U.S. Department of Agriculture scientists have found that a natural seed coating can protect alfalfa against some soilborne diseases. Alfalfa is a $10 billion-a-year crop in the United States, but producing it can be a challenge. Farmers in the Midwest often plant it early in the spring when the soil is cold and damp. That makes the seeds vulnerable to a number of soilborne diseases.
To minimize the damage, most alfalfa seeds are coated with a fungicidal treatment. But the treatment, mefenoxam, is ineffective against the pathogen causing Aphanomyces root rot (ARR), which is common to Midwestern soils.
Demand for organic alfalfa for organic dairy operations is also increasing, and alfalfa treated with a fungicide can’t be labeled as organic. Many organic dairy farmers would like to expand but may face a roadblock due to a lack of available organic feed, according to Deborah Samac, a plant pathologist in the Agricultural Research Service’s (ARS) Plant Science Research Unit in St. Paul, Minnesota.
Samac wanted to see if coating alfalfa seeds with a naturally occurring mineral would protect them from soil diseases, including ARR. The mineral, zeolite, comes from degraded volcanic rock, has antifungal activity and qualifies as an organic soil treatment. Samac also wanted to assess zeolite’s effects on the health of plant roots and beneficial soil microbes. Continue Reading →