Greenland’s Rock Flour Could be Soil, Climate Solution

April 21, 2023

Greenlandic Glacial Rock Flour Improves Crop Yield in Organic Agricultural Production:

The application of mechanically crushed silicate minerals to agricultural soils has been proposed as a method for both improving crop yields and sequestering inorganic carbon through enhanced mineral weathering. In Greenland, large quantities of finely grained glacial rock flour (GRF) are naturally produced by glacial erosion of bedrock and deposited in easily accessible lacustrine and marine deposits, without the need for energy-intensive grinding. To determine if this material can improve crop yields, we applied 10 and 50 t GRF ha−1 to a sandy, organic agricultural field in Denmark. Two field trials were carried out to test the first-year yield response to GRF in both maize and potatoes, residual effects on potato yields in the year after application, and second and third-year residual effects on spring wheat. Reference-K treatments were included for comparison to determine if the beneficial effects of GRF were primarily due to its K content (3.5% K2O). This alternative source of silicate minerals improved crop yields in the year of application. Though there was no improvement in yield with the reference-K treatments, for each additional ton of GRF applied, maize dry yield increased by 59 kg ha−1 and potato tuber yield by an additional 90 kg ha−1. No residual effects on crop yields were observed in the following years, but we suspect that benefits might persist over multiple seasons at sites with lower initial fertility. The increase in yields achieved with GRF could offset some of the costs of applying silicate minerals as a CO2 sequestration scheme.

If you’ve ever been to the front of a land terminating glacier in Greenland, you’ll know about the dust.

Microscopically fine, it gets into literally everything, and steady winds keep it whipping across vast effluvial plains, where it exists in kilometers wide deposits hundreds of meters deep.


2 Responses to “Greenland’s Rock Flour Could be Soil, Climate Solution”

  1. rhymeswithgoalie Says:

    Beautiful camera pan of rock flour outwash plain (aka sandur) ending in nice shot of subglacial stream “jacuzzi”.

  2. rhymeswithgoalie Says:

    Nerd* note:
    Research paper shows the median grain size of the Ilulialik glacial rock flour of 2.6 μm, or .0026mm, essentially putting it at the bottom of the scale. Note this is pretty much the same as the notorious PM2.5 fine particulate matter that can penetrate all the way into the lungs (alveoli).

    [NB: In geology the term “clay” can refer to either a class of minerals or a grain size, depending upon context.]

    *Dammit, I sat through all of those geology/petrology classes and I’m going to spew it back to the world from time to time.

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