Abstract
The agronomic effectiveness (yield and P uptake) of twelve granular, partially acidulated phosphate rock fertilizers (PAPR) and two finely ground, unacidulated phosphate rocks (PR) were compared to that of a single superphosphate in a long-term greenhouse experiment with lucerne (Medicago sativa L., cv. CUF101), grown in a low P sorbing, moderately acid, sandy loam soil of moderate P status (Paleustaf). The PAPRs were prepared from two unreactive PRs (Christmas Is. ‘A’ grade and Duchess rock from Queensland) and acidulated at two rates (25% and 50% on a H2SO4 to single superphosphate basis) with either H2SO4 or H3PO4. Additional products included H2SO4 PAPRs cogranulated with elemental S (10% w/w).
Superphosphate was consistently superior to all PRs and PAPRs in agronomic effectiveness throughout this two-year study. The most effective of the PAPRs were those that were 50% acidulated with H2SO4 and cogranulated with elemental S; this type of fertilizer from both rocks was approximately 2/3 as effective as superphosphate when relative agronomic effectiveness indices (RAE) were calculated from cumulative yields. The increase in agronomic effectiveness relative to superphosphate (RAE value) by the partial acidulation of the PR could be attributed to its effect of increasing the P solubility in the PAPR. A curvilinear relationship existed between the RAE values of PRs and PAPRs, measured from cumulative yield or P uptake data, and the percentage of the total P in each fertilizer that was in a soluble (water + citrate soluble) form. Cogranulation with elemental S (10% w/w) significantly displaced this relationship upwards by increasing the RAE of H2SO4 PAPRs by more than 50%. The maximum cumulative recovery of applied P by lucerne tops after five bulked harvests (fifteen consecutive harvests) was 61.5%, which occurred at the low application rate of superphosphate. The decline in the substitution value of PRs for superphosphate, that occurred with increasing P rates tended to be offset both by increasing the level of acidulation and by cogranulating the PAPR with elemental S.
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References
Attoe OJ and Olson RA (1966). Factors affecting rate of oxidation in soils of elemental sulfur and that added in rock phosphate-sulfur fusions. Soil Sci 101: 317–325
Blair GJ, Till AR and Smith RCG (1976) The phosphorus cycle — what are the sensitive areas? In: Blair GJ (ed.) The efficiency of phosphorus utilization. Reviews in Rural Science 3, University of New England, Armidale, NSW, Australia, pp 9–19
Bolland MDA (1985) Responses of serradella and subterranean clover to phosphorus from superphosphate and Duchess rock phosphate. Aust J Exp Agric 25: 905–912
Bolland MDA and Bowden JW (1984) The initial and residual value for subterranean clover of phosphorus from crandallite rock phosphate. Fert Res 5: 295–307
Bolland MDA and Barrow NJ (1988) Effect of level of applications on the relative effectiveness of rock phosphate. Fert Res 33: 1061–71
Bolland MDA, Bowden JW, D'Antuono MF and Gilkes RJ (1984) The current and residual value for superphosphate, Christmas Island C-grade ore, and Calciphos as fertilizers for a subterranean clover pasture. Fert Res 5: 335–354
Fox RL and Kamprath EJ (1978) Phosphate absorption isotherms evaluating phosphate requirements of soils. Soil Sci Soc Am Proc 34: 902–907
Friesen DK, Sale PWG and Blair GJ (1987) Long-term greenhouse evaluation of partially acidulated phosphate rock fertilizers: I. Effect of acidulant and degree of acidulation on availability of P from two phosphate rocks. Fert Res 13: 31–44
Freisen DK, Sale PWG and Blair GJ (1987) Long-term greenhouse evaluation of partially acidulated phosphate rock fertilizers: II. Effect of cogranulation with elemental S on availability of P from two phosphate rocks. Fert Res 13: 45–54
Hammond LL, Chien SH and Polo JR (1980) Phosphorus availability from partial acidulation of two phosphate rocks. Fert Res 1: 37–49
Harris DJ, (1985) Comparison of phosphate rock sources in two benchmark soils. In: Silva JA (ed.) Soil-based Agrotechnology Transfer. Univeristy of Hawaii, Hawaii, pp 117–125
Jones RF and Field JBF (1976) A comparison of biosuper and superphosphate on a sandy soil in the monsoonal tropics of north Queensland. Aust J Exp Agric Anim Husb 16: 99–102
Mackay AD, Gregg PEH and Syers JK (1984) Field of evaluation Chatham Rise phosphorite as a phosphatic fertilizer for pasture. New Zeal J Agric Res 27: 65–82
Olsen RH and Sommers LE (1982) Phosphorus. In: Page AL, Miller RH and Keeney DR (eds.) Methods of Soil Analysis, Part 2. Chemical and Microbiological Properties, 2nd edn., ASA; Madison, WI, USA pp 41–422
Palmer B and Jessop RS (1982) The relative value of water-soluble and ammonium-citrate-soluble phosphorus for wheat production. J Agric Sci, Camb 98: 467–610
Rajan SSS (1981) Use of low grade phosphate rocks as biosuper fertilizer. Fert Res 2: 199–210
Rajan SSS (1982) Availability to plants of phosphate from ‘biosuper’ and partially acidulated phosphate rocks. New Zealand J Agric Res 25: 355–361
Rajan SSS (1986) Phosphate rocks and phosphate rock/sulphur granules for hill country pasture. New Zealand J Agric Res 14: 313–318
Rajan SSS (1987) Phosphate rocks and phosphate rock/sulphur granules as phosphate fertilizers and their dissolution in soil. Fert Res 11: 43–60
Rajan SSS, Gillingham AG, O'Connor MB, Percival NA and Gray MG (1987) Ground phosphate rock as fertilizers for pastures. In: White RE and Currie LD (eds.) The use of Reactive Phosphate Rocks and their Derivatives as Fertilizers. Massey University, Palmerston North, New Zealand, pp 78–83
Smith AN (1983) Australian dependence on phosphorus. In: Costin AB and Williams CH (eds.) Phosphorus in Australia. Centre for Resources and Environmental Studies, A.N.U, Canberra, Australia, pp 73–91
Soil Survey Staff (1975) Soil Taxonomy: A basic system of soil classification for making and interpreting soil surveys. USDA-SCS Agric Handbook No. 436, U.S. Govt. Printing Office, Washington, D.C.
Thomas RL, Sheard RW and Moyer JR (1967) Comparison of conventional and automated procedures for nitrogen, phosphorus and potassium analysis of plant material using a single digestion. Agron J 59: 240–243
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Sale, P.W.G., Friesen, D.K. & Blair, G.J. Long-term greenhouse evaluation of partially acidulated phosphate rock fertilizers. Fertilizer Research 29, 295–307 (1991). https://doi.org/10.1007/BF01052399
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DOI: https://doi.org/10.1007/BF01052399