Phosphorus Availability in an Oxisol Amended with Biosolids in a Long-Term Field Experiment

Abstract

Many extractors are used to quantify available P in soils, but few studies have assessed the availability of P in soils of the wet tropics amended with high rates of biosolids. In this study, ion exchange resin, Mehlich-1 solution, and Fe-impregnated strips were used to quantify available P in samples from an Oxisol amended with surface-applied biosolids in a long-term field experiment. The soil's maximum capacity for P adsorption was also estimated. Experimental design consisted of randomized blocks, with four treatments and three replicates. Samples of biosolids were collected every year during the experiment, from 1999 to 2002. In 1999, two applications were made before growing maize (Zea mays L.) in austral summer and winter. Treatments were: Control (no biosolids added); B (biosolids added at rates based on their total N content); B2 (biosolids added at twice the rate of B), and B4 (biosolids added at four times the rate of B). Soil samples were collected at 0-to 0.1-, 0.1-to 0.2-, and 0.2-to 0.4-m depths. Biosolids were broadcast applied and incorporated into the soil to a depth of 0.2 m using a rotary hoe. The Oxisol had a high P-adsorption capacity (around 2450 mg kg'') because of its high contents of clay and Fe and Al oxides. All the extractors were effective at assessing P availability and were positively correlated among themselves. Available P soil contents correlated positively with P content in maize leaves and grains, and the rssin method yielded the highest correlation with P contents in leaves and grains.

Phosphorus sorption on tropical soils with relevance to Earth system model needs

“…Although some studies have found that Al plays a more significant role than Fe in P sorption mechanics for both temperate soils (Lopez-Hernandez and Burnham 1974;Sakadevan and Bavor 1998;Börling et al 2001) and tropical soils (Fontes and Weed 1996;Poudel and West 1999;Hartono et al 2005;Gichangi et al 2008;Alleoni et al 2012;Chimdi et al 2013;de Campos et al 2016), our study found that DCB-extracted Al-and Fe-oxides were similarly correlated with the P Qmax values (r = 0.470 and 0.461 respectively). Considering the low R 2 values for these parameters in describing P Qmax, this lack of discrepancy in parameter influence is not surprising.…”

“…The high weathering rate of tropical soils leads to an abundance of clay minerals, providing a high surface area and numerous binding sites (McGechan and Lewis 2002). For ESMs, this provides evidence that information about clay content could significantly aid in the estimation of P sorption parameters for tropical soils (Lopez-Hernandez and Burnham 1974;McGroddy et al 2008;Bruland and DeMent 2009;Moazed et al 2010;Alleoni et al 2012). Although P sorption isotherms are not often performed in routine soil analyses, particle size is a frequently measured parameter.…”

“…Studies that used a maximum P concentration comparable to or exceeding our own also found higher P Qmax values. Alleoni et al (2012) used an initial maximum P concentration of 1200 mg P L À1 for P sorption isotherms in Brazilian Oxisols, and their resulting P Qmax ranged from 2400 to 2600 mg PO 4 -P kg À1 . Poudel and West (1999) analysed tropical volcanic Oxisols, Ultisols, and Inceptisols from the Philippines using initial maximum P concentration of 1000 mg P L À1 and found a mean P Qmax of 12 856 mg PO 4 -P kg À1 .…”

Soil Chemistry Aspects of Predicting Future Phosphorus Requirements in Sub‐Saharan Africa

“…This characterizes the kinetic relationship between the labile and stable pools. The vdZ‐vR model was successfully applied to the Brazilian tropical soils similar to those of SSA (Alleoni et al, ; de Campos et al, ), across a range of pH‐values (Andersson et al, ; do Carmo Horta et al, ; do Carmo Horta & Torrent, ; Freese et al, ; House et al, ; Maguire et al, ); all of which were within the range of SSA soils (Hengl et al, ). vdZ‐vR (Freese et al, ; van der Zee & van Riemsdijk, ) states that the concentration of the stable pool controlled by the chemical kinetics ( S c , kg · ha −1 ) is proportional to the size of weathered (amorphous, oxalate‐extractable) Fe and Al oxide concentrations and the size of the labile pool.…”

Mineralization and mobilization of biosolids phosphorus in soil: A concise review

“…The optimum pH for P availability to crops in the soil is between 6 and 7 [75]. Lowering soil pH (4.5-5.1) causes decreased soil microbial activities and can lead to subsequent changes in the substrate utilization [76,77].…”