Laboratory Characterization of Phosphorus in Fresh and Oven‐Dried Organic Amendments

Abstract

This study was performed to determine the forms of P and to examine the influence of oven-drying on P forms in different organic amendments. Samples of biosolids, beef and dairy cattle manures, and hog manures from sow and nursery barns were used in this study. Both fresh and oven-dried amendments were analyzed for inorganic (Pi), organic (Po), and total phosphorus using a modified Hedley fractionation technique. Water extracted about 10% of total biosolids P and 30 to 40% of total hog and cattle manure P. The amount of P extracted by NaHCO3 ranged from 21 to 32% of total P in all organic amendments except in the dairy cattle manure with 45% of total P. The labile P fraction (sum of H2O- and NaHCO3-extractable P) was 24% of biosolids P, 60% of hog manure P, and 70% of dairy cattle manure P. The residual P was about 10% in biosolids and cattle manures and 5 to 8% in hog manures. Oven-drying caused a transformation in forms of P in the organic amendments. In hog manures, H2O-extractable Po was transformed to Pi, while in the dairy manure NaHCO3-extractable P was converted to H2O-extractable Pi with oven-drying. Therefore, caution should be exercised in using oven-drying for studies that evaluate forms of P in organic amendments. Overall, these results indicate that biosolids P may be less susceptible to loss by water when added to agricultural land.

Soil phosphorus fractions in sandy soils amended with cattle manure for long periods

“…The increase in soil labile P concentrations can be justified by the high P w and P res concentrations in the FYM samples (P w =1.0 and P res =1.2 g kg -1 MS) that represent approximately 36 % of the P t contained in this material (Table 1). It is worth remembering that as the P extraction from the FYM was not sequential, unlike the soil samples, practically all resin extractable P was the water-soluble P. The mean Pw values found by Sharpley & Moyer (2000) in FYM were within the 15-47 % range of P t , while Cassol et al (2001) reached an extraction of 65 % of P t with resin and Ajiboye et al (2004) 40 % of P t with water.…”

Acumulação de nutrientes em solos arenosos adubados com esterco bovino

“…Na maioria das pesquisas que utilizaram esterco bovino, o N apresentou o maior teor (Cassol et al, 2001), mas em alguns casos o teor de Ca foi maior, ou se assemelhou ao teor de N (Sharpley et al, 2004). Além do N, os demais nutrientes no esterco também apresentaram baixos teores (Tabela 2), quando comparados com valores encontrados em outros trabalhos (Cassol et al, 2001;Ajiboye et al, 2004;Sharpley et al, 2004).…”

“…O P disponível nas áreas adubadas aumentou 20 (0-20 cm), 22 (20-40 cm) e 25 vezes (40-60 cm) em relação às não adubadas (Tabela 1), devido ao teor médio elevado de P no esterco utilizado na região (Tabela 2), e ao fato de uma elevada proporção do P no esterco estar em formas disponíveis (Cassol et al, 2001;Ajiboye et al, 2004). A deficiência de P é intensa e generalizada na região.…”

“…Deve-se considerar que a maior parte do P contido no esterco está em formas inorgânicas (P-resina) (Cassol et al, 2001). A contaminação dos lençóis freáticos com P é um tema atual em vários países que utilizam este insumo, uma vez que a dose de esterco a ser aplicada baseia-se na necessidade de N das culturas, o que pode propiciar a adição excessiva de P ao solo (Griffin et al, 2003;Ajiboye et al, 2004;Djodjic et al, 2004).…”

Phosphorus forms in some grassland soils in Wielkopolska region: characterisation and availability for plants

“…The amounts of phosphorus available for plants (P a ) was obtained by procedure described by Sapek and Sapek (1997). Soil samples were subjected to sequential phosphorus fractionation using a modified version of the Hedley et al (1982) procedure as described by Ajiboye et al (2004). Extraction was performed sequentially using deionized water (Fr.…”