Forest Ink columnist Jim Hilton

FOREST INK: Long-term, positive results using an organic approach

Following a tip from a friend I viewed an interesting video concerning the addition of compost for range and forest soil enhancement.

John Wick described the use controlled grazing by livestock as a way to deal with weeds and improve his pastures at the same time.

He also described how a dusting of compost achieved similar or better results. I was a little skeptical about some of John’s claims but after reviewing their website, “Marin Carbon Project (MCP),” I understood the specifics of their work and realized how much research had also gone into the project.

Their findings were described as follows: “We found that a single (one-time) application of compost doubled forage production (increasing 40 to 70 per cent) and soil C sequestration (on average one ton/hectare) over three years on both coastal (wet) and Sierra Foothill (dry) Mediterranean grassland systems. Compost decomposition provides a slow-release fertilizer to the soils, leading to increases in carbon sequestration and plant production. Net ecosystem C storage increased by 25 to 70 per cent without including the direct addition of compost C, while compost had no effect on nitrous oxide N2O or CH4 emissions.”

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What was also impressive was how Mr. Wick, along with a consortium of independent agricultural institutions in Marin County in California, including university researchers, county and federal agencies along with nonprofits were able to move from research sized work to relatively large field trials.

The MCP work was similar to the results discussed during the soils course held at TRU this year which described the use of controlled grazing to improve pastures carrying capacity and weed control on a ranch in Manitoba.

The advantages of an organic approach relative to commercial fertilizer applications is the low impact on plant communities.

While fertilizer (with inorganic N) has been shown to drive plant invasions and often reduce diversity, compost (with organic N) does not have these negative impacts.

Results described in the MCP research shows that: “C storage would persist for 30 to 100 years, and that compost application resulted in a long-term increase in ‘C’ capture and associated nutrient cycling. Few differences were seen when applying small amounts for multiple years versus a single one-time application.”

While composting does involve more work it provides a more finished product compared to mulch or dried manure.

As described in the website: “Compost is the final product of a managed thermophilic process through which microorganisms break down organic materials into forms suitable for beneficial application to the soil. A well-managed composting process has plenty of oxygen, goes through a high-heat phase that accelerates the natural biodegradation of organic materials and produces a stable form of organic matter that is made up of carbon and nitrogen, contains other important nutrients, and is free of weed seeds and harmful pathogens. For environmental and agronomic reasons, it is important to note that the type of nitrogen found in compost (organic N) is not the same as the nitrogen in synthetic fertilizers.”

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With the abundance of residual wood fibre along with nitrogen sources from the farming and ranching community there should be some potential for a composting industry in the interior of the province.

There has been some research on the use of urban waste products for composting rather than treatment plants which eventually result in some effluent going into our river systems.

At a forestry level, compost would make sense for silvopastures, hybrid poplar plantations, land reclamation or small scale plantations.

Jim Hilton is a professional agrologist and forester who has lived and worked in the Cariboo Chilcotin for the past 40 years. Now retired, Hilton still volunteers his skills with local community forests organizations.


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