Long - term P Fertiliser application increases soil phosphorus (P) labile fractions, which can be associated with crop P uptake and grain yield and are useful to improve fertilizer recommendations. Research aims were to evaluate in long-term experiments with different P Fertiliser application in a Mollisol and a Vertisol: (a) the changes of soil P fractions and (b) the relationship between soil P fractions with long - term P Fertiliser application, with accumulated apparent P budget, grain P, total P uptake, soybean (Glycine max L.Merr.) and maize (Zea mays L.) grain yield. Soil P fractions were measured after 1 and 9 year since the beginning of the long - term experiments.\nExperiments included an initial Fertiliser application rate of 200 kg P ha−1 and annual P Fertiliser application rate of 36 kg P ha−1. Bray1-P, total, organic, and inorganic P in fine (minor to 53 μm) and coarse (minor to 53 μm) (CF) soil fractions, and in NaHCO3 extract were measured. Initial P Fertiliser application increased inorganic and total P fractions. However, Bray1-P,\ntotal P in NaHCO3 extract and in the CF were the fractions that most increased with continuous long-term P Fertiliser application in both sites. In the Mollisol, maize grain yield was unrelated to long-term P Fertiliser application. In the Vertisol, total P in NaHCO3 extract, and total and organic P in the CF were more closely related to soybean grain yield than Bray1-P.\nWe proposed soil P indices of labile inorganic and organic P that showed close relationships with soybean grain yield and may be useful to improve the diagnosis of P soil fertility.
Appelhans, S. C.; Barbagelata, P. A.; Melchiori, R. J. M.; & Gutiérrez Boem, F. H. (2020). Assessing soil P fractions changes with long - term phosphorus fertilization related to crop yield of soybean and maize. Soil use and management,36, (3),p.524-535
Appelhans, Stefania Carolina, Barbagelata, Pedro A., Melchiori, Ricardo José Miguel, Gutiérrez Boem, Flavio Hernán. 2020. "Assessing soil P fractions changes with long - term phosphorus fertilization related to crop yield of soybean and maize". Soil use and management 36, no.3:524-535.
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