Bio Huma Netics, Inc.

Saying Goodbye to Soil Fumigants

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2 Saying Goodbye to Fumigants 800.961.1220 growers, for example, saw their yields nearly quadruple in the decades after fumigants were first used, and many growers attributed this success to fumigant use. Advances in Understanding Soil Microbiology In addition to the long-known negative health effects of soil fumigants, more recent developments in the understanding of the importance of biodiversity in crop soil has led many to believe that the use of soil fumigants damages the long-term sustainability of crop soil. Fumigants kill almost everything in the soil, including the beneficial bacteria, fungi, and other microorganisms that keep the soil healthy. In recent years, we have developed a much better understanding of plant-microbial interaction. Soil microorganisms break down nutrients and provide them to plants in a form that the plants can more easily use, they help protect plants from many types of predators, and they provide a soil structure that is beneficial to the absorption and flow of necessary gases and water, improving plant respiration and hydration. When soil fumigants sterilize the soil, they not only kill off all the beneficial microorganisms, they also set up conditions that make the soil and crops more vulnerable to future pest invasions. In healthy soil, biodiversity helps to control damaging pests by giving them competitors that "out-eat" and "out-survive" them. When the good competitors are killed off in fumigation, the door is left wide open for the damaging pests to come back stronger than ever (hence, the year-after-year applications). Also, without the beneficial microorganisms being available to provide nutrients to plants in a form that they can easily consume, growers are forced to increase the amount of fertilizers and pesticides they use to sustain previous yield levels—increasing inputs but decreasing productivity. Sustainable Alternatives So, with fewer effective soil fumigants available and costs rising to meet the restrictions associated with fumigant application and use, what alternatives do responsible growers have if they want to grow premium crops in a cost- effective AND sustainable way? They begin by providing sound soil stewardship that puts the soil microorganism ecology, or "microbiome," back in balance. Soil fumigants were tantalizingly easy for growers to use because one application process had so many good immediate outcomes. To replace fumigants, though, is likely going to require multiple practices that may change as individual crop-growing circumstances change. Some of these practices include: • Using Disease-/Pest-Resistant Varieties of Cultivars: these are available for some crops but not for others. We expect them to be more available in the future, so growers should always be on the lookout. • Green Manures: Certain crops (e.g., Brassica) that are incorporated into the soil before they reach maturity have proven effective in managing specific pests, such as nematodes. Sweet corn used as a green manure has proven effective in suppressing Verticillium wilt in potato fields. The addition of organic matter into the soil in general has a positive effect on yield in its own right. • Soil Solarization: placing plastic sheets over moist soil during periods of high temperature can kill many disease-causing organisms, nematodes, and weed seeds; however, this practice is most effective only in hot, dry climates. • Crop Rotation: depending on the target crop, there are rotational crops that can play an important role in an integrated pest management strategy. Rotating wheat and/or barley with potatoes, for example, allows growers to apply nightshade-weed herbicides to the rotated crop, since they cannot be used directly on potatoes. • Using Nematicides/Fungicides: Sometimes using harsh soil fumigants is "overkill" when all that is needed is an effective nematicide/fungicide, particularly when paired with some of the other practices outlined above. This last practice area is where Huma Gro ® can help, with its combination of Promax ® (an OMRI-Listed broad-

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