Announcements

Job offersmore »

Tweeting Growers

Last commentsmore »

Top 5 - yesterday

  • No news has been published yesterday.

Top 5 - last week

Top 5 - last month

Exchange ratesmore »




UNH research:

Microbial traits, not plants, determine abundance of soil organic matter

Healthy soil is rich in organic matter, but scientists have yet to fully understand exactly how that organic matter is formed. Now a team of University of New Hampshire scientists have uncovered evidence that microbial pathways – not plants – are the chief originator of the organic matter found in stable soil carbon pools.

The new insight provides promise for designing agricultural systems that promote microbial communities to optimize soil organic matter formation.

The research was conducted by Cynthia Kallenbach, former UNH graduate student now at Colorado State University, her advisor, Stuart Grandy, associate professor of natural resources at UNH, and Serita Frey, professor of natural resources at UNH. Their results were published in the paper “Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls” in the journal Nature Communications, and comes from work supported by the NH Agricultural Experiment Station.

In the paper, UNH scientists suggest that soil organic matter accumulates from inputs of dead microbial cells and microbial byproducts formed when microbes eat plant roots and residues, rather than from plants themselves, as previously thought.

In the past, scientists thought the best way to build soil organic matter was to slow down or inhibit decomposition using plants that soil microbes find difficult to decompose. The idea was that the undecomposed plant parts would gradually become soil organic matter, especially if the soil microbial community was inactive.


The progression of the development of soil as organic matter accumulates during the lab experiment.

However, this pool of soil organic matter, decomposing plant parts, doesn’t last long and can quickly disappear as carbon dioxide, sometimes within a year. This left the question: how do we form pools of soil organic matter that persist for decades, and that are so critical for sustaining healthy, productive soils?

Soil organic matter is a massive reservoir of carbon – containing more than twice as much carbon as there is atmospheric carbon dioxide. Thus, even relatively small changes in soil organic matter can have a large impact on atmospheric carbon dioxide, a critical greenhouse gas. Soil organic matter is also fundamental for plant growth and healthy agricultural systems.

"Soil carbon, in my mind, is the fulcrum around which all aspects of soil revolve," Kallenbach said.

The UNH research paints a completely different pathway to building soil organic matter. This has been challenging for scientists to demonstrate, because once soil organic matter is formed, identifying whether it was most recently a plant or microbial cell is impossible.

In the lab, the scientists demonstrated the accumulation of significant amounts of chemically complex, persistent soil organic matter from microbial materials, in the absence of any plant inputs. Microbes unexpectedly produced soil organic matter that was almost identical to natural, field-derived soil organic matter when fed nothing but table sugar. Further, soil organic matter accumulation is greatest when more–not less–active microbial biomass is formed. This is especially true when that biomass is produced more efficiently, meaning more of the substrate is converted to biomass rather than carbon dioxide.

“Cynthia showed that the amount of organic matter formed depends heavily on the characteristics and physiology of the microbial community,” Grandy said. “Challenging another long-held view, Cynthia also found that the characteristics of the microbial community are even more important for soil organic matter formation than soil type.”

This material is based upon work supported by the National Science Foundation Doctoral Dissertation Improvement Grant (DEB-1311501) and the NH Agricultural Experiment Station through joint funding of the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award numbers 1003421 and 1007001, and the state of New Hampshire.

Source: University of New Hampshire

Publication date: 1/6/2017

 


 

Other news in this sector:

12/7/2017 US (OR): Researchers model optimal amount of rainfall for plants
12/1/2017 "Bio-fertilization works in pelargonium"
11/24/2017 AkzoNobel breaks ground for European micronutrients expansion project
11/20/2017 Floriculture nutrition: The latest in phosphorus fertility
11/17/2017 Growth response of herbaceous ornamentals to phosphorus fertilization
10/24/2017 CAN (ON): Vineland contributes soil knowledge to tree-planting effort
9/27/2017 US: Extended shelf life for Actinovate biological fungicides
9/13/2017 Plant-Prod introduces Duo-Tote
9/11/2017 US: Sun Gro, Proven Winners form sales & distribution partnership
8/28/2017 US: "Benefits from production to end consumer"
8/21/2017 Turkish investor starts organic fertiliser production in Zambia
8/11/2017 10 must-know growing media facts
8/8/2017 The challenges of fertilizing poinsettias
7/19/2017 NL: "Ekote makes additional fertilizing during the growth process unnecessary"
7/14/2017 US: RainSoil debuts natural silicon-based liquid soil amendment
7/12/2017 Fertilizing mums with water soluble fertilizer
7/7/2017 Plant-Prod to showcase new Duo-Tote at Cultivate’17
6/7/2017 Earth Alive's Soil Activator registered in Ukraine
6/7/2017 Mycorrhizae and plants make great allies
6/6/2017 US: Nutrient, pH, alkalinity, and ionic property levels in basins

 

Leave a comment: (max. 500 characters)

  1. All comments which are not related to the article contents will be removed.
  2. All comments with non-related commercial content, will be removed.
  3. All comments with offensive language, will be removed.




  Display email address

  new code