- Author: Dan Macon
Fair warning - you might want to file this blog post under the category, "Aren't Ranchers Ever Happy?!" I'll admit - last year, I was worried about warm temperatures, lack of soil moisture, and dried-up stock ponds here in the Sierra Foothills. We'd had the driest January-March ever recorded. Seasonal creeks weren't running. A lack of stock water was limiting access to some pastures for ranchers in my four counties. But thanks to an early start to the grass season (a germinating rain in October) and warmer-than-usual temperatures, followed by rain (at last) in April 2022, we had plenty of grass from Yuba County south through Placer County. According to the Sierra Foothill Research and Extension Centern (SFREC) in Browns Valley (Yuba County), we had 3,806 pounds of forage per acre on May 1, 2022 - 20 percent more than the historical average for that date. Total precipitation from October 2021 through September 2022 was 21.2 inches - about 17 percent lower than the historical average.
The year before that (the 2020-21 water year) was even stranger. That year, SFREC measured just 10.57 inches of precipitation - the driest year since 2000 (drier, even than the worst of the drought years of 2013-2015). Even with the lack of moisture, however, the grass grew - total production was 108 percent of the historical average (3,382 pounds per acre). Once again, most seasonal creeks didn't run. Spring-fed stock water systems failed. But we had grass.
So where do we stand this year? The 2022-23 water year has been phenomenal. We have a near-record snow pack here in the northern Sierra Nevada. The southern Sierra Nevada has the most snow ever recorded! The creeks are running! Ponds are full! The May 2, 2023 Drought Map shows our region of the Sierra Foothills has escaped the drought!
And we're seeing less forage on May 1, 2023, than we saw in either of the last two drought years!
How can this be?! As of today, SFREC has measured just under 35 inches of rain since October 1 - 42 percent more than "normal." But the May 1 forage production figures are below average - just over 3,000 pounds per acre (about 4 percent under the historical average). What's going on here?
Annual rangelands are notoriously complex (in terms of biodiversity, phenology, and productivity). We've known for some time that forage production on our foothill rangelands has as much to do with the timing of precipitation as it does with the total amount. Forage production also depends on adequate soil and air temperature - warmer soils and warmer ambient air temperatures, given adequate moisture, result in greater forage production. Colder temperatures and cloudy days, on the other hand, tend to work against grass growth - as we've seen during this unusually chilly spring in the foothills.
We also know that photo period - the number of daylight hours - plays a role. I've usually thought of this in terms of winter dormancy - in early December, the days are short enough that the grass goes dormant here in the foothills, regardless of moisture or temperature. This year, however, is teaching me that photo period may be equally important in controlling when our rangeland plants flower and set seed. Even though we still have tremendous soil moisture in our rangeland pastures, I'm seeing many of our annual grasses and broadleaf plants "head out" and go to seed - they're just about done growing, despite what seem like favorable conditions. As any rancher will tell you, as soon as our annual forages go to seed, they drop in palatability and nutritional value.
I'll admit, I can't truly bring myself to call this a drought year. I can live with 96% of normal forage production - it's considerably better than the 2100 pounds per acre we had on May 1, 2015 (when I managed the cow herd at SFREC). But this year is an important reminder about how complex our grazing systems truly are. Carrying capacity fluctuates from one year to the next - and from one month to the next. Our job as ranchers is to build enough flexibility into our management systems to allow us to "weather" the valleys in forage production, and benefit from the peaks!
- Author: Dan Macon
Here in Auburn (on December 17, 2020), we received 0.64" of rain overnight. After a late start to the rainy season (and to germination on our annual rangelands), any rain is welcome at this point. But last night's rain continues an interesting (and potentially troubling) trend - our storm total was about 60 percent of what forecasters predicted earlier in the week. Similarly, last weekend's storms delivered less moisture than predicted. Our seasonal total (since October 1) is just over 4 inches; our average seasonal total here in Auburn over the last 20 years is over 11.5 inches - in other words, we've received just 36 percent of our "normal" precipitation so far.
On the positive side of all of these numbers, we have received enough rain to keep the grass that germinated last month going for a month or more. For our small sheep operation, we'd established a key date of December 31 for implementing more drastic drought measures (like buying more hay or selling sheep). With 1.89 inches of rain this month, and with the forage we've saved due to our conservative stocking rate and diligent grazing planning, we should make it through lambing without much added expense.
But the pattern remains concerning. I've noticed over the last several years that precipitation forecasting has become more accurate. While the exact timing of storms remains difficult to predict with down-to-the-minute accuracy, forecasters have become more adept at predicting storm totals several days out. That this year's storms seem to be falling short of predictions suggests that forecasting remains an inexact science.
Obviously, rainfall on our annual rangelands does more than grow forage. Many operations rely on run-off to recharge seasonal creeks and refill stock ponds. Without stock water, some producers won't be able to use the forage they saved from last spring (or they'll need to haul water). In the medium-term, the lack of snowfall in the high country portends a challenging summer for those of us who rely on irrigated pasture. Fortunately, our local water districts entered the winter with adequate carry-over in their reservoirs, but a lower-than-average snow pack is definitely concerning!
So while while our operation has made it through the first critical date of our drought plans, we're not out of the woods yet. After lambing is over in late March, our next major decision point will be weaning. We usually wean the lambs in mid/late June - sometimes as late as early July. In order to save forage on our annual rangeland for next fall, we may wean and sell our lambs early, allowing us to graze dry ewes on irrigated pasture into midsummer (which reduces our forage demand). I suspect our next decision date will be sometime in mid/late April.
I won't reiterate how difficult 2020 has been on a variety of fronts - drought just seems like one more crisis on top of a crisis-dominated year. I would encourage you to check out the Rangeland Drought Information Hub on the UC Rangelands website, however. You'll find a variety of resources for responding to drought conditions. From my perspective, the best time to start planning for drought is while it's raining. The second best time to start planning for drought is now! If you'd like help developing a drought plan or considering specific decisions, contact me at dmacon@ucanr.edu.