It's the Soil Research shows that getting ground back in balance by encouraging the development of beneficial microorganisms can provide a big boost to plant health
-By Grace Ertel
Recent political campaigns used the slogan, "It's the economy, stupid" to focus on what was considered essential. In agriculture, all the chemicals and other unnatural substances added to the soil during the past 50 years have caused some ground to become almost sterile.
New experiments using a friendly invasion of beneficial fungus have been found to give a big boost to the root systems of crops. Paying attention to the soil, it seems, is essential and yields great benefits.
So why has fungus always had such a bad name? Perhaps it's because most people notice the fungus on plant leaves, which can be bad, and are not as aware of the good fungus underground.
Within the soil is a fungal species known as Mycorrhizae, which has a symbiotic relationship with plants and lives on the carbohydrates they supply. In turn, the fungus enhances the plant's root system, resulting in increased uptake of water and nutrients. In other words, the fungi and plants practice the "you scratch my back, I'll scratch yours" approach to life.
This Mycorrhizae is the most common soil fungus on earth and is older than mankind. It's present in most soils, so why should farmers be concerned? According to Robert Linderman, a research plant pathologist for the USDA's Agricultural Research Service (ARS) in Corvallis, Oregon, "If our crop plants, other than those that are non-mycotrophic [lack Mycorrhizae], it is probably because the detrimental effects agricultural and forestry practices have had on these fungi."
This is particularly true in vineyards, where many growers rely on fumigation, which practically sterilizes the soil, to guard against phylloxera and other pests and diseases in replanted vines. Bob Shaffer, certified crop advisor with Native Cultures of Glen Ellen holds that there are better ways to cope than using fumigation or systemic fungicides. For example, there are cultural practices such as pulling the infected leaves and using a trellis system that keeps grape vines up in the air and less fungus-prone. However, the primary method is to have healthy soil.
"The term 'healthy soil' is rather new to a lot of people," Shaffer says. "When we look at a clod of soil after the rain, we'll see a tremendous amount of bacteria or blue-green algae. These are photosynthetic plants that are microscopic. All the micro flora are part of the biomass. That's what we mean when we talk about soil being healthy- not the minerals. The minerals we balance."
Shaffer relates how Elaine Ingham, professor of soil ecology at Oregon State University, explains healthy soil to farmers. "We have the equivalent of one Holstein cow living in each square meter [about a whole herd in an acre] depending on how much humus we have. Have we paid attention to it, fed it, cared for it? Humus is where living organisms like to live."
Shaffer says the whole agricultural industry is reevaluating the wide use of synthetic, or more specifically soluble fertilizers, which are inexpensive, very potent and can leach easily. "When these were first developed, the potency was very low but the idea was to reduce the volume in order to ship them more economically. Then the grades went from 3% to 15% per volume. As the farmers saw how fast things grow, they started to overuse them."
"When we add large amounts of sulphur, phosphate, nitrogen or whatever, we can imbalance the soil and cause illness. It's only been 50 years or so since we've been able to get into so much trouble."
Now, he believes the trend is to use cover crops for fertilizers along with slow-release rock phosphates, limestone's, and dolomite. "When the farmer has used a lot of herbicides, we find the soil under the vines is much less healthy there. I can feel it with the soil compaction measuring tool. The Mycorrhizae has been compromised and the whole vine suffers. We need to use mechanical tillage to hoe/plow the weeds. We grow a combination of plants between the rows, mow them and blow them up on the burn much as we mulch in our gardens. Then we add good quality, disease-suppressing compost to the soil. Our goal is to feed those Holstein- that is, to feed the fungi."
"We found phylloxera on the roots of these 40-year-old vines," Shaffer says of vines at the Wood Vineyard on River Road in the Russian River Valley appellation. "They will still produce good grapes but we decided to go to a rootstock that would serve us better."
They've planted a new stock using BioVam, an inoculant with Mycorrhizae, nitrogen-fixing bacteria, nematode-trapping fungi, humic and folic acid, minerals and other ingredients to give the transplants the best start. According to Shaffer, the plants are inoculated in the field, the roots soaked in kelp and planted between the rows of the old stock, which will eventually be replaced. Rape plant, safflower, mustard and daikon radish are used as cover crops to put roots down in the soil and break up compaction. They also capture nitrogen and give some nematode protection. "These are all things we've done in the 20 or so years I've been in this business- things we know tho work," he says.
Alexander Hogstrom, general manager of Alden vineyards in Geyersville, is also enthusiastic about mycorrhizae and its function in the soil. The 1,500 acre Alden Ranch has 210 acres in wine grapes, the oldest of which were planted in 1988. The chief challenge on the ranch is the hillside development that requires extensive grading.
"This disrupts the subsoil and at 1,400 foot elevation, the soils are very shallow and rocky," he says. "So even if we don't fumigate after grading and trying to put the soil back, we're left with an unproductive land where even some cover crops have a hard time growing."
Hogstrom, who has been with Alden Vineyards since 1994, has put in many acres of new grapes but in some areas he found the crops "just sit there." Then, several years ago at a grape growers seminar, he heard a talk by Brock Probiotics, inventor and manufacturer of BioVam, who gave a presentation on introducing a Mycorrhizae-enriched soil to the rooting zone when grapes were transplanted.
In the spring of 1996, Hogstrom began planting new vineyards using BioVam, a commercial Mycorrhizal inoculant. "I called Brock Probiotics, gave a physical description of the soil and the native vegetation we had before and the cover crop," he says. "Then we tailored the right mix for here. It took just one extra employee to add a tablespoon full of the mix to each plant when putting in a new vineyard.
"Now my employees have remarked that these new plants have the easiest and best establishment of any we've had. Many vines were up to the trellis wire (36 inches) in less than a year where formerly it took three years," Hogstrom says.
Hogstrom believes paying attention to the soil is most important and says soil on the floor of a forest feels fluffy- alive with organisms- whereas the soil in much agricultural land these days feels lifeless. "If there is a way to add Mycorrhizae to the established vineyards, I'd surely do it," he says.
Raisin growers Wayne and Kathy Smith of Shafter have reason to praise the BioVam inoculant for saving their vineyards when an irrigation system failed during their absence. When they watered again, they found 90% of the inoculated vines came back in production and outperformed many others while only 50% of the non-inoculated survived.
Brock Probiotics, a vocational horticulturist with 20 years experience, formulated BioVam-GI, a biological inoculant, and manufactures BioVam in Thousand Oaks. According to Brock Probiotics, his research took him to five foreign countries to collaborate with scientists. He recently returned from China, where a factory is being built to produce BioVam. The Chinese now must import their grain and are anxious to enhance their crops without damaging soil fertility. Other countries, including India, Morocco, Spain and Italy, have also expressed interest.
In addition to grapes, where Brock Probiotics research revealed a 20% to 2,600% increase in growth on vines planted on fumigated soils, other crops have also benefited. Additional research shows that use of the inoculant increases production in all row crops- especially tomatoes, squash, melons, strawberries and onions- with the exception of the cabbage family, which seems to rely less on the fungi.
Although Brock Probiotics admits the super phosphates may be cheaper to apply, they can pose a danger to groundwater and farmers will find them more difficult to use as the government continues to enforce the Clean Food and Water Act of 1997. However, many farmers who adopt a biotic program are finding they are able to lower their nitrate use as much as 50% as well as decrease phosphates. A new category was created in the California code governing the registration of all agricultural food crops when BioVam was registered as an Auxiliary Soil and Plant Substance. Brock Probiotics claims to be the first to produce the inoculant in significant amounts for commercial application and deliver it in an environment in which it thrives.
According to Brock Probiotics, the company is currently working with root-stock nurseries to encourage inoculating the root stock before planting. One such nursery, Duarte in Northern California, is now testing this procedure. Brock Probiotics is also researching ways of introducing the inoculant into a drip system as a way to reach established plants more economically.
There's also good news at Linderman's office at the ARS facility at Oregon State, where a research assistant says that office, too, is working on the problem of introducing the fungi to the roots of established plants and may soon publish their findings. According to Linderman, "Mycorrhizae are the orchestrator of everything that happens. You cannot name any other single organism in the root zone that has as much potential to influence plant or root growth than these fungi." In other words, we should pay attention to the soil- it's what sustains us."
Reprinted with permission from California Farmer, November 1997.
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