Mineralization of organic phosphorus in soil size fractions under different vegetation covers in the north of Rio de Janeiro

Revista Brasileira de Ciência do Solo

Joice Cleide De Oliveira Rita¹  Antonio Carlos Gama-rodrigues²  Emanuela Forestieri Gama-rodrigues¹  Francisco Costa Zaia¹  Danielle Aparecida Duarte Nunes¹ 

[1] ,UENF Soil Laboratory

关键词: Bowman's extraction method;    leguminous forest tree species;    pasture;    capoeira (secondary forest);    método Bowman;    leguminosas florestais;    pastagem;    capoeira;   

DOI  :  10.1590/S0100-06832013000500010

来源: SciELO

【 摘 要 】

In unfertilized, highly weathered tropical soils, phosphorus (P) availability to plants is dependent on the mineralization of organic P (Po) compounds. The objective of this study was to estimate the mineralization of total and labile Po in soil size fractions of > 2.0, 2.0-0.25 and < 0.25 mm under leguminous forest tree species, pasture and "capoeira" (secondary forest) in the 0-10 cm layer of a Red-Yellow Latosol after 90 d of incubation. The type of vegetation cover, soil incubation time and soil size fractions had a significant effect on total P and labile P (Pi and Po) fraction contents. The total average Po content decreased in soil macroaggregates by 25 and 15 % in the > 2.0 and 2.0-0.25 mm fractions, respectively. In contrast, there was an average increase of 90 % of total Po in microaggregates of < 0.25 mm. Labile Po was significantly reduced by incubation in the > 2.0 (-50 %) and < 0.25 mm (-76 %) fractions, but labile Po increased by 35 % in the 2.0-0.25 mm fraction. The Po fraction relative to total extracted P and total labile P within the soil size fractions varied with the vegetation cover and incubation time. Therefore, the distribution of P fractions (Pi and Po) in the soil size fraction revealed the distinctive ability of the cover species to recycle soil P. Consequently, the potential of Po mineralization varied with the size fraction and vegetation cover. Because Po accounted for most of the total labile P, the P availability to plants was closely related to the mineralization of this P fraction.

【 授权许可】

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