DOI: 10.5061/dryad.tmpg4f559
title: Centennial deforestation impacts on soil phosphorus cycling in the Amazon rainforest

description: Deforestation of tropical rainforests is a major land use change that
 alters terrestrial biogeochemical cycling at local to global scales.
 Deforestation and subsequent reforestation are likely to impact soil
 phosphorus (P) cycling, which in P-limited ecosystems such as in the
 Amazon basin has implications for long-term land use change and
 productivity. We used a 100-year observational chronosequence of primary
 forest conversion to pasture, as well as a 13-year-old secondary forest,
 to test land use change and duration effects on soil P dynamics in the
 Amazon basin. By combining sequential extraction and P K-edge X-ray
 absorption near edge structure (XANES) spectroscopy with soil phosphatase
 assays, we assessed pools and process rates of P cycling in surface soils.
 Deforestation caused increases in total P (135-398 mg kg-1), total organic
 P (Po) (19-168 mg kg-1), and total inorganic P (Pi) (30-113 mg kg-1)
 fractions in surface soils with pasture age, with concomitant increases in
 Pi fractions corroborated by sequential fractionation and XANES
 spectroscopy. Soil non-labile Po (10-148 mg kg-1) increased
 disproportionately compared to labile Po (from 4-5 to 7-13 mg kg-1). Soil
 phosphomonoesterase and phosphodiesterase binding affinity (Km) decreased
 while the specificity constant (Ka) increased by 83-159% in 39–100y
 pastures. Soil P pools and process rates reverted to magnitudes similar to
 primary forests within 13 years of pasture abandonment, though the
 relatively short but representative pre-abandonment pasture duration of
 our secondary forest may not enable significant deforestation effects on
 soil P cycling, highlighting the need to consider both pasture duration
 and reforestation age in evaluations of Amazon land use legacies. Although
 the space-for-time substitution design can entail variation in the initial
 soil P pools due to atmospheric P deposition, soil properties, and/or
 primary forest growth, the trend of P pools and process rates with pasture
 age still provides valuable insights.
description: The methods of this dataset can be found in the related
 article.
description: # Centennial deforestation impacts on soil phosphorus cycling in the
 Amazon rainforest We used
 a 100-year observational chronosequence of primary forest conversion to
 pasture, as well as a 13-year-old secondary forest, to test land use
 change and duration effects on soil P dynamics in the Amazon basin. By
 combining sequential extraction and P K-edge X-ray absorption near edge
 structure (XANES) spectroscopy with soil phosphatase assays, we assessed
 pools and process rates of P cycling in surface soils. ## Description of
 the data and file structure All experiment results are included in the
 uploaded Excel file. Data description can be found in the corresponding
 manuscript once it's published. Basically, the sampling area has
 served as a model for studying forest-to-pasture conversion due to
 staggered times of primary forest conversion to pasture over the last
 century, which enables characterizing long-term changes in soil P cycling
 in the present study. We carefully selected specific plot locations for
 primary and secondary forests as well as pastures on the same soil type,
 Kandiudults (USDA Soil Taxonomy) or red-yellow podzolic Latosols (World
 Reference Base for Soil Resources), with sandy clay loam texture formed on
 parent material of pre-Cambrian granite. ## Description of variables: |
 Variables | Description | | :----------- |
 :---------------------------------------------------------------------------------------------------------------------- | | Soil ID | Each ID stands for the individual soil sample and the location of the sample. | | defor\_year | Deforestation year from 0y (primary forest) to 100y of pasture age. A 13-year of the secondary forest is also included. | | pH | Soil pH measured by adding water to the soil with a ratio of 1:5 (m/v) and incubating for 1 hour | | available\_N | Soil Available nitrogen concentration (mg/kg) | | OM\_g/kg | Soil organic matter content (g/kg) | | M3P | Soil Mehlich III phosphorus (mg/kg) | | OC\_g/kg | Soil organic carbon (g/kg) | | Sand | Percent sand in soil | | Silt | Percent silt in soil | | Clay | Percent clay in soil | | Soil texture | Soil texture class, analyzed based on the sand, silt, and clay contents | | resin\_Pi | Anion exchange membrane extractable inorganic phosphorus in soil (mg/kg), from Hedley fractionation | | H2O\_Po | Water extractable organic phosphorus in soil (mg/kg), from Hedley fractionation | | NaHCO3\_Pi | 0.5M sodium bicarbonate extractable inorganic phosphorus in soil (mg/kg), from Hedley fractionation | | Labile\_Pi | The sum of resin\_Pi and NaHCO3\_Pi (mg/kg), from Hedley fractionation | | NaHCO3\_Po | 0.5M sodium bicarbonate extractable organic phosphorus in soil (mg/kg), from Hedley fractionation | | NaOH\_Pi | 0.1M sodium hydroxide extractable inorganic phosphorus in soil (mg/kg), from Hedley fractionation | | NaOH\_Po | 0.1M sodium hydroxide extractable organic phosphorus in soil (mg/kg), from Hedley fractionation | | HCl\_Pi | 1M hydrochloric acid extractable inorganic phosphorus in soil (mg/kg), from Hedley fractionation | | TIP | The sum of resin\_Pi, NaHCO3\_Pi, NaOH\_Pi, and HCl\_Pi (mg/kg), from Hedley fractionation | | TOP | The sum of H2O\_Po, NaHCO3\_Po, and NaOH\_Po (mg/kg), from Hedley fractionation | | TP | Soil total phosphorus determined by digestion with nitric acid and hydrogen peroxide at 105 °C for 24 h | | XANES\_Fe\_P | Iron associated phosphate in soil (%) determined by Phosphorus K-edge X-ray absorption structure spectroscopic analysis | | :----------- | :-------------------------------------------------------------------------------------------------------------------------- | | XANES\_OP | Organic phosphorus in soil (%) determined by Phosphorus K-edge X-ray absorption structure spectroscopic analysis | | XANES\_Ca\_P | Calcium associated phosphate in soil (%) determined by Phosphorus K-edge X-ray absorption structure spectroscopic analysis | | XANES\_Al\_P | Aluminum associated phosphate in soil (%) determined by Phosphorus K-edge X-ray absorption structure spectroscopic analysis | | PME\_Vm | The maximum catalysis rate of soil phosphomonoesterase (µmol g-1 h-1) | | PME\_Km | The substrate affinity of soil phosphomonoesterase (mmol/g) | | PDE\_Vm | The maximum catalysis rate of soil phosphodiesterase (µmol g-1 h-1) | | PDE\_Km | The substrate affinity of soil phosphodiesterase (mmol/g) | | PME\_Ka | The catalysis efficiency of soil phosphomonoesterase (µmol h-1 mmol-1) | | PDE\_Ka | The catalysis efficiency of soil phosphodiesterase (µmol h-1 mmol-1) | | P\_ox | Oxalate extractable soil phosphorus (mg/kg) | | Fe\_ox | Oxalate extractable soil iron (mg/kg) | | Al\_ox | Oxalate extractable soil aluminum (mg/kg) | | P\_di | Dithonite extractable soil phosphorus (mg/kg) | | Fe\_di | Dithonite extractable soil iron (mg/kg) | | Al\_di | Dithonite extractable soil aluminum (mg/kg) | | SWI | Soil weathering index: Fe_di/(Fe_ox+Fe_di) ratio |