Phosphorus fractions in soil amended with organic and inorganic phosphorus sources

Abstract

. 2004. Phosphorus fractions in soil amended with organic and inorganic phosphorus sources. Can. J. Soil Sci. 84: 83-90. Information on the P fractions in soils treated with different organic amendments is needed to better manage land application of organic amendments to agricultural soils. This study investigated the forms and distribution of P after 1, 4 and 16 wk in a Lakeland silty clay loam soil using a sequential fractionation procedure. Phosphorus was added at rates of 0, 123, 307 and 614 mg P kg -1 in the form of biosolids, hog manure, cattle manure and fertilizer P. The largest difference among the amendments was in the water-extractable P fraction, which was significantly lower in soil amended with biosolids. Regression analysis showed that the slope of P increment in the H 2 O fraction as a function of P application rate was four times lower for biosolids (0.06) than for hog manure (0.24) and seven times lower than for fertilizer (0.42) amended soils. In the biosolids-amended soil, there was a net increase of H 2 O-P, NaOH-Pi and HCl-P fractions at the expense of organic P (NaOH-Po) and residual P fractions after 16 wk of incubation, signifying net P mineralization. In hog manure amended soil, H 2 O-P decreased by 128 mg kg -1 with a corresponding increase in the NaHCO 3 -P, possibly due to P sorption during the 16 wk of incubation. The results for cattle manure indicated net immobilization of P as the H 2 O-P and NaHCO 3 -P declined while the inorganic P (NaOHPi), HCl-P and residual P increased with incubation time. The transformation of P in fertilizer-amended soil was similar to that of hog manure amended soil. The amount of labile P (defined as H 2 O-P plus NaHCO 3 -P) in amended soils followed the order of fertilizer P > hog manure > cattle manure > biosolids. La principale distinction entre ces amendements se rapporte à la fraction de P extractible dans l'eau, qui est nettement plus faible dans les sols bonifiés avec les solides biologiques. Selon l'analyse de régression, la hausse de la concentration de P dans la fraction aqueuse en fonction du taux d'application de P a une pente quatre fois plus faible dans les sols amendés avec des solides biologiques (0,06) que dans ceux fertilisés avec du purin (0,24) et sept fois plus faible que dans ceux bonifiés avec de l'engrais (0,42). Après 16 semaines d'incubation, on remarque une nette hausse des fractions P-H 2 O, Pi-NaOH et P-HCl au détriment du P organique (Po-NaOH) et du P résiduel dans les sols amendés avec les solides biologiques, signe qu'il y a une forte minéralisation du P. Dans le sol amendé avec du purin, la fraction aqueuse diminue de 128 mg de P par kilo tandis que la fraction P-NaHCO 3 connaît une hausse correspondante, sans doute à cause de l'adsorption du P pendant les 16 semaines d'incubation. Les résultats obtenus avec le fumier de bovin indiquent une nette immobilisation du P, car on assiste à une diminution des fractions P-H 2 O et P-NaHCO 3 alors que le P inorganique (Pi-NaOH), le P-HCl et le P résidu-el s'accroissent avec la du...

Organic Phosphorus Fractions in Soil Fertilized With Cattle Manure

“…In this fraction, humic and fulvic acids are the main constituents and the fulvic acids are more labile compounds and contain higher P concentrations (Ivanoff et al, 1998;Schroeder and Kovar, 2006). Finally, the residual fraction might act as P sink in systems treated with P, mainly with fertilizers or residues (Ivanoff et al, 1998;Kashem et al, 2004;Hao et al, 2008). Thus, soils fertilized with excess P, mainly as organic fertilizers, tend to accumulate non-labile P, as occurred in plots treated with manure in this work (Table 3).…”

“…In a soil incubation trial in laboratory, the application of swine manure caused an initial increase of water-soluble P concentrations, but after 16 weeks of incubation, water soluble P decreased with simultaneous increase of the P-NaHCO 3 fraction. Moreover, the application of cattle manure decreased soluble P, while other more stable P forms increased, suggesting that microorganisms transformed labile-Pi into Po, due to the higher amount of grass residues and higher C/P ratio in the manure (Kashem et al, 2004).…”

Evaluating phosphorus loading from repeated manure applications to two Saskatchewansoils

“…However, STP measurements indicated that less than or equal to 120 kg ha Á1 of labile P was present in the soil. Over time, transformation of labile P into non-labile fractions occurs through soil sorption processes, and highly labile, water extractable P fractions are gradually converted into less labile NaHCO 3 and NaOH extractable inorganic P. Results from Manitoba also showed that under SCM application, microbial uptake of labile P occurred, because it contained a high straw content that promoted P immobilization (Kashem et al 2004). Soil sorption and uptake by microbial processes reduces the measurable labile P fraction, and does not provide a quantitative estimate of the total P soil loading rate.…”

Effect of Organic and Inorganic Amendments on the Phytoavailability of Phosphorus to Corn (<i>Zea mays</i>)

“…The availability of city wastes, cow and chicken manures P to crops and its impact on soil P pool may differ from that of inorganic P fertilizer [6][7][8]. McCoy et al [8] found that biosolids (treated City wastes) P was four to seven times less available than triple super phosphate P. In contrast, other studies have suggested that P in organic amendments may be equally or more available than fertilizer P [9,10].…”