TY - JOUR
T1 - A novel biologically-based approach to evaluating soil phosphorus availability across complex landscapes
AU - DeLuca, Thomas H.
AU - Glanville, Helen C.
AU - Harris, Matthew
AU - Emmett, Bridget A.
AU - Pingree, Melissa R.A.
AU - de Sosa, Laura L.
AU - Morenà, Cristina
AU - Jones, Davey L.
PY - 2015/9/1
Y1 - 2015/9/1
N2 - 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 non-agricultural 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.
AB - 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 non-agricultural 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.
KW - Bioavailability
KW - Ecosystem assessment
KW - Nutrient index
KW - Phosphate
KW - Soil quality indicator
UR - http://www.scopus.com/inward/record.url?scp=84930675423&partnerID=8YFLogxK
U2 - 10.1016/j.soilbio.2015.05.016
DO - 10.1016/j.soilbio.2015.05.016
M3 - Article
AN - SCOPUS:84930675423
SN - 0038-0717
VL - 88
SP - 110
EP - 119
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
ER -