We just wrapped up harvest of our pistachios — a bumper crop. Most years, we irrigate the orchard once afterwards and then wait for it to rain. We normally finish irrigation of all our permanent crops in October. Last year, however, when the rain didn’t come we continued to irrigate the orchards — every month, once a month, all through the winter. I hope we don’t have to do the same thing this year, but for now, we’ll keep irrigating until the rains arrive.
Our annual average precipitation in Winters is over 20 inches. That is 20 inches of water spread over our entire farm that soaks into the ground during the winter. Once the leaves fall off trees and vines, they don’t use any of that water. It percolates down into the ground where at least some of it stays available for the trees when they begin to bloom and leaf out the following spring. If a tree root cannot access freely available moisture when it becomes active, it will not support the growth of leaves and flowers or fruit. And if the soil around a root dries out completely, it will die.
When our trees and vines starting leafing out in spring of 2021, we had only received 6 inches of rain — not nearly enough to keep the soil moist around the tree roots. And once this happens, the trees begin to use an incredible amount of water as it moves from their roots into the leaves and then is evaporated into the dry, hot summer air. It is very difficult, bordering on impossible, to actually build up soil moisture once the trees start consuming water.
Most orchard growers in our area are unaccustomed to irrigating during the winter, and some have no water available to do so — the water districts stop delivering water after Halloween. But waiting too long to start watering an orchard — hoping for rain until February or March — means it is impossible to make up for the deficit if the rain doesn’t come. The result: very light crops, no crop at all, increased disease or even significant tree mortality. In our area right now, the tops of many trees show dead and dying branches, mirroring what is hidden underground — roots in dry soil dying. If you have trees in your yard or neighborhood that are never irrigated, you will likely be able to spot the same thing happening to them.
People have been asking me for months: “Are you watering your crops less because of the drought?”. That’s not the way to save water. Conserving water in agriculture is about increasing efficiency: using irrigation methods that deliver the water directly to the plants while reducing evaporation and other “waste”. Since the last drought, a huge percentage of our state’s farmland has been converted over to more efficient irrigation techniques. But growing crops here takes lots of water, and with summers getting hotter thanks to climate change, it always will.
Unfortunately, the media tends to focus on things like “dry farming” of certain crops and “drought resistance”. There are a tiny number of crops that can actually be grown in California in the summer with no irrigation at all, and even then, only in places that are cool and foggy. And reducing or eliminating the amount of water used almost always has the effect of reducing total crop yield. Dry-farmed crops usually sell for a higher price as a result.
The simple reality is that growing crops in California during a drought requires more water, not less. Trying to cut back on the amount of water used translates into less food produced. So if a farmer is going to irrigate a crop at all, it should be irrigated properly. Otherwise, a precious resource is being underutilized. As the drought continues, farmed acreage in California will drop accordingly and less food will be produced.
Here at Terra Firma, we will continue to make wise use of the water that is available to us and try to get as much food per gallon as possible.