Farm update week of February 20th; Caring for the soil, part 2

Winter came back a bit since our last update, and limited the amount of work we could do. But things are supposed to warm up again by the end of the week.

We planted out first batch of peas, under a row cover and a plastic covered tunnel. The peas were pre-sprouted in a can of warm water. Pre-sprouting helps seeds to germinate if the soil temperature is too cool or warm. Once the seeds start growing, they will continue to do so even if the soil temperature is not optimal. We used lots of bent rebar pins hammered into the soil to hold down the tunnel, in the hope that it won’t blow away. But since our farm is in a particularly windy spot, we will have to wait and see. I still don’t have pictures of this, but I’ll get them up soon, if it works!

In my last post on caring for the soil, I mentioned that there is an excess of potassium in the soil. Organic matter typically contains a large amount of potassium in it relative to other elements; potassium is used to build the structure of plants, and thus materials such as wood chips, straw, and leaves contain a lot of potassium, while the other more mobile elements have been leached out or moved by the plant into roots and seeds. So adding organic matter to our soil will increase the relative imbalance of potassium. This is a problem, because organic matter is very important to soil health. It helps the soil form a good crumb structure, hold water and nutrients from leaching away, and most importantly, feeds the microorganisms, which protect and feed the plants. The more life there is in the soil, the better, and organic matter is the fuel for this life.

To add organic matter without unbalancing the soil, we will be growing lots of cover crops, particularly rye, sorghum, oats, and clover. These plants will loosen the soil, protect it from the sun and wind, and add organic matter to the soil when they decompose, all without adding any more potassium. This is also more sustainable then importing organic matter from other soils to their detriment. Legume cover crops, such as clover, vetch, and field peas, also fix nitrogen from the air with the help of symbiotic bacteria. Eventually, we hope to grow all our own nitrogen in this manner and avoid purchasing nitrogen fertilizer.

Avoiding the importation of organic matter will also help us avoid any potential contaminants. Recently, new herbicides have been developed that do not break down in the composting process; they can contaminate straw, manure, hay, and grass clippings, and when applied to a farm or garden, can inhibit the growth of broadleaf plants for as many as seven years.

We recently borrowed a broadfork to assess its performance on our farm. A broadfork is a larger version of the standard garden digging fork, with specially shaped long tines, a wide crossbar, and two handles. For pictures and video of a broadfork in action, here is a link to the version made by¬†Valley Oak. I’m very happy with it; using it allowed us to loosen our hard soil a foot down, without the smearing and destruction of soil life and structure associated with tilling or plowing. Using it is also more enjoyable then using a tiller. Over time, the roots of the cover crops mentioned above will fill the soil voids produced by the broadfork, making the improvement permanent and creating a deep, rich topsoil.