Phosphorus Fertilizer Effects on Soil Phosphorus Pools in Acid Upland Soils

Abstract

Opinions vary on fertilization strategies in part because of uncertainties in methods assessing P supply across sites. We quantified the fate and extractability of fertilizer P after two to four crops with four to five P levels applied to upland rice (Oryza sativa L.)–soybean [Glycine max (L.) Merr.] rotations in three experiments in Asia. Soil P pools were measured by Mehlich‐1 extractant, a modified Hedley fractionation and by mixed‐bed resin capsules after 1 and 14 d (resin adsorption quantity, RAQ‐P1 and RAQ‐P14). Without P addition, 84% of the total P was in the NaOH‐Po and residual‐P fractions across sites. Phosphorus fertilization increased Mehlich‐1 P, resin‐P, NaOH‐Pi, H2SO4‐P, RAQ‐P1, and RAQ‐P14 across sites, whereas NaOH‐Po and residual‐P were unchanged. The sum of resin‐P and NaOH‐Pi increased from 10% to between 20 and 30% of the total soil P. Mehlich‐1 P and resin P increased similarly across sites and fitted quadratic models: the increase in Mehlich‐1 P (mg kg−1 per kg P ha−1) ranged from 0.050 at low P rates to >0.125 at >400 kg P ha−1 The increases per unit P of RAQ‐P, NaOH‐Pi, and H2SO4‐P varied among sites. Oxalate‐extractable Fe accounted for most of the variation in NaOH‐Pi and RAQ‐P. Changes in soil P pools in tropical upland Oxisols and Ultisols following P addition are likely better reflected by NaOH‐Pi and RAQ‐P than Mehlich‐1 P and resin P. Improvements in soil P tests are needed to better discriminate the changes in P pools from fertilization across soils.

Characterizing differences in the phosphorus activation coefficient of three typical cropland soils and the influencing factors under long-term fertilization

“…A further comparison showed that the proportion of labile P pool was much higher in treatments with applied P than in treatments without P, and occluded P pool levels followed the opposite trend (Tables 5 and 6). Our results were consistent with other reports, as Dobermann et al [35] found that the application of P fertilizer mainly increased soluble inorganic P but had little effect on the organic P and residual P fractions. Negassa and Leinweber [11] indicated that long-term cultivation without P fertilizer inputs depleted most of the P fractions, whereas long-term cultivation with P application enriched the P fractions.…”

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 .…”

Applied Manure and Nutrient Chemistry for Sustainable Agriculture and Environment

“…Dobermann et al (2002), found an increase of P i in the resin, NaOH, and H 2 SO 4 fractions due to manure application. Poultry litter applications have not only created P crises in soils, but have also lead to a shift in P fractions.…”

“…These enzymes in the environment are derived from plants and microorganisms and are known to hydrolyze a variety of P compounds . The advantages for the initially large P applications do not only lead to P deficiency corrections for crops, but also affect soil pH, CEC, organic matter content, and biological activities Dobermann et al 2002;Acosta-Martinez and Harmel 2006). Alkaline and acid phosphatases degrade orthophosphate monoesters, operating at alkaline and acid pH, respectively.…”