If you drive or fly over the Central Valley during the spring, summer and fall, you will see vast expanses of lush green fields growing alfalfa for hay, a mainstay of the diet of cows and horses. You can make hay out of many different plants, but alfalfa is the most prized because it is a legume. It provides animals with more protein than grass hay.
When the subject of agricultural water use comes up, many people like to “hate on” alfalfa. Although almonds have recently claimed the prize of “most hated” crop in California, for years it was alfalfa hay that earned the most scorn for “wasting” water. After all, hay is (usually) a low-value crop, at least on a per-pound basis. And it does take lots of water.
Of course, alfalfa is not considered “low value” by the farmers who feed it to their livestock. Nor by the ones who grow it. Since it produces as much as 5 crops a year in California, it actually generates a respectable return to the farmer that grows it. And while it’s true that quite a bit of it gets exported, the majority of it gets used right here in our state.
But alfalfa’s real value is not economic. It is agronomic.
All good farmers grow legumes as part of their crop rotations as a way of resting and “rebooting” the soil. Legumes pull nitrogen from the atmosphere into the soil around their roots, providing their own fertilizer through acomplicated symbiotic relationship with bacteria.
A farmer may grow legumes as a “cover crop”, solely to build up the soil. We do this with both winter and summer legumes like vetch and cowpeas. We also grow leguminous cash crops, like the green beans in your boxes today or the snap peas we grow in the spring.
Alfalfa, on the other hand, is both a cash crop and a cover crop. Because it’s a perennial crop that produces for up to five years, it gives the soil a long rest from both tillage and harmful weather. Looked at another way, it is a paid vacation for the soil.
All legumes require lots of water. They are lush, vigorous plants. At Terra Firma, we keep our green bean fields soaking wet right up until harvest. Happier bean plants produce more beans of higher quality.
Legumes are also almost all “low value crops”. Beans and peas, whether dry or fresh, produce a small amount of food per acre compared to other crops. And even though they are “expensive” to consumers, the total income to the farmer is small.
The real value of legumes accrues after they are gone. The green bean field we are currently harvesting will host next year’s tomatoes. Once we finish harvesting the beans, we will plant another legume in the field: vetch cover crop. It will protect the soil from wind and rain in the winter while pulling in even more nitrogen from the atmosphere.
We don’t grow alfalfa at Terra Firma because it is harvested mechanically with specialized equipment. And we don’t have the large acreage that would be needed for us to take a chunk of land out of vegetable production for four or five years. But if we did, we certainly would.
As an organic farmer, I cheer anyone who is doing their best to protect and build their soil for the future. Don’t hate on hay.