Abstract
Proliferation of new phosphatic fertilizers with diverse chemical properties necessitates much agronomic evaluation including comparison in field experiments. If such experiments lack the power to detect real and economically important differences between fertilizers, there is a danger of inferior products entering the fertilizer market. The ability of field experiments to detect differences in plant yield from different fertilizers depends not only on the intrinsic differences between fertilizers but also on site responsiveness to phosphate, experimental variability and degree of replication. Biometrical guidelines are provided to assist in the design of powerful field experiments and a formula is developed for determining the replication required to detect differences in specific situations. The number of replications required to have a high probability of detecting important differences between phosphatic fertilizers is more than sometimes used. It is concluded that extreme reserve is necessary in interpreting trial results which fail to show a significant difference between materials.
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References
Barrow NJ (1985) Comparing the effectiveness of fertilizers. Fert. Res. 8: 85–90
Chien SH, Sale PWG and Friesen DK, (1990) A discussion of the methods for comparing the relative effectiveness of phosphate fertilizers varying in solubility. Fert. Res. 24(3): 149–157
Colwell JD and Goedert WJ (1988) Substitution rates as measures of the relative effectiveness of alternative phosphorus fertilizers. Fert. Res. 15(2): 163–172
Hammond LL, Chien SH and Mokwunye AW (1986) Agronomic value of unacidulated and partially acidulated phosphate rocks indigenous to the tropics. Advances in Agronomy 40: 89–140
Khasawneh FE and Doll EC (1978) The use of phosphate rock for direct application to soils. Advances in Agronomy 30: 159–206
Mullins GL and Sikora FJ (1990) Field evaluation of commercial monoammonium phosphate fertilizers. Fert Res 22: 1–6
Pearson ES and Hartley HO (eds) (1970) Biometricka Tables for Statisticians Volume 1. Cambridge University Press
Sinclair AG and Dyson CB (1988) An interim report on the MAF ‘National Series’ forms of phosphate fertiliser trials. Ministry of Agriculture and Fisheries, PO Box 2526, Wellington, New Zealand
Terman GL, Bouldin DR and Webb JR (1962) Evaluation of fertilizers by biological methods. Advances in Agronomy 14: 265–319
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Johnstone, P.D., Sinclair, A.G. Replication requirements in field experiments for comparing phosphatic fertilizers. Fertilizer Research 29, 329–333 (1991). https://doi.org/10.1007/BF01052402
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DOI: https://doi.org/10.1007/BF01052402