Oats and Peas: Cover Crops

This summer we seeded ten acres of our farm with 2,000 lbs of oats and peas. This year and many times in the past I've been asked variations of, "why not harvest the grains?" One answer is that harvesting grains is difficult and complicated. When the grain is ripe, the plant is cut down (reaping). Then the grain has to be separated from the stalk (threshing), and the remaining chaff has to be cleaned off the seeds (winnowing). Big grain harvesting machines are called "combines" because they combine all these previously separate tasks (and then there's another machine to separate out the little grain-size rocks so we don't crack our teeth). Because most of the grain in the world comes from huge farms with huge machinery, the price of grain is pretty low, so it's probably the least valuable thing you can grow on a farm in terms of money. The difference between how a mega-farm grows and harvests lettuce, for instance, and how we grow and harvest it, is not that big. But the difference in how a mega-farm and a small farm grows a mechanized commodity like grain is a lot bigger.

Aside from all that though, the purpose of a cover crop is not to harvest it, so that all the energy embedded in the plant feeds the soil. Anything that's harvested takes something out of the soil, which needs to be replenished in some way. Fertilizer can do that a bit, there's compost which is also great, but growing plants and not harvesting them (cover cropping) is an essential component to long-term soil health. In the case of grain, you can harvest just the seed and leave the rest of the plant, which means that you're taking some and leaving some, but still it's not the same as leaving it all. From the outside, it can often look like "waste" for there to be a food crop in a farm field which is never eaten by a human, whether it's grains or carrots or cabbage or anything else. And we do harvest most of what we grow and either sell it or donate it (or sometimes organized gleaners come and harvest and donate extra crops). But the soil fertility that is the basis of our food has to come from somewhere, and anything left in the field will go back to the earth and feed the future.