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From the Alfalfa & Forage News blog (April 29, 2022)
What is vetch? There are several species that are commonly grown as crops, cover crops or weeds (see list at the bottom). Vetch is a winter-hardy legume that's favored by early fall rains, which we had lots of last October (5.5-in in 24-hr in Sacramento). Vetch is also a nitrogen-fixing plant that works well as a cover crop in farming systems. It's also a good forage for bees and other pollinators and has extra floral nectaries (glands on stems that produce nectar) that attract beneficial insects like parasitoid wasps that prey on pests.
Is it a good livestock feed? Yes and no. As an annual leguminous vigorous herbaceous plant, vetch has high protein and relatively low fiber and reasonably high yields. It's vigorous growth and N fixing qualities is why it is so valuable as a cover crop, but it can also be grazed or fed as hay. Its quality is lower than that of alfalfa or clovers (protein levels from 15-20% depending upon stage of growth). It is commonly grown in mixes with small grains or grasses as a mix in different parts of the US. Vetch hay is difficult to handle due to the vine-like characteristics, and caution should be used due to anti-nutritional compounds and livestock palatability.
Anti-nutritional compounds. However, vetch hay can cause serious (and potentially fatal) animal health problems, so is not recommended as a primary forage for horses and cows. Most of the anti-nutritional compounds are concentrated in the seeds, so immature harvests are recommended. Vetch seeds are poisonous; they contain cyanogenic glycosides and a diglucoside that can cause a neurologic disease. Although hairy vetch (V. villosa) and purple vetch (V. benghalensis) seeds are the most toxic (being very closely related), other vetches have toxic seeds too, including common vetch (V. sativa). In addition, a toxin in vetch foliage is associated with a dermatitis or skin sensitivity disease, though this is extremely rare and not well understood. Most cases of vetch-induced dermatitis involve black cattle, such as Angus or Holstein, and horses can also be affected, so there may be specific susceptibility explained by a genetic predisposition. Lack of good information makes is difficult to assess vetch hay suitability for small ruminants like sheep, though there is anecdotal information that suggests it might be okay for goats.
How about rangelands? Vetch growing on grazing rangelands is actually a good, high-protein feed for livestock. In open range, cattle typically won't graze vetch until it dries down and seeds have shattered. On a hot day you can hear dry pods snap, crackle, and pop, like a bowl of Rice Krispies. Vetch is not favored by livestock when green due to low palatability (bitterness).
How about pastureland? Fenced pastures loaded with vetch going to seed could spell trouble for horses and cows, especially if there is little else to eat. Toxicity risk can be alleviated by ensuring other forage options are available and by stocking animals at very low densities and giving them the option to selectively consume non-toxic plants and avoid toxic plants. Again, once the plant has dried down and seeds have shattered (detached and fallen), it should be okay as grazing feed.
How big a problem is vetch toxicity? The California Animal Health and Food Safety Laboratory at UC Davis has had a few cases of vetch toxicity to cattle and horses over the years, but not many. It's still unclear if this means few cattle are exposed to vetch or few cattle actually develop disease. It's still kind of a mystery as to why vetch is sometimes a problem and other times not. It might be a matter of the degree of its presence in animal diets – low percentage is okay, high percentage more problematic. "Dose makes the poison" as a toxicologist would say.
How about croplands? Oats and vetch used to be a popular mix for feed, but not anymore and hay growers try to keep it out of their forage crops. If cereal grains are in a crop rotation, vetch seed is about the same size as wheat and barley kernels, making it hard and expensive to separate during seed cleaning. Vetch is also hard-seeded, meaning seed can lie in the ground dormant for years and germinate when not wanted, though the viability for most seed is about 5 years, allowing opportunities for management. For control, one can mow prior to pod and seed set or use broadleaf or pre-emergent herbicides if needed.
Vetch identification. To differentiate different species of vetch one needs to look at the flowers. Common vetch (V. sativa) has flowers with a short stalk (peduncle), meaning the flowers are attached close to the stem from where it originates (picture). Hairy vetch (V. villosa), purple vetch (V. benghalensis), and American vetch (V. americana) all have flowers with long stalks. Hairy and purple vetch flowers are aligned on one side of the flower axis (picture) whereas American vetch flowers are more upright (picture). Purple vetch will generally have flowers about the same size as the leaflets (picture), while the flowers on hairy vetch are generally larger or longer than the leaflet (picture).
What types of vetch are found around California on agricultural and rangelands? According to Dr. Alison Colwell, Curator, UC Davis Herbarium, the following are the rankings of vetch (Vicia) species abundance by county. This information comes from the Consortium of California Herbaria (https://cch2.org). The data are from all years that collections were made, which is basically the past 100 years. The take-home point of this analysis is that there are several similar vetch species that are all spottily dominant around California.
Yolo County (all ag)
- V. villosa (hairy; lana/woollypod subsp. varia)
- V. sativa (common)
- V. benghalensis (purple)
Mariposa County (mostly ranch/public land, central)
- V. americana (American vetch; native plant)
- V. sativa
- V. benghalensis
Butte County (part ag, part ranch, north)
- V. villosa
- V. sativa
- V. americana
Tulare County (ag, arid, south)
- V. americana
- (3-way tie) V. benghalensis, V. sativa and V. villosa
Stanislaus County (ag, central)
- V. villosa
- V. sativa
- V. americana
Original source: Alfalfa & Forage Newsblog (April 29, 2022)
By Susanne von Rosenberg, UC Master Gardener of Napa County
It's May and everything is growing beautifully, including weeds. Even if your garden is exceptionally well-weeded, new invaders will creep in and demand attention. Our general reaction is to remove them as soon as we realize that we have them, and we think of a good, tidy garden as one that is free of weeds.
In general, until you are comfortable with weed identification, keeping your garden entirely free of things that you did not plant is a good approach. However, weeds can also provide some benefits, so learning about the different weeds can help you decide whether you just might let certain ones grow for a while. Over time, you may make friends with certain weeds and make them part of the cycle of your garden.
So what is a weed? Most commonly we consider something a weed if it is growing somewhere we don't want it to. Those California poppies you love in your flower beds just might be a weed if they start growing in your vegetable bed. I was surprised to learn that some people consider miner's lettuce, an edible California native that I carefully cultivated in my garden, a weed.
How can weeds actually be beneficial? Some weeds are edible, many can supplement your compost, and some help loosen the soil. They may provide erosion control and dust control. Some provide food or habitat for pollinators and other wild animals.
In addition, weeds can teach us about our soil. Certain weeds prefer specific soil conditions, so if you have those weeds, you can assume that your soil has those characteristics.
Common edible weeds include purslane, dandelion, lamb's quarters, nettles, fennel and chickweed. If you're not sure what you're looking at (you only know it's not something you planted), you can use the weed identification tutorials and information on the University of California Integrated Pest Management (UC IPM) site. If you're going to eat weeds (the ultimate revenge), use common sense. Never eat anything if you're not totally certain you've identified it correctly.
Many weeds make good additions to your compost or can serve as mulch. Annual weeds that have not developed flowers can be chopped up and left in place, although in winter and in moist areas of your garden, you have to make sure they don't re-root. You can also chop them and add them to your compost bin.
Those parts of perennial weeds that won't re-sprout can also be added to compost or used as mulch. With perennial weeds, though, it's important to know how they propagate so you don't inadvertently spread a problem. If a perennial weed has not flowered, you can also let it dry out completely (think completely crispy and brown) and then put it into your compost.
Some weeds improve soil by growing deep roots that break up the subsoil (the layer immediately below the topsoil). That allows the weaker roots of more delicate plants to access the water and nutrients there. Some common weeds with deep, strong roots include wild chicory, plantain, sow thistle and vetch, as well as lamb's quarter and purslane. Cut these weeds off at the soil surface before they start to flower. The roots will decay in place, adding organic matter to your soil. The tops can go into your compost. You'll get the most benefit if you keep these weeds fairly far apart; if they grow close together their roots won't penetrate as deeply.
Some weeds are great for attracting pollinators. However, you have to let the weeds flower. The mustard we see flowering in Napa Valley vineyards is one example. Fennel, wild radish and pigweed are other examples of weeds that are good pollinator plants. Pull them as soon as they have bloomed, and do not put the spent flowers in your compost.
Weeds can also act as living mulch. This feature can be particularly helpful in winter, if you are not growing vegetables or an intentional crop such as fava beans. Almost any annual weed can serve as living mulch. (You do not want to give perennial weeds the benefit of extra growing time.) Some annual weeds, such as chickweed and purslane, will form a mat as they grow and thus help suppress other weeds.
Finally, weeds give you clues about what is going on with your soil. Like other plants, weeds have specific soil preferences. Chicory, purslane and lamb's quarters are generally good news because they indicate rich soils. Thistles, wild turnip and bindweed, on the other hand, can indicate that you have compacted soil or a crusted soil surface. Poor drainage can be indicated by weeds such as sedges and Bermuda grass.
Research your weeds and learn what they tell you about your garden. Whether as indicators, food or soil improvers, weeds can be garden helpers, too.
Weed photo gallery list from UC IPM is here, a LIST OF ALL WEEDS. Find the common name to see a photo.
http://ipm.ucanr.edu/PMG/weeds_all.html
If you wish to ID the weed, use the UC IPM weed ID tool here:
http://ipm.ucanr.edu/PMG/weeds_intro.html
The UC Master Gardeners of Napa County are volunteers who provide University of California research-based information on home gardening. To find out more about home gardening or upcoming programs, visit the Master Gardener website (napamg.ucanr.edu). Our office is temporarily closed but we are answering questions remotely and by email. Send your gardening questions to mastergardeners@countyofnapa.org or leave a phone message at 707-253-4143 and a Master Gardener will respond shortly.
- Author: Kathy Keatley Garvey
If you've ever visited UC Berkeley's Hastings Natural History Reserve in the upper Carmel Valley, Monterey County, and admired the yellow-faced bumble bees and other native bees foraging on vetch and lupine in the meadows, that's a scene you'll never forget.
But did you know that a UC Berkeley-based entomology team provides workshops there on California's native bees?
This year the team of Professor Gordon Frankie of UC Berkeley, Distinguished Emeritus Professor Robbin Thorp of UC Davis, and UC Berkeley-affiliated trio of Sara Leon Guerrero, Jaime Pawelek, and Rollin Coville, will offer a workshop June 1-5 on "California's Native Bees: Ecology and Identification."
You'll learn about many of California's 1600 species of native bees. Extremely diverse, they "are critical for providing ecosystem services not only in wild habitats but also in agricultural and urban settings," the instructors said.
"This course will provide basic information about native bee biology and ecology with a specific focus on identification to the generic level. Course participants will spend time collecting in the field at the UC Hastings Reserve and at a nearby diverse garden in Carmel Valley. They will also spend time in the lab viewing and keying collected specimens. Evening lectures on a variety of related topics will add to the field experiences. This workshop is an extension of the previously offered weekend bee workshop, with more focus on bee identification."
"Bee collections from the Hastings Reserve date back several decades, so knowledge of important bee-flower relationships are well known for this site. Participants will learn about bees' flower preferences, how to collect bees using several different methods, information on how to create a bee-friendly garden, bee photography techniques, and bee identification using generic keys and microscopes."
Participants also will have the opportunity to purchase the book, California Bees and Blooms: A Guide for Gardeners and Naturalists, authored by Frankie, Thorp, Coville, and Barbara Ertter.
The workshop is in a rural setting, with a picturesque barn--built in 1863 by homesteader John Scott--dominating the landscape. Accommodations are in dormitory-style rooms with twin or bunk-style beds. There's also space outside for camping. Meals are provided from dinner on Wednesday through lunch on Sunday. Workshop fee: $695/$720.
For more information and registration, access the Jepson Herbarium, UC Berkeley website or email Jaime Pawelek at jaimep23@berkeley.edu.
In the meantime, access the UC Berkeley Urban Bee Lab, read about the history of Hastings here or download a PDF.