Data/hora: 14/05/2024 04:44:09

Biblioteca(s): | Embrapa Meio-Norte.
Data corrente: | 14/04/2010
Data da última atualização: | 21/06/2022
Autoria: | GALVÃO, S. R. da S.; SALCEDO, I. H.
Afiliação: | Sandra Regina da Silva Galvão, Embrapa Meio-Norte; Ignacio Hernan Salcedo, Universidade Federal de Pernambuco.
Título: | Soil phosphorus fractions in sandy soils amended with cattle manure for long periods.
Ano de publicação: | 2009
Fonte/Imprenta: | Revista Brasileira de Ciência do Solo, Viçosa, MG, v. 33, n. 3, p. 613-622, maio/jun. 2009.
Idioma: | Português
Conteúdo: | Phosphorus fractions were determined in soil samples from areas fertilized or not with farmyard cattle manure (FYM) and in samples of FYM used in the semi-arid region of Paraiba state, Brazil. Soil samples were taken from the 0?20; 20?40 and 40?60 cm layers of 18 cultivated areas, which, according to interviews with farmers, had been treated with 12 to 20 t ha-1 FYM annually, for the past 2 to 40 years. Soil samples were also collected from four unfertilized pasture areas as controls. Phosphorus in the soil samples was sequentially extracted with water (Pw), resin (Pres), NaHCO3 (Pibic and Pobic), NaOH (Pihid and Pohid), H2SO4 (Pacid) and, finally, by digestion with H2SO4/H2O2 (Presd). Nine FYM samples were extracted with water, resin, Mehlich-1, H2SO4, NaOH or digestion with H2SO4/H2O2, not sequentially, and the extracts analyzed for P. The sampled areas had homogeneous, sandy and P-deficient soils; increases in total soil P (Pt) above the mean value of the control areas (up to 274 mg kg-1 in the 0?20 cm layer of the most P-enriched samples) were therefore attributed to FYM applications, which was the only external P input in the region. Regression analysis was used to study the relationship between soil P fractions and Pt. The Pacid fraction, related to Ca-P forms, showed the greatest increases (p < 0.01) as a result of FYM applications, rising from 8.4 mg kg-1 in a non-fertilized sample to 43.8 mg kg-1 in the sample with the highest Pt content. The sum of Pw, Pres and Pibic, considered as labile P, showed comparable increases with Pacid, while Pihid showed the smallest increase due to FYM applications. Organic P forms also increased, more so the fraction Pohid, considered less labile, than the more labile one, Pobic. The residual P fraction was practically half of Pt, independently of the Pt value. Increases in labile P, Pacid and organic P were justified by the high average concentration of Pw (36 %), Pacid (34 %), and Pohid (30 %) in the FYM. Significant changes in the proportion of P forms among soil layers indicated the downward movement of P in organic forms.
Palavras-Chave: | Organic phosphorus; Phosphorus leaching; Water soluble phosphorus.
Categoria do assunto: | --
URL: | http://www.scielo.br/pdf/rbcs/v33n3/v33n3a14.pdf
Registro original: | Embrapa Meio-Norte (CPAMN)
Exemplares: | CPAMN - (24190-1) - UPC - AP - PP - 141/10 -  - 2010.00141 - DIS