Several weeks ago, I received updated forage measurements from the University of California's Sierra Foothill Research and Extension Center (SFREC) in Browns Valley - about 40 miles north of our home place here in Auburn. For those of you who aren't rangeland geeks like I am, forage production on annual rangeland is measured in pounds of forage (grass and broadleaf plants) per acre. SFREC has clipped and measured forage for the last 40 years, so these monthly numbers give us a pretty good idea on where we stand compared to a "normal" year. And if you've read my blog posts over the last six months, you'll probably be surprised to learn that we were well ahead of "normal" on April 1 - I know I was surprised! On April 1, SFREC measured 2,570 pounds of forage per acre - a whopping 157% of average for the date. How is that possible? After all, we've only received about 70% of our normal precipitation through today! But these numbers, obviously, don't tell the entire story.
As you'll recall, February 2020 was the driest on record here in the Sierra foothills - we measured just 0.03 inches for the month here at home. February was also warmer than normal; the blue oaks were entirely leafed out by the fourth week of the month - at least three weeks earlier than I can ever remember. But in January, we had decent moisture, and March was close to normal. Based on my current observations of the condition of the annual plants on our rangelands, they've nearly completed their growing season (and remember, an annual plant must complete its entire life cycle - germinate, grow, reproduce, and die - all in the space of a year). Many of our annual grasses have already headed out - forage that usually keeps growing through May looks like it may be done for the year. In other words, we might be ahead of "normal" as of April 1, but our forage might be done growing. This might be all we get this year. It's enough for spring; will it be enough to hold us through fall - especially of fall is dry like 2019?
We've now moved back to our irrigated pastures closer to Auburn. Last week, the Nevada Irrigation District (NID) began delivering water to the ranch - and we started irrigating. Even with more than 3 inches of rain in early April, we've discovered that our pasture soils are dry. We irrigate for 24 hours in one location before moving to the next "set" - and we don't come back to that set for 12-14 days (what we call our "rotation"). Based on soil conditions, we should have started water on April 1 - too bad NID doesn't deliver summer water until April 15! This lack of soil moisture was evident this spring on our annual rangeland, too - the seasonal creeks really never ran at all. And since the oaks came out of winter dormancy early, they started pulling water out of the soil early, too - in late February, the vegetation under the oaks was beginning to wither.
Since the Big Dry of 2012-2015, every dry period during our normal rainy season makes me nervous. We feel like we've balanced our sheep numbers with our forage resources, but we're always looking ahead at least six months to be sure that demand (the number of sheep mouths we have to feed) is balanced with supply (the amount of grass available). A study highlighted in the San Francisco Chronicle late last week suggests that we may be on the cusp of a mega-drought - a multi-decade (or event centuries-long) dry spell. I'm not sure I know how to manage for that kind of drought!
In the meantime, I'm happy to have irrigation water this spring and summer. I'm happy to have enough grass to get us through the summer - and hopefully next fall. And I'm happy that, at least for now, we have more grass than "normal."
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