For many ranchers in the Sierra foothills and Sacramento Valley, irrigated pasture is a critical component of our annual forage calendar. In many ways, irrigated pasture has replaced the historic practice of "following the green" - of taking sheep and cattle to mountain pastures during the summer months. Green summertime forage in the foothills and valley requires irrigation in our Mediterranean climate - and so many of us spend at least part of every day from April through October spreading water across our pastures.
Here in the foothills, these pastures do more than feed livestock. Large blocks of green vegetation provide landscape-scale firebreaks that protect rural residential communities. These pastures support a great deal of wildlife, as well - I consistently see wild turkeys, blacktail deer, song birds, and hawks (just to name a few species) on our pastures near Auburn. At least to me, a well managed irrigated pasture is a cool, green jewel amidst the summer-time brown of our foothill landscapes.
Truly productive irrigated pastures don't simply appear once we start applying water, though. No matter how much I water the annual grasses that grow on our rangelands, these plants have to die each year - that's what makes them annuals! Establishing irrigated pasture is similar to planting an other permanent crop - it requires soil preparation, infrastructure development, fertilizer application, and seeding of perennial forage species (like orchard grass, fescue, and clover).
Once planted, irrigated pasture requires careful management, as well. Our irrigation system is designed to put enough water in 24 hours onto the pasture to meet plant needs for ten days (in other words, our irrigation "sets" are for 24 hours, and our "rotation" brings us back to the same location in the pasture every ten days). We also manage our grazing carefully - matching our rest periods with the growth rate of our forage. When the grass is growing rapidly in the springtime, we can graze the same paddock every 25 days; in the heat of the summer when grass growth slows, our rest periods are longer to allow the plants to re-grow before we graze them again. And to protect water quality, we try not to irrigated underneath the livestock.
Obviously, the decision to establish irrigated pasture - or to incorporate it into our production systems - must include economics! Establishing pasture - even one that will last for 20-plus years - requires significant investment. Once established, we have to pay for water, depreciate our equipment, pay for labor, PAY OURSELVES!
This spring, I collaborated with Don Stewart at the Ag Issues Center at UC Davis to update two cost studies specifically analyzing foothill irrigated pasture. Click on the links below to access them:
On a related note, I'm also collaborating with Dr. Leslie Roche, Cooperative Extension Specialist in Rangeland Management at UC Davis, along with a number of other farm advisors throughout Northern California, on a research project examining a variety of irrigated pasture management strategies. We're looking at grazing management, water management, forage production, soil health, and a variety of other parameters - stay tuned for more information on this project as well!
Now I need to go out and move water....
Smutgrass, in my experience, is a complicated, opportunistic weed, by which I mean there neither seems to be any single factor that contributes to its spread, nor any single management technique that leads to its eradication. Smutgrass seeds require bare ground, sunlight, and warm temperatures (68°F to 95°F) to germinate. Management practices (like pasture harrowing), or pests (like gophers) that lead to bare ground may provide a toehold for smutgrass establishment.
We have grazing exclosures established on several irrigated pastures on the eastern edge of the Sacramento Valley. The grazed portions of these pastures have significant smutgrass populations; the exclosures, where the forage grows all season without being removed, have little or none. To me, this suggests that getting the grazing right on our pastures may be part of the answer. If we can graze our pastures to 4-6" of stubble height, and then allow sufficient time for the desirable forage plants to regrow before we graze again, perhaps we can allow these "good" plants to outcompete smutgrass. On paper, this sounds easy; out in the pasture, it requires us to vary our graze periods and (more importantly) rest periods based on the growth rate of the pasture. Our rest period in June might be 25 days; in August it might be 40 days! Not every operation is set up to accommodate this variability.
We have noticed that dry ewes are more likely to graze smutgrass than lambs, particularly early in the season. Other producers have observed that goats will graze smutgrass. Davy et al. suggests that this may be related protein levels and digestibility. Clipping (or grazing) can maintain smutgrass in a more vegetative state, increasing palatability and nutritional value.
But even where we get the rest periods and graze periods right for the plants we want, we may still have smutgrass. Irrigation inefficiencies may favor smutgrass in some cases. Josh Davy and Betsy Karle found that smutgrass was significantly decreases on a pasture where irrigation was changed from a 14-day rotation to a 7-day rotation (with corresponding increases in more desirable grasses). I've noticed on the pastures that we irrigate for sheep that we seem to have more smutgrass in areas where shallower soils or lower water pressure results in less than optimal irrigation (in other words, we can't get enough water on these sites to maintain sufficient soil moisture in our 12-day irrigation rotation). And since our system is designed to run on 24-hour sets and 12-day rotations, we don't have a great deal of flexibility when in comes to addressing our smutgrass problem by adjusting our irrigation schedule.
Some producers in our region regularly clip their pastures to avoid eye problems and keep forage in a more vegetative condition. Research shows that repeated mowing can decrease the diameter of individual plants but increase the density of the stand. Mowing may also spread seed. On the other hand, mowing may maintain the nutritional quality of smutgrass further into the summer (which may improve its palatability for livestock).
Finally, glyphosate (RoundUp) may be a viable control option. A rotary wiper allows the operator to adjust the height of the wiper drum above the desirable pasture plants and "wipe" the herbicide directly on the smutgrass plants. This application should occur shortly after grazing (so that the desirable plants are lower than the smutgrass). According to Davy et al., "glyphosate should be applied after flowering when the plants are translocating sugars back to the roots or below-ground reproductive structures (generally late summer and early fall). Managing Smutgrass on Irrigated Pastures contains a helpful guide to using glyphosate with a rotary wiper. The Tahoe Cattlemen's Association has a wiper that is available for rent through Far West Rents and Ready Mix in Lincoln. If you'd like help learning to use the wiper, contact me at (530) 889-7385 or at email@example.com.
Weeds are often a symptom of a management problem, rather than the actual "disease" - if we don't address the underlying issue (in the case of smutgrass this may be grazing management, irrigation management, or other factors), the problem is likely to reoccur. And with a weed like smutgrass that seems to be so opportunistic, eradication may be especially difficult. Controlling it (rather than eradicating it) maybe the most cost-effective option.
We have a variety of livestock and pasture-focused workshops scheduled this spring! Check out the links for more information.
Penn Valley, CA
Co-sponsored by the Nevada Irrigation District and the Nevada County Resource Conservatory District, this FREE workshop will focus on soil management, irrigation systems, and pasture management. Participants must pre-register – contact Kaycee Strong at (530) 273-6185 ext. 244 or firstname.lastname@example.org.
Learn how to set up and manage a small-to-medium-sized shearing facility for small flocks. Participants will learn about sheep handling, shearing preparation, wool handling, and wool marketing. (Note: this is not a shearing school). Register at: http://ucanr.edu/woolhandling&shearingmanagement.
UC Sierra Foothill Research and Extension Center, Browns Valley, CA
This day-long workshop will include presentations on managing soils and forage, decision tools and strategies for managing livestock during drought, and climate data and visualization tools to support on-ranch planning. Register at: http://sfrec.ucanr.edu/?calitem=445275&g=62869
Shone Farm, Santa Rosa Junior College, Santa Rosa, CA
This 2-day, hands-on grazing school provides participants with practical, field-based experience in applying the principles of managed grazing on rangelands. Participants will learn to estimate carrying capacity and graze periods, as well as develop grazing plans and monitoring systems. For more information, go to: http://cesonoma.ucanr.edu/?calitem=446449
This one-day workshop will focus on the business practices and logistics planning essential to managing an effective and profitable targeted grazing business. UCCE Livestock and Natural Resources Advisor Dan Macon has managed medium-and large-scale targeted grazing projects in the Sierra Foothills and Sacramento Valley. Other speakers will include current contractors and grazing experts. Register at https://ucanr.edu/sites/Livestock/?calitem=450512&g=93567.
Stay up to date on other workshops and events at https://ucanr.edu/sites/Livestock//span>
Registration is now open for several livestock-focused workshops offered by the University of California Cooperative Extension!
2019 Cattlemen's Symposium - March 20, 2019 (9am - 1pm)
Co-sponsored by the Tahoe Cattlemen's Association, the 2019 Cattlemen's Symposium will feature presentations on Genetic Improvement in Beef Cattle by Dr. Alison VanEenennaam of UC Davis, Cattle Marketing and Added-Value Programs by Dr. Tina Saitone of UC Davis, Managing Cattle Health by Dr. Gaby Meier of the UC Davis School of Veterinary Medicine, and Managing Smutgrass on Irrigated Pasture by Josh Davy of UC Cooperative Extension.
The cost is just $15 per person and includes lunch! Register at http://ucanr.edu/2019cattlesymposium.
Livestock Protection Tools Field Day - March 29, 2019 (8:30am - 12pm)
Penn Valley, CA
Are you interested in learning about techniques for protecting your livestock from predators? Curious about nonlethal livestock protection tools but concerned about costs and effectiveness? Join UCCE for this hands-on field day. Our keynote speaker, Cat Urbigkit, operates a sheep and cattle ranch in western Wyoming. She'll share her experiences using livestock guardian dogs and other tools to protect livestock from wolves and other predators in extensive rangeland environments. The field day will also feature demonstrations of turbo-fladry, electric fencing systems, game cameras, low-cost GPS collars for livestock guardian dogs, and other tools. Wildlife Services specialists will cover preserving a livestock kill site, and George Edwards, executive director of the Montana Livestock Loss Board, will discuss compensation programs.
Please note: This field day is focused on on-the-ground solutions to predator losses in commercial ranching settings. The intended audience is commercial ranchers. We will be hosting a similar workshop for agency and nonprofit staff, as well as interested public, later in Spring 2019 – stay tuned for details.
No charge for this workshop! Please RSVP at http://ucanr.edu/livestockprotectiontoolsnevadaco/span>/span>
While it may be difficult to imagine with another atmospheric river storm bearing down on Northern California this evening, irrigation season is just around the corner. Most of the water districts in the foothills will begin delivering water around April 15 - and six months of moving water through irrigated pasture will begin for many of us! Here are a few tips to help make this coming irrigation season run smoothly!
First, we should schedule irrigation (or design our systems) to provide the right amount of water at the right time to meet plant needs. These obviously change as we go through the irrigation season - after this weekend's storm, we should have plenty of soil moisture for a week or more.
Plant and soil water demand, ideally, should determine the quantity of water applied and the frequency of irrigation. This will help improve forage quality, reduce runoff and increase water use efficiency. But how do we know what the plant and soil water demand is?
One of the easiest ways to determine this is simply to learn to assess soil moisture by feel. The Natural Resources Conservation Service has a great pamphlet entitled Estimating Soil Moisture by Feel and Appearance. If you'd rather have a hard copy of the pamphlet (it's even printed on waterproof paper), we have copies at the office!
Another way to determine soil and plant water demand is to use the California Irrigation Management Information System (CIMIS) to estimate evapo-transpiration (or ETo). ETo is the amount of water transpired by plants and lost through evaporation; CIMIS has weather stations throughout the state that provide regional estimates of ETo. The closest stations for our region include one near Auburn and one at the Sierra Foothill Research and Extension Center in Browns Valley. The CIMIS website provides data regarding daily (and even hourly) ETo, precipitation, air temperature, soil temperature, humidity, wind, and a variety of other parameters that can impact irrigation.
Finally, if you'd like to know exactly what's happening in your pastures, I can install a WaterMark moisture sensor. These sensors can help you track the effectiveness of your existing irrigation system and adjust the quantity of water applied and the frequency of application. Call the office if you'd like to schedule an appointment! You can reach me at email@example.com or (530) 889-7385.
In future weeks, look for additional blog posts about managing irrigated pasture! Also, mark your calendar for Saturday, May 19 - I'll be co-hosting an irrigated pasture workshop with the Nevada Irrigation District and the Nevada County Resource Conservation District in Penn Valley from 8 a.m. - 11:30 a.m. - stay tuned! In the mean time, enjoy the coming rain!