Agronomic efficiency of granulated organomineral fertilizers based on poultry litter and phosphates.

This paper has as aim to evaluate the agronomic efficiency of granulated organomineral fertilizers produced from poultry litter and mineral sources of phosphorus

Soil organic matter and fertility of anthropogenic dark earths (Terra Preta de Índio) in the Brazilian Amazon basin.

The Brazilian Amazon basin in soil organic matter and fertility of anthropogenic dark earths (Terra Preta de Índio)

Soil organic matter and fertility of anthropogenic dark earths (Terra Preta de Índio) in the Brazilian Amazon basin.

Propriedades de fertilidade, carbono total (Ctot) e frações químicas da matéria orgânica (fração ácidos fúlvicos - FA, fração ácidos húmicos - HA e fração humina - HUM) foram comparados entre solos antrópicos (Terra Preta de Índio) e Latossolos sem horizonte A antrópico. Os solos antrópicos apresentaram maior fertilidade (pH: 5,1-5,4; S: 8,93-10,33 cmolc kg-1; CEC: 17,2-17,5 cmolc kg-1; V: 51-59 %; P: 116-291 mg kg-1) e maiores teores de carbono total (44,6-44,7 g kg-1) que os Latossolos (pH: 4,4; S: 2,04 cmolc kg-1; CEC: 9,5 cmolc kg-1; V: 21 %, P: 5 mg kg-1, Ctot: 37,9 g kg-1). Os solos antrópicos também tiveram distribuição diferenciada de C entre as frações das substâncias húmicas (FA, HÁ e HUM), expressa pelas razões HA:FA e EA:HUM (EA = HA + FA), que foram de 2,1-3,0 e 1,06-1,08 para as Terras Pretas de Índio e de 1,2 e 0,72 para Latossolos, respectivamente. Enquanto a capacidade de troca catiônica (CTC) de Latossolos apresentou correlação com a fração FA (r = 0,97), a CTC das Terras Pretas de Índio correlacionou-se com a fração HUM (r = 0,82). Essa correlação entre a fertilidade das Terras Pretas de Índio e a fração mais estável das substâncias húmicas (HUM) tem importantes implicações no desenvolvimento de modelos sustentáveis de manejo da fertilidade de solos em ecossistemas tropicais

Analyzing the mobility in granular forms of P fertilizer in brazilians soils under laboratory conditions.

Phosphorus is an essential nutrient for plant growth. Million of tones of P are applied to the soils annually. However, only a small fraction of the P applied with fertilizers is taken up by crops in the year of application, and the effectiveness of any residual P fertilizer declines with time. To improve our understanding of the mechanisms underlying this response to P in the field, we have studied the mobility of P from 3 different fertilizes: monoammonium phosphate (MAP), polymer coated monoammonium phosphate (MAPp) and Organomineral phosphate (OMP) applied on high weathered soil samples in a Petri dish experiment. Total Reflection X-Ray Fluorescence (TXRF) was used to determine the P diffusive flux at different distances (0 - 7.5, 7.5 ? 13.5, 13.5 ? 25.5 and 25.5 ? 43 mm) from granular fertilizer. TXRF analyses were performed at the X-Ray Fluorescence Beamline D09B at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, São Paulo, using a polychromatic beam with maximum energy of 20 keV for the excitation and an Ultra-LEGe detector with resolution of 148 eV at 5.9 keV. Besides that, the detections were performed in a high vacuum chamber (2.5 x 10-5 mbar) to avoid air absorption. After a period of five weeks, the total P concentration increased in the soil sampled 7.5 to 13.5 mm from the fertilizer showing a diffusive flux of P. About 20% (considering MAP and MAPp) of the total P applied diffused out of the central soil ring. Different sources showed differences in diffusive flux of P. Soil pH also influenced diffusive flux of P showing higher flux on lower pH soils