Plants employ a range of strategies to increase phosphorus (P) availability in soil. Current soil... more Plants employ a range of strategies to increase phosphorus (P) availability in soil. Current soil P extraction methods (e.g. Olsen P), however, often fail to capture the potential importance of rhizosphere processes in supplying P to the plant. This has led to criticism of these standard approaches, especially in nonagricultural soils of low P status and when comparing soil types across diverse landscapes. Similarly, more complex soil P extraction protocols (e.g. Hedley sequential fractionation) lack functional significance from a plant ecology perspective. In response to this, we present a novel procedure using a suite of established extraction protocols to explore the concept of a protocol that characterizes P pools available via plant and microbial P acquisition mechanisms. The biologically based P (BBP) extraction was conducted by using four extractions in parallel: (1) 10 mM CaCl2 (soluble P); (2) 10 mM citric acid (chelate extractable P); (3) phytase and phosphatase solution (enzyme extractable organic P); (4) 1 M HCl (mineral occluded P). To test the protocol, we conducted the analyses on a total of 204 soil samples collected as part of a UK national ecosystem survey (Countryside Survey) in 1998 and repeated again in 2007. In the survey, Olsen P showed a net decline in national soil P levels during this 10 year period. In agreement with these results, soluble P, citrate extractable P and mineral occluded P were all found to decrease over the 10 year study period. In contrast, enzyme extractable organic P increased over the same period likely due to the accumulation of organic P in the mineral soil. The method illustrates a noted shift in P pools over the 10 year period, but no net loss of P from the system. This new method is simple and inexpensive and therefore has the potential to greatly improve our ability to characterise and understand changes in soil P status across complex landscapes.
Plants employ a range of strategies to increase phosphorus (P) availability in soil. Current soil... more Plants employ a range of strategies to increase phosphorus (P) availability in soil. Current soil P extraction methods (e.g. Olsen P), however, often fail to capture the potential importance of rhizosphere processes in supplying P to the plant. This has led to criticism of these standard approaches, especially in nonagricultural soils of low P status and when comparing soil types across diverse landscapes. Similarly, more complex soil P extraction protocols (e.g. Hedley sequential fractionation) lack functional significance from a plant ecology perspective. In response to this, we present a novel procedure using a suite of established extraction protocols to explore the concept of a protocol that characterizes P pools available via plant and microbial P acquisition mechanisms. The biologically based P (BBP) extraction was conducted by using four extractions in parallel: (1) 10 mM CaCl2 (soluble P); (2) 10 mM citric acid (chelate extractable P); (3) phytase and phosphatase solution (enzyme extractable organic P); (4) 1 M HCl (mineral occluded P). To test the protocol, we conducted the analyses on a total of 204 soil samples collected as part of a UK national ecosystem survey (Countryside Survey) in 1998 and repeated again in 2007. In the survey, Olsen P showed a net decline in national soil P levels during this 10 year period. In agreement with these results, soluble P, citrate extractable P and mineral occluded P were all found to decrease over the 10 year study period. In contrast, enzyme extractable organic P increased over the same period likely due to the accumulation of organic P in the mineral soil. The method illustrates a noted shift in P pools over the 10 year period, but no net loss of P from the system. This new method is simple and inexpensive and therefore has the potential to greatly improve our ability to characterise and understand changes in soil P status across complex landscapes.
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Papers by Laura Lozano de Sosa
methods (e.g. Olsen P), however, often fail to capture the potential importance of rhizosphere processes
in supplying P to the plant. This has led to criticism of these standard approaches, especially in nonagricultural
soils of low P status and when comparing soil types across diverse landscapes. Similarly,
more complex soil P extraction protocols (e.g. Hedley sequential fractionation) lack functional significance
from a plant ecology perspective. In response to this, we present a novel procedure using a suite of
established extraction protocols to explore the concept of a protocol that characterizes P pools available
via plant and microbial P acquisition mechanisms. The biologically based P (BBP) extraction was conducted
by using four extractions in parallel: (1) 10 mM CaCl2 (soluble P); (2) 10 mM citric acid (chelate
extractable P); (3) phytase and phosphatase solution (enzyme extractable organic P); (4) 1 M HCl
(mineral occluded P). To test the protocol, we conducted the analyses on a total of 204 soil samples
collected as part of a UK national ecosystem survey (Countryside Survey) in 1998 and repeated again in
2007. In the survey, Olsen P showed a net decline in national soil P levels during this 10 year period. In
agreement with these results, soluble P, citrate extractable P and mineral occluded P were all found to
decrease over the 10 year study period. In contrast, enzyme extractable organic P increased over the
same period likely due to the accumulation of organic P in the mineral soil. The method illustrates a
noted shift in P pools over the 10 year period, but no net loss of P from the system. This new method is
simple and inexpensive and therefore has the potential to greatly improve our ability to characterise and
understand changes in soil P status across complex landscapes.
methods (e.g. Olsen P), however, often fail to capture the potential importance of rhizosphere processes
in supplying P to the plant. This has led to criticism of these standard approaches, especially in nonagricultural
soils of low P status and when comparing soil types across diverse landscapes. Similarly,
more complex soil P extraction protocols (e.g. Hedley sequential fractionation) lack functional significance
from a plant ecology perspective. In response to this, we present a novel procedure using a suite of
established extraction protocols to explore the concept of a protocol that characterizes P pools available
via plant and microbial P acquisition mechanisms. The biologically based P (BBP) extraction was conducted
by using four extractions in parallel: (1) 10 mM CaCl2 (soluble P); (2) 10 mM citric acid (chelate
extractable P); (3) phytase and phosphatase solution (enzyme extractable organic P); (4) 1 M HCl
(mineral occluded P). To test the protocol, we conducted the analyses on a total of 204 soil samples
collected as part of a UK national ecosystem survey (Countryside Survey) in 1998 and repeated again in
2007. In the survey, Olsen P showed a net decline in national soil P levels during this 10 year period. In
agreement with these results, soluble P, citrate extractable P and mineral occluded P were all found to
decrease over the 10 year study period. In contrast, enzyme extractable organic P increased over the
same period likely due to the accumulation of organic P in the mineral soil. The method illustrates a
noted shift in P pools over the 10 year period, but no net loss of P from the system. This new method is
simple and inexpensive and therefore has the potential to greatly improve our ability to characterise and
understand changes in soil P status across complex landscapes.