The sustainable farming and land management industries are constantly coming up with innovations to find biological solutions to problems that have been solved through petroleum use since the 1940s. Brassica cover cropping is one example of this.
Brassicas typically have a large taproot and for ease of visualization, the most promising plant in this system seems to be the Radish. Sown in the late summer, the radishes drive their taproot into the soil as they take up nutrients. They are not harvested but left to last through a few freezes resulting in their death. As they decay, the nutrients are released back into soil and the taproot leaves a cavity in the previously compacted shallow layers of topsoil. Hence the tiling effect without mechanical soil turning that disrupts microbial activity and over-oxygenates the soil.
Erosion resistance and water absorption are boosted so well by this process that many riparian managers are studying the effect of planting them in drainage areas. Urban sprawl of impervious surfaces change the hydrology of the area by providing a flush of water during precipitation rather than an sponge-like absorption by local soils that gradually releases stored water into waterways. By aerating the remaining available soils with brassica cropping, that rush of creekbank-eroding rainwater can be somewhat alleviated.
I haven’t found much scientific data (at least not behind a paywall that double dips into taxpayers’ pockets). However there is a bit of literature from the Natural Resources Conservation Service (government source and PDF warning!) that makes me think this is an interesting development to follow!
I was introduced to this concept by my friend who is the farm manager at Frying Pan Farm Park in the bustling DC metro area. Being the last working farm in the county, they strive to strike a balance between typical farm operations and acting as a working farm museum for public education and enjoyment. Its great to see a farm with such a strong public presence exploring concepts of sustainable farming!