The influence of soil microbial community structure on carbon and nitrogen partitioning in plant/soil ecosystems
- Published
- Accepted
- Subject Areas
- Agricultural Science, Soil Science
- Keywords
- soil microbial community, F:B ratio, carbon and nitrogen partitioning, microbial influenced soil respiration
- Copyright
- © 2017 Johnson
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2017. The influence of soil microbial community structure on carbon and nitrogen partitioning in plant/soil ecosystems. PeerJ Preprints 5:e2841v1 https://doi.org/10.7287/peerj.preprints.2841v1
Abstract
A greenhouse study was conducted to evaluate the influence of increasing soil fungal-to-bacterial ratios (F:B) on the allocation of plant-photosynthate carbon into the carbon (C) and nitrogen (N) partitions (g) of plant components (root, shoot and fruit), New-Soil C and N, and Soil-Respiration C (CO2). Six (6) experimental treatment soils were formulated to provide linearly increasing: initial-soil C% (0.14% – 5.3%); initial-soil N% (0.01% - 0.40%); and soil microbial community (SMC) populations progressing from bacterial dominant (F:B=0.04) to fungal dominant (F:B=3.68) while still maintaining significant SMC population homogeneity. In an 86-day greenhouse experiment, growing chile plants (Capsicum annuum) in treatment soils with increasing F:B (0.4-3.68), the following was observed: a) a continuous linear increase (3% up to 56%) in the partitioning of total plant-photosynthate C into plant biomass (root, shoot and fruit) when regressed to initial F:B (m=0.13; r2=0.96); b) approximately 93% of the flow of plant-photosynthate C was partitioned into New-Soil C in Treatment 0 (F:B = 0.04), to a minimum of 47% in Treatment 5 (F:B = 3.68) demonstrating a negative linear correlation to treatment Initial-Soil C mass (m= -0.12; r2 = 0.97); c) conditional and coordinated flow of system C resources into nitrogen (N) fixation (est. C cost for N fixation at 6:1), with 1.21 g C partitioned to N fixation in Treatment 0 (F:B=0.04), peaking at 6.92 g C in Treatment 2 (F:B=1.6), and final C partitioning to N fixation of 2.91 g C in Treatment 5 (F:B=3.68), following a 3rd order polynomial trendline (r2=0.99) when correlated with initial treatment soil C mass; d) decreases in soil respiration, from 44% of Initial-Soil C substrate respired in bacterial-dominant low-C (0.14%) soils (F:B = 0.04) to 11% in fungal dominant (F:B = 3.68), high-C percent (5.30% C) soils (y = -0.108ln(x)+ 0.4987; r2= 0.95). Increasing the F:B in the soils of agroecosystems may provide more efficient accumulation and partitioning of photosynthate C into plant and soil biomass, improved N fixation and beneficial increases in total carbon use efficiencies. Collectively, these benefits could provide a practical and cost-effective path towards: improving crop production, reducing N-fertilizer inputs, promoting a more sustainable agricultural system, while providing a cost-effective approach for capturing and storing atmospheric carbon (CO2) in soils of agroecosystems.
Author Comment
This is a submission to PeerJ for review.