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Phosphorus Availability in an Oxisol Amended with Biosolids in a Long‐Term Field Experiment
Author(s) -
Alleoni Luis Reynaldo F.,
Fernandes Antonio R.,
Jordão Camila B.
Publication year - 2012
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2011.0113
Subject(s) - biosolids , oxisol , soil water , environmental science , sewage sludge , cation exchange capacity , phosphorus , agronomy , chemistry , field experiment , environmental chemistry , zoology , soil science , environmental engineering , sewage , biology , organic chemistry
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 −1 ) 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 resin method yielded the highest correlation with P contents in leaves and grains.