The use of substitution values for characterising fertiliser performance

1997 ◽  
Vol 37 (8) ◽  
pp. 913
Author(s):  
D. A. Ratkowsky ◽  
S. B. Tennakoon ◽  
P. W. G. Sale ◽  
P. G. Simpson
Keyword(s):  
Phosphate Rock ◽  
Statistical Tests ◽  
Effective Means ◽  
Field Trials ◽  
Water Soluble ◽  
Soluble Phosphate ◽  
Phosphate Rocks ◽  
High Performing ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock

Summary. The substitution value, or horizontal comparison between a fertiliser and some high-performing reference fertiliser, is shown to be a powerful and effective means of ranking the performance of various reactive phosphate rock fertilisers relative to a water-soluble phosphate such as a superphosphate. To take account of the variability due to random error in fertiliser field trials, the use of a standardised score, one measuring the relative departure of the substitution value from that expected for the standard fertiliser, is shown to be a suitable statistic for general use. Cluster analyses using these z-scores as input data can lead to appropriate decision making such as, for example, grouping experimental sites into: (i) those which perform as well as water-soluble phosphate, (ii) those which are somewhat worse than water-soluble phosphate, and (iii) those which are much worse than water-soluble phosphate. Substitution values obtained for different reactive phosphate rocks were compared both within and between sites, using appropriate statistical tests of significance. This approach assisted in ranking the performance of the 5 reactive phosphate rocks and the partially acidulated phosphate rock studied in the National Reactive Phosphate Rock Project, and helped predict which ones are likely to be suitable for use in differing environments.

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.

RPR revisited (1): Research, recommendations, promotion and use in New Zealand

2012 ◽  
pp. 255-268
Author(s):  
B.F. Quin ◽  
M. Zaman
Keyword(s):  
New Zealand ◽  
Phosphate Rock ◽  
Field Trials ◽  
Laboratory Research ◽  
Reactive Phosphate ◽  
Run Off ◽  
Specific Advice ◽  
Reactive Phosphate Rock ◽  
Research Recommendations

Reactive phosphate rock (RPR) has been studied extensively in field trials and laboratory research in New Zealand since the 1930s. This paper looks at the different approaches to research over the decades, at what conclusions were drawn, at the recommendations made to farmers, and at the commercial promotion and sales of RPR. It is not an exhaustive literature review, but sufficiently comprehensive to demonstrate the large amount of research conducted, and to document the important issues that have arisen, particularly with respect to advice being given to farmers. RPR research has suffered from a series of mishaps which have hindered, in one way or another, the results being accurately interpreted and passed on clearly to farmers. There is a need for specific advice for farmers regarding managing or minimising any lag in production following a switch to RPR. New Zealand's grazed pastures, water quality and "clean and green" image internationally are closely interlinked. Given the proven significant reduction in P losses in run-off to waterways with RPR, the conditions in which RPR can be successfully used in New Zealand's pastoral agriculture have been reassessed. Key words: reactive phosphate rock, RPR, superphosphate, SSP, TSP, PAPR, long-term comparisons, plot trials, grazing trials, fertiliser recommendations, history

scholarly journals The long-term effectiveness of reactive phosphate rock as a phosphate fertiliser for New Zealand pastures

1990 ◽  
pp. 101-104 ◽  
Author(s):  
A.G. Sinclair ◽  
C.B. Dyson ◽  
P.W. Shannon
Keyword(s):  
New Zealand ◽  
Phosphate Rock ◽  
Field Trials ◽  
Superior Performance ◽  
Single Superphosphate ◽  
Reactive Phosphate ◽  
Application Rates ◽  
Phosphate Retention ◽  
Reactive Phosphate Rock ◽  
Sechura Phosphate Rock

Sechura reactive phosphate rock (SPR) and triple superphosphate (TSP) have been compared as phosphate fertihsers for pastures in a series of 19 field trials dispersed throughout New Zealand, each continuing for 3-6 years. Both fertilisers were applied annuaIly at 4 rates. In the first 2 years SPR was much less effective at increasing dry matter yields than TSP, but its performance improved markedly with time. In year 6 SPR outyielded TSP at alI application rates for all sites combined. The relative performance of SPR and TSP differed markedly at different sites. Very high soil phosphate retention and a combination of low moisture and high pH appeared to be unfavourable for SPR performance. In most sites SPR was equal or superior to TSP by year 6. SPR substantially raised molybdenum concentration in clovers, and this may have contributed to its superior performance at some sites. As TSP and single superphosphate were equally effective, the good performauce of SPR and the relative cheapness of reactive phosphate rocks suggest an important role for the latter on New Zealand pastures. Keywords Sechura phosphate rock, reactive phosphate rock, RPR, superphosphates, phosphate fertilisers

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.

Effect of reactive phosphate rocks and water-soluble phosphorus fertilisers on extractable phosphorus concentrations in soil

1997 ◽  
Vol 37 (8) ◽  
pp. 1009 ◽  
Author(s):  
N. K. Fleming ◽  
M. D. A. Bolland ◽  
M. A. Gilbert
Keyword(s):  
Phosphate Rock ◽  
Water Soluble ◽  
Soil Test ◽  
Phosphate Rocks ◽  
Water Soluble P ◽  
Reactive Phosphate ◽  
Soluble Phosphorus ◽  
Soil Test P ◽  
Soluble P ◽  
Pasture Yield

Summary. Soil samples were collected each year from all plots at all sites in the National Reactive Phosphate Rock Project and analysed for bicarbonate-soluble phosphorus (P) using the Colwell procedure (soil test P). The relationship between soil test P and the level of P applied was adequately described by a linear equation. The slope coefficient of this equation provides a measure of the extractability of P from soil treated with a particular fertiliser and has been termed the ‘extractability’ for that particular fertiliser at that site. Extractability values were used to estimate phosphate rock effectiveness; this was done by dividing the extractability for each phosphate rock by the extractability of the reference water-soluble P fertiliser to provide a relative soil extractability (RSE). There was a good agreement between the RSE for a phosphate rock and its substitution value for water-soluble P fertiliser, which is a measure of fertiliser effectiveness based on pasture yield. Estimates of fertiliser effectiveness, based on increases in soil test P values, also agreed with estimates based on pasture yield with respect to the ranking of different P fertilisers, and the ranking of phosphate rocks in order of their reactivity. Simple and multiple linear regression analyses were used to identify relationships between a range of soil properties and extractability values across sites, but no relationships were found.

scholarly journals Summary of eleven long-term field trials with 'Longlife' phosphatic fertiliser

1992 ◽  
pp. 35-40
Author(s):  
S.F. Ledgard ◽  
B.S. Thorrold ◽  
A.G. Sinclair ◽  
S.S.S. Rajan ◽  
D.C. Edmeades
Keyword(s):  
New Zealand ◽  
Phosphate Rock ◽  
Field Trials ◽  
Triple Superphosphate ◽  
Single Superphosphate ◽  
The North ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
Term Field

Longlife' phosphatic fertiliser is manufactured in New Zealand by mixing reactive phosphate rock (RPR) with single superphosphate (SSP) when the SSP is at an ex-den stage. Commercially produced Longlife (70:30 SSP:RPR) was evaluated in 6 field mowing trials in the North Island over 3 or4 years. Also, a 5050 (SSP:RPR) Longlife-type product was examined in 5 field trials throughout New Zealand over 5 or 6 years. Longlife was compared against SSP and/or triple superphosphate (TSP) in all trials, and RPR treatments were included in 7 trials. In all trials with commercially produced Longlife, the pasture response to Longlife tended to be less than that to SSP or TSP in the first 2 years and was significantly different (P 6.0 and/or rainfall ~800 mm/year). Keywords field trials, Longlife, phosphate, reactive phosphate rock, superphosphate

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 Direct application of reactive phosphate rock on improving maize yield in tidal swampland

2021 ◽  
Vol 648 (1) ◽  
pp. 012175
Author(s):  
A F Siregar ◽  
Husnain ◽  
I W Suastika ◽  
N P S Ratmini ◽  
I A Sipahutar ◽  
...  
Keyword(s):  
Phosphate Rock ◽  
Maize Yield ◽  
Direct Application ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock
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