Phosphorus pools in bulk soil and aggregates of differently textured oxisols under different land-use systems in the Brazilian cerrados
Lilienfein, Juliane
Phosphorus pools in bulk soil and aggregates of differently textured oxisols under different land-use systems in the Brazilian cerrados - p. 159-172
This study assessed the influence of land use (continuous cropping, CC; tree plantations, F; pasture, PG; and native savanna, NS) on P concentrations and partitioning in bulk soil and two aggregate size fractions of two Oxisols, one loamy and one clayey. The quantity and quality of physically protected P within aggregates were also determined. Total P in bulk soil and macroaggregates (0.25-2 mm and 2-8 mm) was partitioned into inorganic and organic P fractions (P, and P., respectively) after sequential extraction, using NaHCO, (Olsen), NaOH, HCl, and H2SO4 (residual). Additionally, P binding was examined with 31P nuclear magnetic resonance spectroscopy. Total P concentrations were 70-170 mg/kg in the loamy and 300-450 mg/kg in the clayey soil. The largest P fraction was the NaOH-soluble P (33%-55% of total P concentration). The proportion of easily extractable P was higher in the loamy than in the clayey soil. Because of fertilization, CC and F had higher total and, particularly, higher easily available P concentrations than NS and PG. In the loamy soil, Pi and, in the clayey soil, both Pi and P., were higher in CC and F than in NS and PG. In the loamy soil, P concentrations in macroaggregates (>2 mm) were higher than in bulk soil. Higher monoester P proportions within the large macroaggregates in unplowed systems indicated older intra-aggregate soil organic matter than at the aggregate surfaces. In the plowed system, the monoester/diester ratio was not different between bulk soil and aggregate fractions, indicating faster aggregate turnover.
Savannas
Land use
Sabanas
Oxisols
Particle size
Phosphorus
Brazil
Brasil
Utilización de la tierra
Oxisoles
Tamaño de la partícula
Fósforo
Cerrados CIAT Editor Book chapters Capítulos de libros Química y física del suelo Cerrados Soil chemistry and physics Book chapters
S 623 .S977
Phosphorus pools in bulk soil and aggregates of differently textured oxisols under different land-use systems in the Brazilian cerrados - p. 159-172
This study assessed the influence of land use (continuous cropping, CC; tree plantations, F; pasture, PG; and native savanna, NS) on P concentrations and partitioning in bulk soil and two aggregate size fractions of two Oxisols, one loamy and one clayey. The quantity and quality of physically protected P within aggregates were also determined. Total P in bulk soil and macroaggregates (0.25-2 mm and 2-8 mm) was partitioned into inorganic and organic P fractions (P, and P., respectively) after sequential extraction, using NaHCO, (Olsen), NaOH, HCl, and H2SO4 (residual). Additionally, P binding was examined with 31P nuclear magnetic resonance spectroscopy. Total P concentrations were 70-170 mg/kg in the loamy and 300-450 mg/kg in the clayey soil. The largest P fraction was the NaOH-soluble P (33%-55% of total P concentration). The proportion of easily extractable P was higher in the loamy than in the clayey soil. Because of fertilization, CC and F had higher total and, particularly, higher easily available P concentrations than NS and PG. In the loamy soil, Pi and, in the clayey soil, both Pi and P., were higher in CC and F than in NS and PG. In the loamy soil, P concentrations in macroaggregates (>2 mm) were higher than in bulk soil. Higher monoester P proportions within the large macroaggregates in unplowed systems indicated older intra-aggregate soil organic matter than at the aggregate surfaces. In the plowed system, the monoester/diester ratio was not different between bulk soil and aggregate fractions, indicating faster aggregate turnover.
Savannas
Land use
Sabanas
Oxisols
Particle size
Phosphorus
Brazil
Brasil
Utilización de la tierra
Oxisoles
Tamaño de la partícula
Fósforo
Cerrados CIAT Editor Book chapters Capítulos de libros Química y física del suelo Cerrados Soil chemistry and physics Book chapters
S 623 .S977