BIONIC Carrots: Biological Interactions of Native and Introduced Consortia in Carrots

Commodities

Practices

Vegetable farm soils are often characterized as having degraded soil structure due to heavy disturbance and excessive applications of compost. These factors can make plants more susceptible to pests and drought, reduce nutrient uptake, and present food safety risks. Farmers are increasingly presented with microbial inoculants to help address these challenges. One in particular is arbuscular mycorrhizal fungi (AMF), a symbiotic microbe that can interact with plant roots to increase access to nutrients and water and increase resilience against pests. However, it is unclear if these microbial amendments are worth the cost, or may even cause additional harm. The microbes in these inoculants face and must overcome competition with native soil microbiomes, which could limit their survival and efficacy. At the same time, they could outcompete native microbes that provide system level benefits. One potential way to help ensure the survival and activity of microbial inoculants while also ensuring the integrity of native microbiomes is to apply inoculants together with a biochar soil amendment. Biochar is an organic matter rich porous substrate formed through pyrolyzing organic matter at high temperatures that can also provide soil health benefits. This project was developed based on direct input from farmers seeking answers about these products and will be carried out in collaboration with them.

This project has two primary objectives:

1. Determine whether the co-application of AMF and biochar increases the root associations with AMF, thereby improving the symbiosis between carrot and AMF.
2. Determine how AMF inoculants and biochar interact to influence the survival and efficacy of AMF inoculants as well as the composition and activity of native soil microbiomes.

To achieve these objectives, on-farm trials will be carried out at five farms in Indiana using four treatments (control, biochar, AMF inoculum, and biochar + AMF inoculum). The effects of these treatments on soil and carrot root microbiomes will be determined.

The success of the project will be evaluated using a short survey of farmers who participate in our trials, the participation of farmers and members of the public in field days that will be held in Indianapolis and Lafayette, and the number of farmers reached through an outreach activity at the Indiana Small Farms Conference.

Overall, this study aims to advance sustainable practices for vegetable farms by regenerating degraded soils, strengthening beneficial plant-microbe interactions, and enhancing the economic returns of agricultural systems.

Learning Outcome 1: Identify key factors influencing the survival and efficacy of a popular microbial inoculant (AMF).

Action Outcome 1: Farmers will be able to apply inoculums with greater success and increase the health, productivity and quality of their crops. If the application of microbes or co-application with biochar does not provide clear benefits, then farmers will save money and time used in applying these amendments.

Learning Outcome 2: To gain knowledge on the effects of a popular microbial inoculant (AMF) and soil amendment (biochar) on native soil microbiomes.

Action Outcome 2: Farmers will know whether the application of microbial inoculants with and without biochar are having a positive or negative effect on the native soil biology. If the amendments are supporting the composition and activity of native microbes with beneficial traits, farmers will be able to confidently spend money on and apply these amendments. If the amendments are negatively affecting the soil, farmers will not have to spend money on these treatments and protect their farms.