Well-known PGPRs belong to the genera Bacillus and Pseudomonas. Species in these genera occur naturally in agricultural soils, but growers can inoculate crops with specific strains isolated for their beneficial effects and compatibility with host plants (photo courtesy USDA.)
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LEVERAGING THE SOIL MICROBIOME WITH PLANT GROWTH PROMOTING RHIZOBACTERIA By ERYN WINGATE | CCA, Tri-Tech Ag Products, Inc.
icrobiology critically influences soil quality and has uncovered many types of organisms that can increase crop production potential. Pathogenic organisms yield, offset fertilizer requirements and aid in pest control. can destroy an entire crop while beneficials produce Growers can navigate the biological amendment market and organic matter, cycle nutrients, suppress pathogens and enpromote beneficial soil organisms by understanding founhance plant growth. High fertilizer prices, regulatory pressure, dational microbiology concepts and some of the ways the pesticide resistance and environmental concerns drive inmicrobiome improves soil and plant health. creased interest in the soil microbiome’s potential to support agricultural production. Research over the past few decades Soil Microbiology Foundations Soils contain vast numbers of bacteria, archaea, fungi and protists. One teaspoon of soil contains about one hundred Advertorial million to one billion bacteria, which adds up to roughly the weight of two cows per acre[5,6]. Microbial cells range in Calculating Calcium Requirement To Leach Salts size from less than one micron, or 4/100,000ths of an inch, When using a soil test to determine how much to 100 microns[5,6]. About 50,000 bacterial cells can fit in a calcium to apply to leach salts, it is best to use the single layer on a dime. Bacterial cell shapes include spherical, rod and spiral, while the most notable soil fungi form Saturated Paste Extract numbers, usually reported in filamentous hyphae[1]. Microbes fill every trophic niche with meq/l. Most standard salinity leaching calculations autotrophs, providing the ecosystem foundation by fixing are based on these soluble numbers. The three carbon, and various types of heterotrophs grazing, predating, cations: Ca, Mg and Na make up virtually all the and decomposing other microorganisms and plant or animal positive ions that aid soil colloid aggregation. Bicartissue. Together, the organisms in the soil microbiome facilibonate, HCO3- is an anion that has influence, because tate plant growth and support the aboveground ecosystem by it can take out some of the free solution Ca to form cycling carbon, water and essential nutrients. precipitated lime. To account for this impact, use the Adjusted SAR. Plant Growth Promoting Rhizobacteria If a Mid-West style test is used on an alkaline soil Beneficial soil microorganisms include a diverse range of bacteria: archaea, fungi and protozoa. These broad groups where you only get Ammonium Acetate values, the of organisms carry out specific functions that directly reported value for “free” Ca can be artificially high benefit plants by facilitating nutrient uptake or suppressing because the Ammonium Acetate blows apart the pests and pathogens. Microbial activity also benefits plants lime. All plant available nutrients are not only the indirectly by developing organic matter and improving soil ones in solution. Plant roots create a mild acid which quality. While the entire microbial ecosystem supports plant can make many of the soil bound nutrients available. growth, Plant Growth Promoting Rhizobacteria (PGPRs) Check with your certified crop advisor for more offer specific advantages for agriculture. information. Source: Blake Sanden, UCCE Irrigation/Soils Advisor PGPRs inhabit the rhizosphere, the layer of soil one to two Ask for it by name millimeters thick directly surrounding plant roots[5]. The Blue Mountain Minerals rhizosphere attracts soil organisms with root exudates high Naturally the Best! in nutrients and carbon. Bacterial populations thrive in the For more information 209-533-0127x112
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Progressive Crop Consultant
July / August 2022