasad

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.



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