Monday, April 28, 2014

Foothill Forage Conditions - Observations on Drought, Sheep Grazing and Vegetation

Some of our filaree is waist-high - at least to
10-year-old Emma!

If you've been reading this blog during the last 6 months, you're probably tired of reading about the drought.  I hope you'll bear with me - as someone who has been living with the implications of this drought on a daily basis, I'm trying to document (at least anecdotally) what the lack of rainfall has meant for the rangelands we graze with our sheep.  If nothing else, I hope that I can look back at what I've written this spring and remember what these conditions were like - and I hope my kids can look back and have some idea of what we went through.

Since mid-February, we've been grazing our sheep on annual rangelands near Auburn that have not been grazed for at least two years.  When we turned sheep onto these pastures on February 14, we'd finally had some rain, but the green grass was still very short.  We contemplated feeding some hay so that the sheep would have enough protein to utilize the old dry grass.  In the first week the sheep were in this new location, we did feed several bales of hay.  Fortunately, the grass started to catch up with our demand shortly thereafter.  We did find ourselves moving the sheep much more frequently than in previous years.
The Flying Mule Farm grazers at rest!

Usually by February we've had enough precipitation that last year's dead annual grasses and forbs (broadleaf plants) have started to decompose - part of the carbon cycle.  This year, it was so dry that very little (if any) decomposition had taken place - we even had a 15-acre grass fire near where we were grazing in February.  Even now (late April), there seems to be more thatch than I'd expect to see in a normal rainfall year.  My friend and fellow rancher Joe Morris (who raises cattle near San Juan Bautista) calls this "trampling" carbon (as opposed to "grazing" carbon - or green forage).  My sheep will eat some of this dry forage, but it's not terribly nutritious.  Rather than force them to graze it, we try to utilize the other two impacts that grazing animals have on pasture plants (that is, trampling and manure deposition) to cycle this carbon through the system.  By getting this dead plant material in contact with the soil, we can help the soil microbes break down this carbon - improving soil health, reducing fire fuel loads, and (hopefully) encouraging a healthier stand of forage plants in future years.  Indeed, much of the thatch we're seeing this year is last year's medusahead barley and yellow starthistle - two highly invasive plants that are undesirable from a rangeland health and livestock production standpoint.  We hope that grazing and trampling will encourage more desirable plants to out-compete these invasives.
A healthy stand of ripgut brome - one of the more aptly-named
grasses in our annual rangelands.  Once it starts making seeds,
our sheep don't like it much.

Because of the dry year, we're also seeing our annual plants mature earlier than normal.  This means that they are going to seed earlier - and this process of reproduction makes them less palatable and less nutritious for our sheep.  They also seem to shorter in stature than in normal years, which means our rangelands are just not producing the same volume of forage they produce when we receive average precipitation.  And while I don't know this for sure, the composition of plant species on these rangelands seems somewhat altered.  We seem to have a great deal of filaree (an introduced annual broadleaf plant that thrives on disturbed soils), as well as ripgut brome (an annual grass as nasty as its name) and foxtail barley.  I'm not seeing as much soft chess and annual rye grass as I'm used to seeing in late April.  Some pastures seem to  have more clover (mostly annual rose clover and medics), while others have less.  I'm also noticing a fair amount of bare ground in some pastures - even in some where we haven't grazed.  Finally, we usually get fairly rapid recovery on our grazed rangelands in March and early April - in previous years, we've been able to re-graze pastures after 25-30 days of rest in the springtime.  This year, we're finding that we need to rest pastures for 45-50 days to allow for adequate re-growth.  Some plants are using the rest period to go to seed - also unusual based on past experience.
A sheep's-eye view of forage conditions on April 28, 2014.

So what does all of this mean to us in terms of managing our sheep?  Currently, we're grazing a paddock that has a fair amount of last year's yellow starthistle crop still standing.  We've placed our water trough and supplemental mineral in the midst of this thatch to encourage the animals to trample these old plants into the ground.  We're also hoping the sheep will eat the starthistle that's germinated this year - we hope that by stressing these new plants, we can reduce the amount of seed they produce this year.  Before I move them into a new paddock later in the week, I'll use my border collies to herd the sheep through the thickest stands of thatch.

We're now done lambing, but many of our ewes are at peak lactation - which means they need as much as 60 percent more forage as they require when they are not lactating.  The older lambs are starting to graze, too - we now have 300+ mouths to feed as opposed to the 150 we turned out on these pastures in mid February.  As the forage matures, we'll keep a close eye on quantity and quality - if quality starts to drop in May, we'll consider weaning the lambs earlier than normal.  Once we've weaned their lambs, the ewes can go onto much rougher, lower quality forage - it actually helps dry up their lactation more quickly (which is a good thing health-wise).  We'll also look at selling any older ewes that didn't have lambs this year - further reducing our forage demand.  We will keep a handful of replacement ewe lambs, and we'll likely raise a handful of lambs for our own freezer this year.  The rest of the lambs will be sold - which will allow us to save most of our limited summer irrigated pasture for the ewes.

I've seen recent long-range weather forecasts predicting El Nino conditions for northern California in the coming winter.  We'll see - some El Nino years have been wetter than normal, others have been drier.  For now, we'll continue to be conservative in our stocking rates and flexible in our grazing plans.  Our ability to move our sheep to available forage is probably our most important drought strategy.
Before turnout in our current paddock.
Lots of last year's starthistle.

A close-up before turnout.

After 22 hours of grazing

Close-up after 22 hours.

Another close-up of trampling impacts - I like to see
this carbon making contact with the soil!

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