The Influence of Crop Selection and Soil Properties on the Accumulation and Stabilization of Microbial Residues in Soil
EMSL Project ID
49730
Abstract
The proposed research confronts the emerging paradigm that dead microbial cells, or necromass, are a
major source of organic carbon in soil. Microbial necromass accumulation may vary between annual and
perennial crops, if lower root inputs in annual plants limit substrates that support microbial biomass and
in turn necromass. When complexed on mineral surfaces, microbial necromass may no longer be
bioavailable, contributing to the sequestered C pool.
• Objective 1: Identify the microbial functions (genes, enzymes, metabolites) and components of
microbial necromass (amino sugars, lipids, proteins, carbohydrates) that contribute to soil C
accumulation under controlled conditions. Hypothesis:Undercontrolled conditions,given equalinputsof
13C-labeledmicrobial necromass, decomposition of microbial necromass will be slower in annual
(corn) soils compared to perennial (switchgrass) soils due to smaller microbial biomass and a less
diverse microbiome; after a 1-year incubation, accumulation of microbial necromass (reflecting
longer residence times) will be greater in silty soils compared to sandy soils due to greater abundance
of mineral surfaces.
• Objective 2: Characterize microbial necromass accumulation in response to crop selection and edaphic
factors in situ
Hypothesis:The quantity and rate of soi lorganic C accumulation will be greater in clay and silt
loams, compared to sandy loams.
Hypothesis:Corn (annual)and switchgrass (perennial) soils wil lhave distinct metabolic profiles due to
differences in the metabolites produced by each root-microbiome. This will result in greater
abundance and diversity of soil organic C molecules under switchgrass compared to corn plants
grown in the same soil.
• Objective 3: Generate long-term, cross-site data that can be used to model C cycling in bioenergy
cropping systems under different soil conditions.
Project Details
Start Date
2017-02-20
End Date
2017-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members