Effects of native leaf litter amendments on phosphorus mineralization in temperate floodplain soils

Mary R. Arenberg, Yuji Arai

Research output: Contribution to journalArticlepeer-review

Abstract

As phosphorus (P) losses from Midwestern crop fields degrade water quality in downstream water bodies, the assessment of natural P immobilization in floodplain soils is imperative to reduce P input to the Gulf of Mexico. While the organic C:P ratio of soil is widely accepted as an important indicator of P immobilization, roles of the quality/type of C sources (i.e., foliar C composition and degradability) on soil P dynamics are not clearly understood. The objective of this laboratory incubation study was to assess the influence of leaf residue of native trees (e.g., hackberry, and silver maple) on P reaction dynamics in floodplain soils as a function of C composition (i.e., carbonyl-, alkyl- and aromatic-C) and soil organic C:P ratios. Conventional wet chemical analyses and 31P NMR spectroscopy were used to understand changes in P speciation and phosphatase activities. During the incubation, at a soil organic C:P of ∼200, residues with low aromaticity promoted P mineralization, as evidenced by a sustained increase in labile inorganic P and decrease in microbial P. Conversely, residues with high aromaticity and hydrophobicity (i.e., silver maple) caused a decrease in labile inorganic P and increase in microbial P under the same soil organic C:P, indicating the dominance of P immobilization. At a soil organic C:P of 300, both sugar maple and silver maple promoted P immobilization. Mineralization rates were of lesser magnitude in the soils amended with silver maple, which interestingly contained the largest proportions of recalcitrant C and the highest ratios of aromaticity and hydrophobicity.

Original languageEnglish (US)
Article number129210
JournalChemosphere
Volume266
DOIs
StatePublished - Mar 2021

Keywords

  • Carbon
  • Immobilization
  • Mineralization
  • P NMR spectroscopy
  • Phosphorus

ASJC Scopus subject areas

  • Environmental Engineering
  • Chemistry(all)
  • Environmental Chemistry
  • Pollution
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

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