Phosphorus fractions of soils under Lotus corniculatus as affected by different phosphorus fertilizers

Phosphorus fractions in sandy soils of vineyards in southern Brazil

“…This can probably be attributed to P transformation into more stable forms, not accessed by these extractors, as well as by P migration to deeper soil layers, especially because the soils have a sandy texture and low Fe oxide content (Table 1). It is also worth mentioning that the results of soil P extracted by anion-exchange resin and by 0.5 mol L -1 NaHCO 3 are similar to results published in other studies (Herlihy & McGrath, 2007;Boschetti et al, 2009;Tokura et al, 2011) which also used P chemical fractionation and reported that the contents of these two fractions increase with the dose of soluble phosphate fertilizers applied over time. It should also be mentioned that the P contents extracted by anionexchange resin in the 0-5 cm layer of both vineyards were considered high (> 20 mg kg -1 ) (CQFSRS/SC, 2004).…”

“…The organic P contents extracted by 0.5 mol L -1 NaOH were higher in the 0-5 and 11-20 cm layers in vineyard 2 as compared to the soil of vineyard 1 and native grasslands. These higher organic P contents extracted by 0.1 mol L -1 NaOH and organic P extracted by 0.5 mol L -1 NaOH in both vineyard soils may be associated with successive deposition of crop litter on the soil surface, both in vineyard 1 and vineyard 2, especially in the latter, cultivated for 30 years, compared to the 14 years of vineyard 1 (Boschetti et al, 2009). …”

Accumulation of phosphorus fractions and contamination potential in vineyard soils in the southern region of the state of Santa Catarina, Brazil

“…Therefore, the amount of P fertilized before planting and during cultivation exceeded the soil and vine requirements, and could be one of the reasons for the high levels of inorganic P extracted from the vineyard soils by AER and inorganic P extracted by 0.5 mol L -1 NaHCO 3 , particularly from vineyard 2. The data of inorganic P extracted by AER and inorganic P extracted by 0.5 mol L -1 NaHCO 3 in the soil agree with data published elsewhere (Oberson et al, 1999;Dobermann et al, 2002;Zhang et al, 2004;Herlihy & McGrath, 2007;Boschetti et al, 2009;Tokura et al, 2011); these studies also used the technique of P chemical fractionation and reported that the level of the two nutrient fractions in the soil would increase with the applied rate of soluble phosphate fertilizers and would tend to be higher than other fractions removed by other extractants during fractionation. This may be attributed to the greater quantity of P applied in relation to the quantity extracted by the plants, causing P accumulation in different fractions, including in labile fractions extracted by AER and inorganic P extracted by 0.5 mol L -1 NaHCO 3 .…”

“…Greater organic P contents extracted by 0.1 mol L -1 NaOH in all soil layers were found in vineyard 2, compared to the vineyard 1 soil. This may be due to organic matter buildup on the soil surface and in the surface layer, by plant roots and also residues of the above-ground part of some species of plant cover (Boschetti et al, 2009;Brunetto et al, 2009Brunetto et al, , 2011, as well as with branches and dead leaves fallen from vines, and the renewal of their roots (Brunetto et al, 2009(Brunetto et al, , 2011. The inorganic P content extracted by 0.5 mol L -1 NaOH in vineyards 1 and 2 tended to be greater in the 0-5 cm layer, but was similar in the same soil layer of both vineyards.…”

“…In general, the buildup is greater in the inorganic fractions Boschetti et al, 2009;Santos et al, 2008;Pavinato et al, 2009;Tokura et al, 2011). Phosphorus adsorption occurs initially at the most avid sites and with a greater binding strength, and then the remaining P is redistributed in lower energy fractions (Rheinheimer & Anghinoni, 2001).…”