Cooperative Extension San Joaquin County
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Cooperative Extension San Joaquin County

Posts Tagged: greenhouse gas

New database captures the benefits of biochar

The origins of interest in biochar, a charcoal-based soil amendment, are almost mythic in nature. In the Amazon Basin, a rainforest region with typically infertile soils, segments of soil have been discovered to be almost black in color and rich in nutrients. The soil’s color is derived from its high organic matter content, believed to originate from historical charcoal applications added to the soil some 2,500 years ago, either intentionally or as a waste product from cooking. 

Recently, there has been a growing interest in whether the fertility of these “amazon dark earth soils” can be replicated in modern farming practices, and a new UC Davis database helps users and researchers better understand that replicability. 

The charcoal, called biochar when used as a soil amendment, can be derived from nearly any biomass, transforming waste products into this unique additive. Increased bio-fuel production and increased fruit and nut crops in California produce a growing supply of waste that has rich potential as a nutrient. Wood, chicken manure, the residue of corn plants after harvest, and nut shells are all common candidates for biochar, each cooked down in a low- or no-oxygen environment into brittle charcoal and added to soil.   ­­­­

The claims of biochar’s ability to improve soil are vast. Biochar proponents say its addition to soil can increase carbon storage, increase the nutrient and water retention of soils, and reduce the greenhouse gas emissions from soils. 

“The basic premise of biochar’s benefit is straightforward,” says Sanjai Parikh, assistant professor of soil chemistry in the Department of Land, Air and Water Resources at UC Davis. “You are putting highly condensed carbon in the soil, so that biochar itself has a longer residence time that just putting a piece of wood, or any raw biomass, in the soil. The fact that biochar is a fairly recalcitrant form of carbon means that microbes cannot utilize it easily as food source and carbon dioxide emissions are thus temporarily reduced. However there is also a lot of excitement around the potential of biochar to also provide a host of specific agronomic benefits.”

But as a relatively young avenue of scientific research, conclusive evidence of its benefits is largely inadequate. To drive forward the understanding of biochar, Parikh, along with postdoctoral scholar Fungai Mukome have created the UC Davis Biochar Database — a forum dedicated to comparing the physical and chemical properties of biochar based on the various sources used to make them, and through that generate a broader understanding of the replicable benefits biochar can bring to soil.

“With our database we’re hoping to provide some of the basic data to the biochar community to link these benefits with specific biochar feedstocks and processing temperatures,” Parikh said.

The database, funded in part by the Agricultural Sustainability Institute at UC Davis, can be used as a resource for biochar researchers, manufacturers and users to better understand the effect that different biochars have shown in soil. Users can begin to tailor their biochar systems to better reflect the advantageous results that have been shown in biochar research. And for those studying the benefits of biochar, the database serves as an open source community that biochar researchers can add to in order to develop a comprehensive guide to the research.

“We released the database with 80 entries, and currently have over 300, but our goal is to grow the database to include 1,000 entries within a year,” Parikh said. “There needs to be a place to come to understand the properties of biochar, and opening the forum for community contributions is an important way to expand our knowledge.”

The biochar database can be visited at biochar.ucdavis.edu and contains instructions on how to download data, and how to contribute to the database by uploading data on biochar chemical and physical properties.

Posted on Thursday, July 18, 2013 at 9:22 AM
  • Author: Aubrey White

Bodega Marine Lab keeps watch on ocean temperatures

Ocean waters are warming, sea level is rising, seawater is becoming more acidic, and shoreline erosion is intensifying. The world’s oceans are reacting to increased carbon dioxide and other greenhouse gases in the earth’s atmosphere.

“The physical and chemical environment of the ocean is changing with the climate,” said John Largier of the UC Davis Bodega Marine Laboratory. “This affects ecosystems — like tidal marshes and coral reefs that protect us from storms and flooding.”

The ocean brings stability to the earth’s climate. It heats up and cools down more slowly than the land and the air. With climate change, the ocean absorbs excess heat trapped in the earth’s system by the increased concentration of gases in the atmosphere.

As seawater warms, it expands. The increase in the ocean’s heat content has contributed to one of the most visible effects of global warming — rising sea level. Thermal expansion, along with melting polar ice caps and glaciers, has led to global sea level rise of more than seven inches over the last century.

“When the ocean begins to warm up, then you know that the earth’s climate is changing,” said Largier, a professor in the Department of Environmental Science and Policy. “Even if we stop putting greenhouse gases into the atmosphere right now, the ocean has warmed up, and it will take centuries for it to cool down. People don’t realize that we’ve already made a long-term commitment to climate change.”

At the Bodega Marine Lab, Largier and other scientists are studying the regional impacts of climate change on the waters off California, which include an increase in coastal upwelling. Driven by winds, upwelling pulls cold water and nutrients from the ocean depths to the surface along the shore and contributes to the “marine layer,” the blanket of cool moist air that moderates California temperatures. Largier’s research shows a trend toward stronger winds and an increase in upwelling since 1982, leading to cooler waters off central and northern California.

“Worldwide, the ocean’s surface water is getting warmer, but in California, the ocean is getting colder near shore,” said Largier. “This is intriguing because it shows that climate change is not going to have the same effect everywhere. There will be regional differences.”


This article was condensed slightly from UC Davis “CA&ES Outlook” magazine. Read the full article on page 7.

Read John Largier's scientific advisory group report on how changes in the ocean might affect two valuable marine sanctuaries off the northern California coast: "Climate Change Impacts: Gulf of the Farallones and Cordell Bank National Marine Sanctuaries"

John Largier along the northern California coast. (Photo: Jennifer Sauter/UC Davis)
John Largier along the northern California coast. (Photo: Jennifer Sauter/UC Davis)

Posted on Wednesday, May 22, 2013 at 1:51 PM

UC Davis voted America’s “coolest” school

After just experiencing my first Davis summer, I find it hard to describe anything in Davis as cool. But according to Sierra Magazine, UC Davis is just that. So much so, that the school was recently named the #1 Coolest School in the nation. Granted, they weren’t talking about the weather. Instead, they were referring to UC Davis’ environmental stewardship.

With all that UC Davis does to create and promote environmentally friendly programs and facilities, it’s no wonder the university just received this high honor. The campus is on track to reduce campus greenhouse gas emissions back to 1990 levels by 2020 and reduce campus electrical use by 60 percent by 2015.

Bicycles on the UC Davis campus.
UC Davis also provides sustainable forms of transportation to 85 percent of students and 46 percent of employees. As a fairly new Davis resident, I’m still constantly blown away by the number of bikes on campus, especially during the first week of school. Being from Long Beach, I always feel a pang of culture shock watching the Davis police handing out bike traffic violations instead of combating violent gang activity.

In 2011, UC Davis encouraged recycling, composting and reuse efforts that prevented 64 percent of campus waste from entering landfills. Sierra Magazine praised the university for its green purchasing, spending more than 20 percent of its $5.6 million food budget on local and organic products.

UC Davis also received international attention last fall, when it officially opened the doors to UC Davis West Village, the nation’s largest planned zero net energy community.

“At UC Davis, sustainability is one of our core values,” said UC Davis chancellor Linda P.B. Katehi. “I am very proud of the students, faculty and staff who have worked so hard to make this achievement possible and to invest in a more sustainable future for our campus.”

Other California schools that made the top 10 included Stanford University at number 3, and UC Irvine at number 9. California had the highest contingency of schools in the top 10 list.  

Congratulations to UC Davis, for earning the title of Coolest School in the middle of this summer’s heat!

Watch this Sierra Club video highlighting UC Davis’ green achievements to learn more:

Posted on Wednesday, October 10, 2012 at 8:51 AM
  • Author: Marissa Palin

Switchgrass could become high-yielding biofuel crop

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 second year of production, switchgrass in El centro yielded 17.6 tons per acre, and productivity tends to increase through the third and fourth years.
However, the overall cost of producing and transporting corn ethanol is significant, both in dollars and greenhouse gas emissions. Whether average corn ethanol reduces greenhouse gas emissions is a matter of dispute, as the GHG that result from its production and transportation to customers may cancel out the hoped-for reduction in carbon footprint.

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 of switchgrass' high biomass yields, it is considered a good candidate for dedicated energy crops.

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.

Posted on Wednesday, August 10, 2011 at 8:34 AM
  • Author: Janet L. White
Tags: AB32 (2), biofuel (6), cellulose (1), global warming (8), greenhouse gas (4), switchgrass (2)
 
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