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Influence of Organic Matter Decomposition on Soluble Carbon and Its Copper‐Binding Capacity
Author(s) -
Merritt Karen A.,
Erich M. Susan
Publication year - 2003
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2003.2122
Subject(s) - chemistry , humus , incubation , ultrafiltration (renal) , dissolved organic carbon , soil water , organic matter , copper , environmental chemistry , chromatography , organic chemistry , biochemistry , environmental science , soil science
ABSTRACT Bulk and low molecular weight (LMW) (<1 kDa) water‐extractable carbon were collected from fresh and microbially degraded wheat straw ( Triticum aestivum L.) and crimson clover ( Trifolium incarnatum L.) residues to monitor early‐stage humification over an 8‐wk incubation. Copper complexation parameters were determined for both bulk and LMW water‐extractable C for both plant materials in a separate 1‐wk incubation. Humification progressed through increasing molar absorptivity ( A 285 ) and phenolic and total acidity (TA), and through an increase in average molecular size and degree of polymerization as determined by ultrafiltration and changes in fluorescence peak locations. Such dynamic transformations demonstrate that while humification is a bulk property, with C breakdown and stabilization occurring simultaneously and continuously in soil, its early stages can be effectively monitored for fresh plant residues. Significant changes consistently occurred during the first 7 d of the incubation and were more pronounced for LMW fractions than bulk extracts. For both residues, water‐extractable C extracted initially and following a 7‐d incubation desorbed and complexed 0.11 to 0.55 mmol resin‐bound Cu g −1 C. Low molecular weight water‐extractable C generated the higher values within this range, and values increased consistently following incubation. Potential concerns regarding LMW soluble Cu complexes include percolation through soils or runoff into adjacent water bodies as well as effects on plant root development.