Soil erosion threatens our ability to feed ourselves in the future. Current concerns regarding soil erosion include economic vitality, environmental quality and human health.
How can losing a little soil to erosion be such a concern? Soil formation is a very slow process. It takes nature between 300 to 1,000 years to replace soil lost over a 25-year period at a loss rate of 1 mm per year (25 mm is approximately 1 inch)
Erosion reduces the productivity in several ways: Plants are not able to use nutrients as efficiently, seedlings are damaged, rooting depth is decreased, soil’s water-holding capacity is diminished, permeability is decreased, runoff increases and the infiltration rate declines. The loss of healthy soil leads to poor plant growth and lower crop yields.
In the United States we lose an estimated 6.9 billion tons of fertile topsoil to erosion each year. Losses of this size are far from sustainable. In an effort to continue food production, costly fertilizers and amendments are used to compensate for the lost soil. The loss of nutrients alone is estimated to cost U.S. farmers $20 billion a year.
As runoff carries sediment, nutrients, and agricultural chemicals off-site, the economic and environmental costs skyrocket.
The University of California has resources to help reduce the loss of soil through erosion. The free, five-page publication Understanding Soil Erosion of Irrigated Agriculture provides information to help maintain the productivity of land and reduce the enormous costs associated with erosion.
- Impacts of soil erosion
- Types of water erosion
- Indicators of soil erosion
- Soil survey interpretations
- Land capability classification system
- Soil erosion factors
- New soil survey resources
Additional resources, can be found at the UC ANR free publication website.
Yellow starthistle is thought to have been introduced into California from Chile during the Gold Rush. The weed readily took hold in California valleys and foothills, thriving in areas where the soil has been disturbed by animals grazing, road construction and wildland firebreaks. Today, yellow starthistle is a very common sight in vacant lots and fields, along roadsides and trails, in pastures and ranch lands, and in parks, open-space preserves and natural areas.
Capable of growing six feet tall and bearing flowers surrounded by inch-long spines, yellow starthistle reduces land value, prevents access to recreational areas, consumes groundwater and poisons horses. (Yellow starthistle isn't all bad. Beekeepers have found that it can provide an important late-season food source for bees.)
That's where goats can come in. Goats will eat yellow starthistle at all phases of growth, including the mature, spiny stage, when it is not palatable to other browsers and grazers.
"When goats eat yellow starthistle, they open up the canopy and allow sunlight to hit the ground," said Roger Ingram, UC Cooperative Extension natural resources advisor. "That allows other, more beneficial seeds to come up and grow. If you can get other plants growing in there, the competition will choke out yellow starthistle."
Landowners can raise goats themselves and direct them to areas of starthistle infestation with portable fencing, or they can lease the animals exclusively for vegetation control. More information on yellow starthistle management is available from the UC Integrated Pest Management Program.
View the video below for more information on goats' browsing preferences.
California must continually increase its use of renewable fuels to meet mandated reductions in greenhouse gas emissions (GHG). The state's historic Global Warming Solutions Act of 2006 (AB32) requires that alternative fuels displace 6 percent of gasoline and diesel use now, and 9 percent by 2012. The number goes up to 11 percent in 2017 and 26 percent in 2022.
California has been meeting these goals by importing millions of gallons of ethanol: 80 percent of the supply is corn ethanol from the Midwest, 12 percent is sugarcane ethanol from Brazil, and the rest is ethanol from corn grown here. By 2012, demand for ethanol fuel will rise to 1.62 billion gallons per year. If California does not increase its production of corn for ethanol, it will need to import 95 percent of that amount.
In the search for a better alternative, scientists have been investigating conversion of cellulose to ethanol. Technical challenges remain, but cellulose offers a potentially abundant feedstock for biofuels.
One of the plants seen as a possible dedicated biofuel crop in the United States is switchgrass. It is about 40 percent cellulose and grows widely in the Midwest and the South. However, it is not native to California and has not been produced here.
Recent studies by UC Davis scientists are the first ever to report tests of different switchgrass ecotypes in California, - and are published in the current California Agriculture journal.
Scientists evaluated the productivity of the two main ecotypes of switchgrass, lowland and upland, under irrigated conditions across four diverse California ecozones — from Tulelake in the cool north to warm Imperial Valley in the south.
”It is important to know how much biomass can be produced in the state before deciding to pursue cellulosic ethanol," says UC Davis plant scientist Gabriel Pedroso. "California has very diverse climatic regions, which affect the adaptability and productivity of switchgrass.”
Because it is a deep-rooted perennial grass, switchgrass promotes soil conservation. It stores carbon in its root system, and makes efficient use of water by virtue of its C4 photorespiration.
Switchgrass requires an establishment year.
"In the second year of production, the lowland varieties grown in the warm San Joaquín and Imperial valleys yielded up to 17 tons per acre of biomass, roughly double the biomass yields of California rice or maize," Pedroso said.
Because it can be used both as forage and as a biofuel crop, switchgrass may be well suited to California, a state with a large livestock industry and higher ethanol consumption than any other.
While the field trial results are promising, commercial, large-scale conversion processes for cellulose to sugars and fuels are just beginning to be demonstrated.
Cellulose is a complex matrix of smaller sugar molecules and fibrous material in plant cell walls. It is the principal structural component of all plant material, including residues and organic materials in municipal solid waste. If it were possible to efficiently break it down into simple sugars, if would become a productive source of ethanol, and would significantly reduce GHG.
The Coast Redwood Forests in a Changing California Science Symposium was held June 21-23, 2011, at UC Santa Cruz with just under 300 registrants in attendance. Participants ranged in background from graduate level students to university forestry and natural resource faculty, land managers, conservation groups, public agencies, and land trust members. The symposium was strategically held in Santa Cruz, near the Southern end of the redwood region. Designed to present the state of our knowledge about California’s coast redwood forest ecosystems and sustainable management practices, this symposium was built on earlier redwood science symposia held in Arcata, CA in June, 1996 and in Santa Rosa, CA in March, 2004. The symposium was jointly organized by the forestry programs at UC Berkeley, Cal Poly San Luis Obispo, and Humboldt State University, and partially supported by a grant designed to encourage research and outreach collaboration between the University of California and the California State University systems.
Attendees participated in a day long field trip and two days filled with opening sessions, concurrent presentations on research and management case studies, and a poster session. An ongoing theme of the symposium was the need for action and collaboration from all directions, including public and private land owners and managers, as well as academics and policy makers.
During the opening panel, local historian Sandy Lydon gave a synopsis of the settlement of the area and how the redwoods will always have a special history in the region. He recounted stories from his boyhood about roaming through the forests. He reminded the audience to take time from their schedules to spend time in the forests, and to urge their children to play outside to develop an appreciation for the outdoors and cultivate their imaginations.
Ruskin Hartley, Executive Director and Secretary of Save the Redwoods League, questioned what it means to save the redwoods today and argued that buying and placing land in public ownership is not enough. He believes the next 100 years will focus on restoring forests collaboratively between public and private entities. Hartley called on the audience to set “audacious goals and take collaborative actions.” He maintained that nature does not develop boundaries and that in moving forward, we should focus on a shared set of goals so that public and private land can progress simultaneously. In a time of climate change, the lines we draw on maps become increasingly irrelevant, instead we need a new paradigm to “think about building resilience and adaptability to climate change into the system to benefit both public and private owners.”
Ron Jarvis, Home Depot’s Vice President of Sustainability talked candidly about the role of environmental sustainability practices and policies as part of the home improvement retailer’s business model. He noted that when he began in the sustainability department he undertook a two year long project to understand where every sliver of wood from over 9,000 products originated to ensure sustainable wood practices. Recently, Home Depot sent a memo to their current vendors asking them to supply Home Depot with the names of their “green products.” The green product inventory exceeded over 10,000 products, yet when Jarvis’s team investigated further they deemed only about 2,000 to be worthy of the green standard. Jarvis showed that products today, because of packaging or brand names, may seem green, but the consumer must really investigate what they are buying. Jarvis hopes that in his position he can take some of that burden off of the consumer so that the majority of products that reach Home Depot shelves have already passed the test.
During the concluding ceremony on the future of research in the redwood region, the panel, as well as audience members, recognized the need for more communication among those working with redwoods to spread research findings and best practices. Inspired by the concurrent presentations and research presented at the poster session, participants were looking for a way to stay in touch and collaborate - as Hartley noted in the opening session is crucial for the next steps of redwood growth and preservation. 100% of participants who completed the follow up survey are excited to network and collaborate at similar events, meaning there are opportunities to further enhance the redwood and green movements.
Proceedings of the symposium are anticipated to be available in early Fall 2011 to document the various studies in the literature.
For a full summary of the 2011 Redwood Symposium, please visit: The Forest Research and Outreach Blog.
For ways you can get involved or if you have ideas for collaboration: Like us on Facebook and join the discussion!
The beauty of rolling hills studded with majestic oaks, other trees and shrubbery isn't the only reason to regenerate vegetation. The trees and shrubs create a much more hospitable habitat for a wide assortment of wildlife. Oak woodland vegetation also protects the quality of California water. The majority of the state’s water flows through oak woodlands in streams and rivers that support fisheries, farms and cities. Plants and trees anchor the soil, preventing erosion and stream sedimentation.
One of the difficulties ranchers face in regenerating trees is supplying water for seedling establishment. Ranches often stretch for thousands of acres. Hauling water to remote sites or installing irrigation can be prohibitively expensive.
Third-generation San Miguel rancher George Work heard about a new tree establishment invention from Holland – a Groasis Waterboxx. Over the years, Work has collaborated with UC Cooperative Extension on oak planting projects and consulted with UCCE experts about squirrel diseases, ranch animal vaccinations and pasture management. He turned to UCCE natural resources advisor Royce Larsen for his thoughts on the Waterboxx.
“Because of Royce here, our Cooperative Extension agent, he provided a little added incentive when I wanted to try this thing,” Work said. “Royce said, ‘I’ll help you.’ Well, that was enough to get the job done.”
Work, Larsen and UC Cooperative Extension natural resources specialist Bill Tietje installed 10 Waterboxxes, which cost about $30 each, in a remote area of the 12,000-acre Work Ranch in southern Monterey County. Other plant regeneration methods – including traditional drip irrigation and tree teepees – were also installed for comparison.
The Waterboxx is a round plastic hat box-shaped reservoir that fits around the seedling trunk. When the seedling is planted, the reservoir is filled with about four gallons of water. A rope on the bottom continuously wicks moisture to the plant roots.
The box is covered with an inward-slanting corrugated top that cools during the night and channels condensed dew and fog into the reservoir, keeping it full of water. The Waterboxx provides a protective barrier around the trunk and shades and cools the soil beneath. At the Work Ranch, the plants are also enclosed in bale-wire fence to keep out wildlife poking around for water or hungry for tender green growth.
“The trees are doing surprisingly well," Larsen said. "In just three months, the seedlings have grown more than two feet."
Larsen said he will continue monitoring the project to see if the self-watering system can establish trees. If successful, UC scientists may study the Waterboxx more thoroughly in a replicated research design in Monterey County, San Luis Obispo County and other parts of the state.
See the components of a Waterboxx in the video clip below.