Agronomic effectiveness of partially acidulated phosphate rock as influenced by soil phosphorus-fixing capacity

1989 ◽  
Vol 120 (2) ◽  
pp. 159-164 ◽  
Author(s):  
S. H. Chien ◽  
L. L. Hammond
Keyword(s):  
Phosphate Rock ◽  
Soil Phosphorus ◽  
Partially Acidulated Phosphate Rock ◽  
Agronomic Effectiveness

scholarly journals Plant- and microbial-based mechanisms to improve the agronomic effectiveness of phosphate rock: a review

2006 ◽  
Vol 78 (4) ◽  
pp. 791-807 ◽  
Author(s):  
Melissa M. Arcand ◽  
Kim D. Schneider
Keyword(s):  
Phosphate Rock ◽  
Agricultural Soils ◽  
Low Cost ◽  
Soil Phosphorus ◽  
Future Research ◽  
Available Phosphorus ◽  
Limiting Factor ◽  
Agronomic Effectiveness ◽  
Ongoing Research ◽  
Organic Acid Production

Deficiency in plant-available phosphorus is considered to be a major limiting factor to food production in many agricultural soils. Mineral resources are necessary to restore soil phosphorus content. In regions where conventional fertilizers are not used due to cost limitations or to mitigate adverse environmental effects, local sources of phosphate rock are being increasingly recognized for potential use as alternative phosphorus fertilizers. The main obstacle associated with using directly applied ground phosphate rock is that the phosphate released is often unable to supply sufficient plant-available phosphorus for crop uptake. Plantand microbial-based mechanisms are low-cost, appropriate technologies to enhance the solubilization and increase the agronomic effectiveness of phosphate rock. Common mechanisms of phosphate rock dissolution including proton and organic acid production will be reviewed for both plants and microorganisms. This review will also address possibilities for future research directions and applications to agriculture, as well as highlight ongoing research at the University of Guelph, Guelph, Canada.

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.

Agronomic effectiveness of partially acidulated phosphate rock fertilisers in selected New Zealand soils

1995 ◽  
Vol 35 (3) ◽  
pp. 387 ◽  
Author(s):  
LM Condron ◽  
HJ Di ◽  
KM Goh ◽  
AS Campbell ◽  
R Harrison
Keyword(s):  
New Zealand ◽  
Phosphate Rock ◽  
Phosphorus Uptake ◽  
Partially Acidulated Phosphate Rock ◽  
Agronomic Effectiveness ◽  
Single Superphosphate ◽  
Relative Agronomic Effectiveness ◽  
Pot Trials ◽  
Highly Correlated ◽  
Manufacture Plant

The agronomic performances of some longlife superphosphate (LSP) and partially acidulated phosphate rock (PAPR) fertilizers were compared with single superphosphate in glasshouse pot trials over 9-10 months using a range of New Zealand soils. The fertilizers used differed in the type (origin) of phosphate rock (PR), the acid to rock ratio used in the production of LSP, percentage acidulation of PAPR, and incorporation of elemental sulfur into LSP. The agronomic effectiveness of the fertilizers studied was primarily influenced by the type of PR and percentage acidulation of PAPR, but not by the acid to rock ratio. Variations in the agronomic effectiveness of LSP and PAPR fertilizers made from different PRs did not reflect the relative solubilities of the original PRs. This was mainly attributed to alterations in the chemistry and consequent solubility of PR which occurred during fertilizer manufacture. Plant phosphorus uptake was highly correlated with fertilizer solubility in 2% citric and 2% formic acids. The relative agronomic effectiveness of LSP and PAPR fertilizers was not significantly related to any single soil property.

The agronomic effectiveness of reactive phosphate rocks 1. Effect of the pasture environment

1997 ◽  
Vol 37 (8) ◽  
pp. 921 ◽  
Author(s):  
P. W. G Sale ◽  
R. J. Gilkes ◽  
M. D. A. Bolland ◽  
P. G. Simpson ◽  
D. C. Lewis ◽  
...  
Keyword(s):  
North Carolina ◽  
Phosphate Rock ◽  
Surface Soil ◽  
Annual Rainfall ◽  
Triple Superphosphate ◽  
Agronomic Effectiveness ◽  
P Sorption ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
Very High

Summary. The agronomic effectiveness of directly applied North Carolina reactive phosphate rock was determined for 4 years from annual dry matter responses at 26 permanent pasture sites across Australia as part of the National Reactive Phosphate Rock Project. Fertiliser comparisons were based on the substitution value of North Carolina reactive phosphate rock for triple superphosphate (the SV50). The SV50 was calculated from fitted response curves for both fertilisers at the 50% of maximum yield response level of triple superphosphate. The reactive phosphate rock was judged to be as effective as triple superphosphate in the 1st year (and every year thereafter) at 4 sites (SV50 >0.9), and was as effective by the 4th year at 5 sites. At another 9 sites the reactive phosphate rock was only moderately effective with SV50 values between 0.5 and 0.8 in the 4th year, and at the final 8 sites it performed poorly with the 4th year SV50 being less than 0.5. Pasture environments where the reactive phosphate rock was effective in the 1st year were: (i) those on sandy, humic or peaty podsols with an annual rainfall in excess of 850 mm; (ii) those on soils that experienced prolonged winter inundation and lateral surface flow; and (iii) tropical grass pastures in very high rainfall areas (>2300 mm) on the wet tropical coast on North Queensland. The highly reactive North Carolina phosphate rock became effective by the 4th year at sites in southern Australia where annual rainfall exceeded 700 mm, and where the surface soil was acidic [pH (CaCl2) <5.0] and not excessively sandy (sand fraction in the A1 horizon <67%) but had some phosphorus (P) sorption capacity. Sites that were unsuitable for reactive phosphate rock use in the medium term (up to 4 years at least) were on very high P-sorbing krasnozem soils or high P-sorbing lateritic or red earth soils supporting subterranean-clover-dominant pasture, or on lower rainfall (< 600 mm) pastures growing on soils with a sandy A1 horizon (sand component >84%). No single environmental feature adequately predicted reactive phosphate rock performance although the surface pH of the soil was most closely correlated with the year-4 SV50 (r = 0.67). Multiple linear regression analysis found that available soil P (0–10 cm) and the P sorption class of the surface soil (0–2 cm), together with annual rainfall and a measure of the surface soil"s ability to retain moisture, could explain about two-thirds of the variance in the year-4 SV50 . The results from this Project indicate that there are a number of specific pasture environments in the higher rainfall regions of Australia where North Carolina reactive phosphate rock can be considered as an effective substitute P fertiliser for improved pasture.

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.

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