by Jim Lane (Biofuels Digest) … One of the latest entries is a study out of the UK’s University of Southampton, with assist from researchers in Scotland and Italy, that delves into the pros and cons of the soil amendment known as biochar.
It’s a hot topic in the environmental world, where it’s been hailed because, as the Southampton researchers observed, “this carbon rich substance could potentially lock-up carbon and reduced greenhouse gas emissions. The global potential of biochar is considered to be large, with up to 12 percent of emissions reduced by biochar soil application.”
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The researchers found that an application of 50 tons of biochar per hectare boosts the plant growth rate of thale cress and lettuce by 100%.
But they warn that “[We had] negative findings for a suite of genes that are known to determine the ability of a plant to withstand attack from pests and pathogens. These defence genes were consistently reduced following biochar application to the soil, for example jasmonic and salcyclic acid and ethylene, suggesting that crops grown on biochar may be more susceptible to attack by pests and pathogens.”
Remembering those saccharine-loaded rats
Which all sounds highly interesting and relevant until you begin to count the number of farmers who, in the real world, would apply 50 tons of a soil amendment to a hectare of land.
Even in the land of high-yield crops like strawberries, the fertilizer load generally tops out 200-500 kilos per hectare. So it begins to remind one of those saccharine studies that produced cancer in rats if you loaded them up on a dosage equivalent to hundreds of cans of diet soft drinks per day, for life.
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Even if the biochar fraction is, say, 20% by weight, that’s something like 25,000+ tons of biochar in the planning mix right now, from those three plants. Now, the fraction could be smaller, we’re not exactly sure. But we look at that 827 ton annual volume in small-market sales, and it’s pretty clear that Cool Planet is going to need to find an industrial market.
Biochar’s target crops?
Where will Cool Planet look first? Think strawberries, tomatoes, peppers and celery. These are examples of relatively high-value crops grown in wetter or warmer climates that often struggle with poor soils and nutrient leaching.
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We know many things it can do. It’s better than compost, for one. It helps soil hold onto nutrients, it aids water retention and water quality, makes soils less acidic, reduce nitrous oxide and methane emissions from soil, reduce fertilizer and water needs and improve yields.
But we don’t really understand the mechanisms well — making it hard to improve.
READ MORE and MORE (Xconomy.com) and MORE (Biofuels Digest) Abstract