The following research article developed by BioFlora’s team at the Integrated Life Science Research Center describes the clear benefits of rejuvenating your soil after depleting it with fumigation. Please share it with your PCA or call your BioFlora representative to arrange a visit or virtual GoToMeeting with our talented team if there are any further questions.
The problem facing many growers is the loss of soil microorganisms after fumigation. Common fumigants like methyl bromide, chloropicrin, Telone and others have been shown to destroy beneficial microbial populations in the process of removing soil borne pathogens and pests.
This recovery period for soils may last from weeks to months, and some soil microbes never recover. There is also strong evidence of less and less microbial recovery the more a fumigant is used.
After fumigation, there are many microbial “home sites” in the soil that are empty and need to be filled. This is a chance to repopulate the soil with beneficial microbes. Not doing so results in lower microbe diversity and the potential overgrowth of damaging microbes that survive fumigation.
GO Isolates is an ideal choice after fumigation because it supplies a high diversity and population of beneficial soil microbes, including bacterial strains that protect plant and root defense systems. GO Isolates contains a diversity of carbon complexes that support the improved microbial community when applied to the soil.
Loss of Soil Microbes due to Fumigation
Beneficial microorganisms in the soil are essential for sustaining the health of agricultural soil systems. These soil microbes make significant contributions to pathogen suppression, nutrient cycling, plant nutrient uptake, soil structure development and maintenance, and agricultural productivity. When the beneficial microorganisms are depleted or missing from the soil, there is:
Fumigation with methyl bromide (MeBr), chloropicrin (CP), Telone and others is used to control a wide-array of soil borne pathogens and pests. While there is variation in the impact of the fumigant to nontarget microorganisms, all fumigants destroy a portion of the beneficial microbial population.
Various studies, both in the laboratory and in the field, have found that all major nontarget groups of soil microbes are significantly impacted by MeBr and MeBr:CP. Soils fumigated with MeBr typically have a longer recovery period than those fumigated with Telone.
The recovery time for soil microbial community structure after fumigation extends for many weeks or months (a significant portion of the crop cycle) and some microbial groups never recover to the levels found before fumigation.
The soil microbial community biomass is significantly lower in fumigated soils at depths up to 30 cm (12 inches). Additionally, there is strong evidence of less and less microbial recovery the more years the fumigant is used.
Apply Beneficial Microbes to the Soil
GO Isolates is an OMRI and CDFA listed product that contains a wide diversity of native beneficial soil microbes in addition to a complex of carbon diversity to support the microbial growth after the microbes are in the soil.
Studies have indicated that there is a difference in deleterious and beneficial rhizosphere colonizers following fumigation in strawberry rhizosphere fumigated and non-fumigated soils. This emphasizes the need to replenish the soil with beneficial soil microbes before the harmful microbes can colonize the plant roots.
A nitrogen flush is frequently observed after fumigation, the result of decomposition of the cells killed by the fumigant, which is used for recolonization of the soil by the survivors of the fumigation. There are many empty microbial “home sites” in the soil that are vacant and need to be filled.
This is a prime opportunity to supply the soil with beneficial microbes to repopulate the soil. Not doing so results in a lower diversity of microbes and potentially the overgrowth of undesirable microbes that are fumigant survivors. Additionally, these microbes require a carbon source for food.
The GO Isolates product is an ideal source for supplying agricultural soils with both a diverse beneficial microbial population as well as the diverse carbon complexes needed to support them once they are in the soil. The suggested application rate for GO Isolates is 10 gallons/acre applied 3 times after fumigation at 2-4 week intervals.
Within the Global Organics Group, the Integrated Life Science Research Center® (ILSRC) works as the research and development arm of leading plant health division BioFlora®, and human and animal health division, Mineral BioSciences®. As such, the ILSRC investigates a wide variety of subjects, including: agronomy, microbiology, chemistry, plant pathology, and human and animal physiology, just to name a few. To support these markets, the vision of the ILSRC is to promote and develop sustainable practices, products, and services by utilizing pioneering techniques, disciplines, chemistry, and methodology. For more information about Global Organics Group, or to interview CEO and Managing Partner Luke Blotsky, please contact Sarah Van Wyk at firstname.lastname@example.org or visit www.globalorganicsgroup.com.
References and Supplemental Reading
1. P.C. Brookes, A. Landman, G. Pruden and D.S. Jenkinson, “Chloroform fumigation and the release of soil nitrogen: A rapid direct extraction method to measure microbial biomass nitrogen in the soil”, Soil Biology and Biochemistry, vol. 17. no. 6, pp. 837-842, 1985.
2. S.R. Dangi, J.S. Gerik, R. Tirado-Corbalá, and H. Ajwa, “Soil microbial community structure and target organisms under different fumigation treatments”, Applied and Environmental Soil Science, vol. 2015, article ID 673264, 8 pages.
3. S.R. Dangi, R. Tirado-Corbalá, J.S. Gerik and B.D. Hanson, “Effect of long-term continuous fumigation on soil microbial communities”, Agronomy, 2017, 7, 37, doi:10.3390/agronomy7020037.
4. A.M. Ibekwe, S.K. Papiernik, J. Gan, S.R. Yates, C.H. Yang and D.E. Crowley, “Impact of Fumigants on soil microbial communities”, Applied and Environmental Microbiology, vol. 67, no. 7, pp. 3245-3257, 2001.
5. F.N. Martin, “Development of alternative strategies for management of soilborne pathogens currently controlled with methyl bromide”, Annual Review of Phytopathology, vol. 41, pp. 325-350, 2003.
6. E.H. Ridge and C. Theodorou, “The effect of soil fumigation on microbial recolonization and mycorrhizal infection”, Soil Biology and Biochemistry, vol. 4, no. 3, pp. 295-305, 1972.
7. T. Yamamoto, V.U. Ultra Jr., S. Tanaka, K. Sakurai and K. Iwasaki, “Effects of methyl bromide fumigation, chloropicrin fumigation and steam sterilization on soil nitrogen dynamics and microbial properties in a pot culture experiment”, Soil Science and Plant Nutrition, vol. 54, pp. 886-894, 2008.