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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Characterization and Interventions for Foodborne Pathogens » Research » Publications at this Location » Publication #312138
Title: On-farm produced microbial soil inoculants effects on bread wheat (Triticum aestivum) production

Author
item ENGLANDER, AARON - University Of Maine
item Douds, David
item MALLORY, ELLEN - University Of Maine

Submitted to: Biological Agriculture and Horticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2015
Publication Date: 7/16/2015
Citation: Englander, A., Douds, D.D., Mallory, E. 2015. On-farm produced microbial soil inoculants effects on bread wheat (Triticum aestivum) production. Biological Agriculture and Horticulture. 32(2):85-97

Interpretive Summary: One of the primary beliefs of organic agriculture is that a healthy population of soil organisms is essential to maintain sustainability of agriculture. Some techniques for adding micro-organisms to the soil are promoted without proper scientific testing of their efficacy. We compared plant growth responses to various microbial inoculants and compared that to growth in the presence of sterilized versions of the inoculants to test whether plant response was due to the organisms or the carry-over if nutrients found in the materials in which the organisms were produced. One inoculant tested was that of mycorrhizal fungi produced on-the-farm in a compost-based media. Plant response to this inoculum was not related to the residual nutrient content of the compost-based media. Another inoculant tested was “Indigenous Micro-organisms” (IMO), integral to the Korean Natural Farming technique. This inoculum is made by incubating a mixture containing horse manure. Experiments showed that plant response to this inoculum was due to the nutrient carry-over rather than the micro-organisms. These results demonstrate the need for careful studies to ensure farmers receive reliable tools for the sustainable production of healthy food.

Technical Abstract: The use of microbial soil inoculants in agriculture is of increasing interest among growers and scientists. Research on the efficacy and application of soil inoculants, especially on-farm produced inoculants, is limited. This study aimed to determine the effects of a commercially available arbuscular mycorrhizal fungus (AMF) inoculant, an on-farm produced AMF inoculant, and an on-farm produced indigenous microbial inoculant on bread wheat (Triticum aestivum L.) AMF colonization, biomass accumulation, nutrient uptake and recovery, and grain yield and protein in a containerized greenhouse experiment and 2 years of field trials. The impact of the inoculants was compared with their respective controls (sterilized inoculants), while levels of N, P, and K were equalized across treatments. Both AMF inoculants enhanced AMF colonization compared with their relative controls in a greenhouse potting mix containing unsterilized field soil, but only the on-farm produced AMF increased aboveground biomass and phosphorus (P) uptake and recovery. No differences were observed among inoculants and their relative controls in the field. However, the indigenous microbial inoculant (IMO+) increased wheat aboveground biomass, nutrient uptake, nutrient recovery and grain yield when compared with the mycorrhizal inoculants, but no increases were observed when contrasted against its control (IMO-). Therefore, wheat growth enhancements from IMO were likely due to nutrient supply from the compost-based material in which it was produced. Results demonstrate that a mycorrhizal inoculant produced on-farm can increase wheat AMF colonization, aboveground biomass and P uptake and recovery in a containerized setting. Otherwise differences between inoculants and their relative controls were limited, perhaps due to competition from the native soil microbial community, thus inoculation of field plots is not recommended for wheat.