|Support type:||Scholarships in Brazil - Doctorate|
|Effective date (Start):||November 01, 2015|
|Effective date (End):||October 31, 2017|
|Field of knowledge:||Agronomical Sciences - Agronomy - Soil Science|
|Principal researcher:||Mara Cristina Pessôa da Cruz|
|Grantee:||Lucas Boscov Braos|
|Home Institution:||Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil|
The knowledge of the P fractions and its relations to the available P in tropical regions soils fertilized with organic wastes may improve the fertilizer recommendations and result in a more efficient use of the mineral reserves existent. The aim is to evaluate the organic (Po) and inorganic (Pi) P forms in soil treated with filter cake, diary manure and triple super phosphate and establish relations with the plant available P in function of time. It will be carried out a greenhouse trial, utilizing two soil, three fertilizers (filter cake, diary manure and super triple phosphate) in two application rates and four incubation times. The factors will be combined in a factorial scheme (2x4x2x4), all random with four replications. The rates will be 0 and 100 mg dm-3 of P, calculated, in the case of organic wastes, based on the total P. The incubation times will be 15, 45, 90 and 180 days. In the soil treated with the fertilizers, before the incubation, it will be conducted an experiment to determine the P absorbed by maize plants (P abs) and, in the soil samples, it will be determined the pH, total and dissolved organic C, total P, organic P, resin P and P forms by nuclear magnetic resonance (NMR) of 31P solution and by two fractionation schemes, one for Pi and the other for Po. The analysis of the data will be evaluated at most three factors at a time, in combinations that have the most interesting to explain the results. Data will be submitted to analysis of variance and regression (F test) to evaluate the effects of time in each fraction of P and P uptake by plants. Differences arising from each soil or compost each phosphate in the evaluated variables were compared by Tukey test at 5% probability.