Evaluating the effect of seeds coated with commercial, mycorrhizal fungi inoculum on the yields of nantes carrots grown in mineral soil early in the organic transition process

Description

A number of commercial firms extol the benefits of coating seeds with mycorrhizal fungi inoculum. This type of application is believed to positively impact the yields of a variety of crops, including carrots, by enhancing their absorption of water and certain minerals. It may also bring about an increase in hormonal activity and soil aggregation, and enhance resistance to stress. This practice, however, carries a cost. Since agricultural soils naturally contain mycorrhizal populations, it is essential to test whether or not commercial strains compete against native strains to colonize the host plant. In addition, once symbiosis is established, host plants must be tested to determine whether commercial strains perform better than the native strains. According to the manufacturers, the direct presence of the inoculant on coated seed may enable commercial strains to be more effective than native strains in establishing symbiosis.

In addition, mycorrhizal symbiosis is of particular interest in organic farming. The use of mycorrhizal fungal inoculum during the transition period to organic farming could be opportune since some native strains are suppressed in the presence of conventional growing methods and those strains that would normally colonize the host plant, according to organic farming protocols, are not yet well established.

Objective(s)

Overall objective: Test whether or not commercial strains coated on Nantes carrot seeds can compete with native strains in the soil to colonize the host plant and, once symbiosis takes place, whether they succeed in doing a better job than the native strains during the transition to organic farming.

This involves verifying…

• whether mycorrhizal root colonization is as good as or better than colonization in the absence of inoculum,
• whether this colonization can actually be attributed to the commercial strain,
• whether the inoculum alters the levels of nitrogen and phosphorus available in the soil and whether it leads to better plant development,
• whether there is an improvement in the yield and quality of harvested carrots, and
• whether the positive impact of using a commercial inoculant leads to an improvement in production margins.