Benefical Of The Month: Beneficial Microbes
July 1, 2009 Biological Benefits
Farmers often think of microbes as pests that are destructive to their crops, but many microbes are beneficial. Soil microbes (bacteria and fungi) are essential for decomposing organic matter and recycling old plant material. Some soil bacteria and fungi form relationships with plant roots that provide important nutrients like nitrogen or phosphorus. Fungi can colonize upper parts of plants and provide many benefits, including drought tolerance, heat tolerance, resistance to insects, and resistance to plant diseases.
Biological complexity of a soil system can affect processes such as nutrient cycling, the formation of soil structure, pest cycles, and decomposition rates. Many different soil microorganisms are responsible for nutrient recycling (for one, through decomposing plant residues) and other soil-building and soil-maintaining activities. They also play a positive role in nutrient retention, improved soil structure, water infiltration, water-holding capacity, degradation of pollutants, and disease suppression.
A complex soil/food web contains numerous organisms that can compete with disease-causing organisms. These competitors may prevent soil pathogens from establishing on plant surfaces, prevent pathogens from getting food, feed on pathogens, or generate metabolites that are toxic to or inhibit pathogens.
EM Technology
Dr. Teuro Higa, at the University of Ryukyus, Okinawa, Japan has pioneered the use and introduction of beneficial microorganisms in cropping systems. He introduced the term “effective microorganisms” (EM) to describe a type of technology using beneficial and effective microorganisms.
There are more than 80 strains of microorganisms that have been identified as having beneficial characteristics. EM uses mixed cultures of beneficial microorganisms such as photosynthetic bacteria (Rhodopseudomonas sp.), lactic acid bacteria (Lactobacillus sp.), yeast (Saccharomyces sp.), and fermenting fungi to positively improve the soil fertility as well as enhance plant productivity and disease suppression.
Products For Production
Other products based on the use of beneficial microorganisms have come into play in vegetable production in recent years. Examples are SoilGuard (Certis) for disease suppression and growth enhancement, Melocon (Certis) for nematode control, and Serenade and Sonata (Bacillus subtilis, Bacillus pumilus, AgraQuest) for foliar disease control.
As growers seek to reduce production costs and enhance productivity and sustainability, attention to soil building, a greater understanding of soil ecology and diversity, and the use of beneficial microbes may play an increasingly important role in the future of crop production and integrated pest management.