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California Climate and Agriculture Network Farm Field Day

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Earl’s Organic sponsored the Soil Building, Water, Biodiversity and Climate Change Farm Field Day, part of the California Climate and Agriculture Network (CalCAN) Farming For The Future 2013 Summit February 20-21 at UC Davis. UC Davis was originally designed as a farm school and students were called “aggies”. I am an aggie and was very excited to be back visiting my alma mater.

CalCAN is a coalition that works to advance policies to support California agriculture in the face of climate change. They advocate that agriculture can play a proactive role in responding to the climate crisis by reducing its carbon footprint and thus helping to ensure the long-term viability and security of our food and farming system.  Retrieved from http://www.calclimateag.org

One third of global CO2 emissions come from agriculture and land use changes such as forest clearing. Fertilizer applications account for most all of the world’s nitrous oxide emissions (a greenhouse gas 298 times more potent than CO2), and agriculture contributes two-thirds of all methane emissions (25 times more potent than CO2). California, with a huge agricultural economy is the twelfth largest producer of greenhouse gas (GHG) emissions in the world, and agriculture is responsible for six percent of GHG emissions in California, according to the Scoping Plan pursuant to California’s Global Warming Solutions Act (AB 32).  Retrieved from http://www.calclimateag.org

I personally love growing vegetables on my small front porch but I didn’t have an intricate knowledge and understanding of the essential roles nitrogen and carbon play in the growing process.  Nitrogen is one of the most important nutrients for crop growth and carbon is needed to increase crop productivity and enhance soil and water quality.  However if there is too much nitrogen and carbon released into the atmosphere this can cause a greenhouse effect we all know as global warming.

While at UCD we toured 2 working farms and a research facility where we witnessed how agriculture practices can affect climate change and what farmers and researchers are doing to reduce the industry’s carbon footprint.

Farmers use many techniques to slow down the effects of climate change including cover crops, composting, planting trees and reducing synthetic fertilizer use and tillage. These techniques can help store large amounts of greenhouse gases in the ground, potentially reducing the growth of GHG levels and at the same time improve water quality, increase soil fertility and agricultural productivity. We were able to see some of these practices at work as we began our tour.

We started at The UC Davis Student Farm where Mark Van Horn, Student Farm Director, showed us both the student Market and Ecological farms. The students sell the produce grown on the Market farm at farmers markets and the UCD Coffee House to raise funds for the Market production.  The farms are certified organic and focus on teaching a wide diversity of skills year round including direct seeding and transplanting of crops, growing transplants in the greenhouse, field preparation, irrigation, cultivation, pest management, harvesting, packing and marketing.  They have an average of about 150 students which fluctuates based on the season. The Ecological garden is a half-acre with flowers, vegetables, herbs, fruit trees and chickens. It provides an opportunity to teach students, grade school students and adult visitors about ecological horticulture.


Nodules on nitrogen producing plants

Both farms use compost and cover crops to improve the quality of the soil.  Compost contains nutrients not found in synthetic fertilizers which can improve plant health and growth. It also helps improve water drainage and holding capacity and reduces erosion.  A huge pile of compost largely consisting of sheep manure borders the Market garden.  The compost, rich in organic matter, has to be kept at a minimum of 130 degrees for a specific amount of days in order to be used on the fields. (pic)

Cover crops are used to improve nitrogen content in the soil, contain weeds, protect soil from runoff and suppress soil diseases and pests. Nitrogen is vital for plants but most nitrogen is available only in gas form which most plants can’t use.  Cover crops, such as legumes are used because they can take the nitrogen from the air and store it in their roots. Nitrogen fixing plants need help from Rhizobium, a bacteria that affects legume plants, in order to take in the nitrogen and store it. The nitrogen causes lumps on the roots to form called nitrogen nodules.  Only a little nitrogen goes into the soil while the cover crops are growing but when they die the stored nitrogen is release into the soil rather than the atmosphere. Mark pulled up some legumes to show us the nodules in the roots where nitrogen is contained. (pic)

Our second stop was Russell Ranch Sustainable Agriculture Facility with over 300 acres dedicated to agriculture research in a Mediterranean climate.  Their largest and longest research project is a 100 year old study started in 1993 to measure the long-term impacts of crop rotation farming systems and the inputs of water and nitrogen on agriculture sustainability.  There are 72 one acre plots with a mix of conventional, hybrid(conventional with cover crops) and organic systems.  The crops include alfalfa, corn, native grasses, tomato, wheat and sunflowers. The researchers and students measure crop yields, crop nutrient levels, soil quality, biodiversity, greenhouse gas emissions, water use and economic returns for each plot. One of the largest questions is “Can we increase our sustainability as we increase our food production?”

Click here for a short video of Russell Ranch.

Another study at Russell Ranch investigates the impact of biochar applications on soil carbon, soil microbiology and greenhouse gas emissions.  Biochar is charcoal that is used for agricultural purposes and is a way to remove carbon from the atmosphere and store it in the soil for a long time. It is made from organic biomass such as manure, wood or agricultural byproducts. It is spread on the fields and then worked into the soil to help increase crop yields, help to prevent fertilizer runoff and leaching, replenish soil with organic carbon, and encourage the growth of soil microbes essential for nutrient absorption.

Click here if you are interested in learning more about how biochar is produced.

Our last stop was Sierra Orchards, a 450 acre organic walnut orchard started in 1980 in Winters, CA right next to Davis.  Originally, 325 acres of the land grew tomatoes until 1997 when the walnut trees were planted.  Craig McNamara, owner, farmer and environmentalist, uses sustainable practices in all aspects of the farm.  Over half of the fertilizer is derived from cover crops and the rest is from compost. He doesn’t use tillage, has planted hedge rows to create a habitat for pollinators and uses drip irrigation which is the most effective way to conserve water. He wants to have the type of agriculture that positively impacts people who farm, the planet, and farm profitability.


Craig McNamara from Sierra Orchards in Winters, CA

Putah Creek nearby is an important part of the conservation efforts on the farm.  Recently they have narrowed and deepened the creek to make a faster rushing stream. Ideally they would like this to be a place for migrating fish like salmon.  His goal is to work with nature; Craig says “farmers just want best management practices”.

Sierra Orchards is also a state wide center for land based learning with over 2000 students and 5000 visitors a year. He wants the next generation to be well versed in sustainability so they share what they have learned and have a deep connection to the land.

While numerous farmers, academics, and policy makers have made huge strides in recent years in discovering new techniques for reducing the GHG impact of agricultural production, there is much work still to be done.  The question still remains: How can we disseminate these larger techniques into large scale commercial agriculture to ensure the long term viability of our food systems and reduce the environmental impact of the agriculture industry?  There is no easy answer but I have never met a group of people more dedicated to coming up with ways to solve the problem.

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