Mary Matava dug her hands deep into a massive pile of warm dirt and showed off the goods: microscopic organisms digesting green waste, and giving off loads of steamy carbon dioxide.
LAURA EMBRY / Union-Tribune
David A. Loring, a soil conservation expert working with Tierra Miguel Foundation farm, talked to farmers about the benefits of mulch last week at a workshop at the Pauma Valley farm. Soil studies show that using mulch can help reduce water costs, Loring said.
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“That's how you know it's working,” Matava said, feeling the warmth on her palm.
For 12 years, she has perfected composting at her Oceanside company, El Corazon Composting, which offers everything from rich dark organic matter to woodsy brown mulch. The plant has grown from producing 10,000 tons of soil additives its first year to about 80,000 tons today. It is used by landscapers, homeowners and some farmers.
“It's taken a lot of marketing” to grow such demand for compost, Matava said.
But agriculture and county officials are scratching their heads. They are trying to figure out how to get more people, especially farmers, to embrace the benefits of compost and other natural waste, and to use more of it.
“We have this mindset of letting this wonderful resource go to waste, when we could be using it to consume and grow better food,” said Wayne T. Williams, San Diego County recycling coordinator.
The push for farmers to use recycled green waste comes as San Diego County faces a seemingly endless supply of dead trees from mountains in the wake of the 2003 fires. Palomar Mountain and the Lagunas easily have “thousands of tons” of mulch from felled trees that will be available for the next few years, Williams said.
Unlike other counties where mulch has been trucked to landfills, San Diego officials want to make sure the mulch off the mountains is spread outdoors, or burned as a last resort. Officials are appealing to North County farmers because farmers, with their large plots of land, could have a greater effect than home gardeners.
At a workshop for farmers sponsored by the county and Tierra Miguel Foundation farm in Pauma Valley, last week, about 15 farmers listened to the benefits and possible side effects of using mulch.
Mulch is applied to the surface of a soil, and can be as simple as wood chipped from dead trees or construction leftovers, such as wood scraps. Mulch also can be as complex as nutrient-rich compost that has been made by allowing landscape or food scraps to decompose under controlled conditions.
Under those conditions, compost is turned and at times watered to give microbes and fungi moisture and air. The compost grows rich in nitrogen.
EDUARDO CONTRERAS / Union-Tribune
A front loader was used to fill a screener with composting material at El Corazon Composting in Oceanside last week. The screener separates the material into grades of compost that will be sold to the public. The company has seen demand for compost grow.
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Most mulch from the mountains is dry wood that if applied on soil eventually will decompose, but will do so slowly and initially may rob plants of nitrogen.
But the benefits of mulch can be great, said David A. Loring, a soil conservation expert working with the Tierra Miguel farm.
Besides soil health, the biggest factor drawing farmers to learn about mulch is saving on water costs. Studies on small areas of soil show that in the first few years of using mulch, water costs can decrease by up to 50 percent, Loring said.
Mulch works by catching rainwater and directing it to soil, and it protects moisture in part by keeping the soil from warming up too much.
“The results can be stunning,” said Dusty Rhodes, a farmer who manages a 100-acre orange and avocado grove in Ramona.
Using mulch has helped him save water and protect soil, Rhodes said, and now he is experimenting to see if mulch will help protect his avocado trees from root rot, as studies suggest.
University of California Cooperative Extension farm adviser Gary Bender was among the experts warning farmers to proceed with caution when using mulch.
Bender has set up a test in Pauma Valley to measure how much mulch should be applied on large agriculture plots for best results. So far, early results show 6 inches deep is too much, Bender said.
“We got no water release,” Bender said.
The testing also will measure sprinkler sizes, night versus day irrigation and whether mulch can hurt young avocado trees instead of helping them by initially robbing them of nitrogen.
Farmers could try products in small plots on their farms, experts said.
Matava, the compost expert, recommends farmers mix the mulch off the mountains with organic material, such as manure or young green waste, if they want to see real benefits.
Williams, the county recycling coordinator, said that could come soon, because his department recently introduced a proposal to the county Board of Supervisors to allow small farms to work together on composting. The goal would be small composting operations that don't disturb neighbors yet allow farmers to help each other.
The county has a Green Waste Recycling Guide available at its Web site listing places that offer compost and mulch. Go to www.sdcounty.ca.gov, click on Search and type in “green waste recycling.”
Elena Gaona: (760) 737-7575; elena.gaona@uniontrib.com
