Posts Tagged: soil
“Soil is a life-sustaining natural resource that often goes unnoticed,” said Anthony O'Geen, UC Cooperative Extension soil specialist in the Department of Land, Air and Water Resources at UC Davis. “But soil is fundamental for production of food, animal feed, fuel and natural fiber as well as performing many critical ecosystem functions, like filtering water, cycling nutrients and maintaining biodiversity.”
Moreover, soil is an extremely limited natural resource. Three-quarters of the earth is covered by water. Half of what's left is desert, swamps, frozen solid or mountainous – areas unsuitable for agricultural production. Land that's rocky or floods annually further reduces space for growing crops, leaving just a tiny fraction of the earth's surface as arable land.
These limited areas of productive soils on earth are threatened by expanding urban development, unsustainable soil management practices, pollution and overgrazing. Other natural resources – like air and water – garner more attention as they enjoy much greater visibility, while soil is kept in the dark and treated like dirt. UC Agriculture and Natural Resources is taking part in the year-long celebration of soil to help give soil the recognition it deserves and promote policies that will protect the earth's soil for future generations.
O'Geen is the chair of the Soils and Biochemistry Graduate Group at UC Davis. As a UCCE specialist, he said, he is trying to get students more involved in outreach and sees the International Year of Soils as an ideal rallying point for 2015. The graduate students kicked off the Year of Soils in December by sponsoring a “PED Talk” competition. (Ped is a scientific term for an aggregate of soil. It was selected in a nod to the world-famous TED Talks.)
Graduate student Katy Dynarski won first prize and $250 for her five- minute talk titled “I ♥ soil.”
“We're continuously taught throughout our lives that soil is something bad,” said Dynarski in her presentation. “You ‘soil' your reputation. You keep ‘dirty' secrets.… In this way, we create a fundamental disconnect between ourselves and soil and we are able to banish it to the realm of things that just don't matter.”
Another student, Jessica Chiartas, invoked the world's celestial connections in her presentation.
Messages about the significance of soil conservation will be shared with California state legislators at Ag Day at the Capitol in Sacramento on March 18. An annual celebration of the state's diverse agricultural industry, the event draws farmers, 4-H members, commodity groups and agencies who work with the state's agriculture industry – including the UC Division of Agriculture and Natural Resources – to the state capitol's front steps. Elected officials, their staff, California state workers and the public visit and learn about California agriculture.
Other UC activities marking the International Year of the Soils are aimed at extending to farmers ways they can preserve and protect the soil on their California farms. The Conservation Agriculture Systems Innovation Center (CASI) – a collaborative project coordinated by UC that involves farmers, researchers and representatives of public and private agencies and environmental groups – is a leader in promoting soil health. The group conducts research and extension activities aimed at helping landowners maintain and improve their farms' productivity with soil management systems like cover crops, reduced tillage and no-till, and crop rotations. These systems are intended to cut sediment loss from farms and ranches, reduce dust emissions, conserve water and sequester carbon.
CASI has outlined three soil-health initiatives to accomplish during the International Year of Soils. The group will hold a series of demonstration evaluations and information-sharing field events throughout the year. The soil health outcomes from the long-term conservation agriculture and cover cropping research project at the UC West Side Research and Extension Center will be presented to 100 different audiences. A 10-segment soil health video series will be developed along with the USDA's Natural Resources Conservation Service.
The videos will present the underlying theory and principles of soil health with particular emphasis on conditions in the Central Valley. It will include vignettes about local farmers who have successfully improved soil function on their land while lowering production costs.
“Too often it seems that a big part of the information we get on soil health comes from far away in regions not at all like what we have in California,” said Dennis Chessman, NCRS state agronomist headquartered in Davis. “What we really need are examples of what works right here in the Central Valley and that's what we're trying to now develop.”
Mitchell, who has devoted his 20-year career to researching and promoting practices to improve soil health, said the International Year of Soils is adding momentum to ongoing complimentary soil health efforts in the U.S. and worldwide that have been building slowly for years.
“We need healthy soils now and in the future to provide a secure food supply to the world population,” Mitchell said. “The International Year of the Soil will help us reach the public with this fundamental work.”
An initiative to maintain and enhance sustainable natural ecosystems is part of UC Agriculture and Natural Resources Strategic Vision 2025./a>
Russell Ranch Sustainable Agriculture Facility.
The 72-acre “Century Experiment” at Russell Ranch is exploring the long-term impacts of crop rotation, farming systems, and inputs of water, nitrogen, carbon, and other elements on agricultural sustainability. Researchers document trends affecting crop yields, soil quality, profitability, environmental impacts, and efficiency in use of limited resources.
“We look at both organic and conventional systems,” says Russell Ranch director Kate Scow, a professor in the Department of Land, Air and Water Resources at UC Davis. “We're continuing to learn how to better manage both systems in the long term, but it's also important to identify new farming systems that incorporate the best parts of both.”
The theme for the May 28 event is “Soil Matters: Underground at the Century Experiment.” Presentations will be made by faculty, farmers, graduate students, postdoctoral researchers, and visiting scholars. Topic areas include:
- Nitrate leaching, drought and irrigation management in agriculture
- Soil biology — microbial communities and impact on farming systems
- Biochar — carbon sequestration and nutrient impacts
- Soil nutrient budgets and management
The program gets underway at 8:00 a.m. with welcoming remarks, followed by a tour of research sites from the comfort of hay-bale wagons. Presentations move indoors to the barn at 10:30 a.m. A growers' panel discussion follows lunch. The program wraps up at 1:30 p.m.
Russell Ranch, part of the Agricultural Sustainability Institute in the College of Agricultural and Environmental Sciences, is a unique 1,500-acre facility with more than 300-acres dedicated to the study of dry-land agriculture in a Mediterranean climate. The crops grown there — tomatoes, corn and wheat — are the same crops grown in the region. Researchers have monitored changes in crop and soil properties, greenhouse gas emissions, weed ecology, and economic indicators there since 1993.
Among research highlights, scientists have shown that cover-cropped systems can be managed to store water in the soil, tomatoes grown with subsurface drip irrigation use less water and less nitrous oxide emissions, and the concentration of antioxidant compounds are higher in organic than conventional tomatoes.
“We may need to make some hard choices about water and nutrient inputs that could change the face of what we currently know as California agriculture,” Scow says. “So we need resilient systems that can endure and be productive in a changing and unpredictable climate.”
For additional information about the field day, contact Emma Torbert at firstname.lastname@example.org or (530) 752-5208.
Anyone can learn about the United States’ diversity of soils using SoilWeb, a nationwide database of soil variability first developed in 2004. SoilWeb reached a new milestone this year when it was integrated with Google Maps and designed to scale across any Web-enabled device – desktop computer, tablet or smart phone.
SoilWeb has dozens of uses. The information can inform insurers about flooding frequency and builders about locations suitable for roads, basements or septic tanks. The agricultural real estate industry, farmland owners and farmers interested in renting or purchasing land commonly need information about soil productivity and land capability. Knowledge of soil is also important to home gardeners and landscapers.
“SoilWeb’s a great way to understand the landscape you live in,” said Anthony O'Geen, UC Cooperative Extension specialist in the Department of Land, Air and Water Resources at UC Davis. O’Geen developed SoilWeb with Dylan Beaudette, now a Natural Resources Conservation Service soil scientist, when Beaudette was a Ph.D. student at Davis.
The SoilWeb allows users to find information about the soil at a location by standing at the site with a GPS-enabled smart phone or tablet or by entering an address, landmark or latitude and longitude coordinates for anywhere in the United States. The location’s satellite image opens overlaid with yellow polygons marking soil-type boundaries. For each of the polygons SoilWeb provides information about soil profiles, soil taxonomy, land classification, hydraulic and erosion ratings and soil suitability ratings.
For example, the soil under Disneyland in Anaheim is 80 percent Metz loamy sand, characterized as very deep, somewhat excessively drained soil that formed in alluvial material from mixed, but dominantly sedimentary rocks. This is likely of great interest to the Imagineers who are responsible for maintaining the theme park’s extensive landscaping.
All the soil information in SoilWeb was collected from the National Cooperative Soil Survey, organized by the Natural Resources Conservation Service. NRCS began collecting the information in the 1930s.
“The surveyors create a conceptual model of the distribution of soils and soil properties by digging holes, conducting field tests and characterizing representative soils in the laboratory,” O’Geen said. “Not all soil survey areas are the same. Areas such as agricultural regions have more detailed information compared to cities. Because they started so early, they never dreamt of the intended uses of the land and demands required of soil surveys. Today, our methods of collecting data have become much more rigorous and new surveys of urban landscapes are much improved.”
The soil survey reaches about five feet below the surface or to bedrock, O’Geen said. One shortcoming of the database is in some urban areas the soil is classified simply as “urban land.” Where the California State Capitol is situated in Sacramento, for example, the locale is considered 100 percent urban land. No other information is given.
“That’s unfortunate,” O’Geen said. “They are changing that. Surveyors are remapping critical areas, but it’s tough. You can’t dig holes easily in cities.”
In addition, on some rugged terrain in the West, surveys haven’t yet been completed, including parts of the Mojave Desert, Calaveras and Tuolumne counties.
“Soil survey is one of the most detailed and expansive spatial data sets in the world,” he said. “It’s a tremendous resource that has helped our nation conserve and carefully manage soil and water resources.”
Find SoilWeb at http://ucanr.edu/SoilWeb.
Approximately every ten years, the research team at the Russell Ranch Sustainable Agriculture Facility at UC Davis gets the chance to dig deep into their research material to help answer questions about the long-term sustainability of agricultural systems.
With a steel probe attached to the back of a tractor, the team digs three meters deep to take soil samples at 432 different points around the 72-acre field. The initiative takes the team nearly a month to complete, and the information in each soil core can answer major research questions about the long-term effects of different farming methods on soil health and help inform year-round research efforts at the ranch.
“The effort that has gone into collecting this unique set of samples will pay off in figuring out agricultural impacts on processes happening not only in plain sight, but also out of view, buried deep in the soil,” said Russell Ranch director Kate Scow.
The sampling effort is part of the Century Project, Russell Ranch’s 100-year-long experiment. The project divides 72 acres of land into individual one-acre plots, with each plot given different treatments throughout the year. Some plots are irrigated; other plots are farmed without added water. Some plots are treated with compost; others are treated with synthetic fertilizer. Each individual plot demonstrates how a combination of different practices can affect crop yield, soil health and the health of surrounding ecosystems.
The 10-year sampling is a comprehensive look at the system, meant to serve as a baseline in determining the soil health at Russell Ranch. And there are a lot of factors that influence soil health. The research team tests for changes in soil organic matter, organic nitrogen, phosphorous, and other elemental content. They also test for bulk density (the amount of compaction in the soil), moisture content, and the microbial community at different soil depths.
Too, the soil sampling efforts dig deeper in the soil than much research, bringing important new information to soil science.
“Historically, much of the research has focused on the top 15 to 30 centimeters of soil. Some previous ideas about the distribution of carbon in the soil and effects of tillage on soil health have been wrong because of this,” said Scow.
With the Century Project in its 19th year, the 2012 soil samples are the third out of 11 field-wide samples to be taken over the course of the project. Changes to soil can happen slowly, so a long-term focus allows researchers to update their research as new information and new technologies become available.
“The big questions scientists are asking have changed, so we’re hoping to implement a new set of research questions that will drive us for the next 20 years,” said Emma Torbert, post-graduate fellow at Russell Ranch. “The benefit of long-term research is that we are provided the time to respond to those changing questions.”
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.