We've been growing cover crops since we started market gardening back in 2010. Anyone with an interest in organic agriculture knows that cover cropping is a way to cover soil that is not in use for cropping (instead of leaving fallow/bare soil), raise soil organic matter and tilth, sequester carbon, prevent erosion, grow mulch, suppress out of control weeds, feed soil biota and so many other things.
We've trialed a wide range of crops over time: mustard, oats, spelt, peas, blue lupins, white lupins, barley, buckwheat, daikon and a few others. Individually, these crops all have their own unique qualities. But when you mix them together and you really get some magic...
This year we got a hold of a particularly high carbon sequestering cover crop mix to help amend the heavy clay loam we are working with: Peas, hairy vetch, sunflower, popcorn, spelt, spinach and buckwheat. This mix has come from Kiwiseed in Blenheim, who have great technical knowledge on cover crops and offer a great range of seed.
Bulk biomass is provided by the large plants like popcorn, sunflower and hairy vetch, which sprawls and spreads over the entire area. This is all going to become organic matter in the soil as it decomposes. The peas and vetch are leguminous, and steal and secure atmospheric nitrogen back into the soil. Buckwheat is known to draw P (phosphorus) out of the soil and transform it into a plant accessible form once it has decomposed. The spread and depth of a wide variety of roots can loosen topsoil, create porosity and improve drainage. And, the combined colour of bright sunshine yellow sunflowers, delicate white buckwheat and a rolling ocean of purple vetch among the green backdrop is also very beautiful. These are the delightful aspects of organic farming.