This project seeks to discover whether mycoremediation strategies can decrease P load to the lake. Specifically this project will analyze whether mycorrhizal inoculated plantings decrease P concentrations in drainage water compared to drainage ways naturally colonized by non-native species.
Objective 1: Decrease the P concentrations in drainage water by greater 50%. We will measure the reduction of sediment-bound and dissolved phosphorus.
Objective 2: Measure the establishment of pollinator, edible, and medicinal plants.
Objective 3: Disseminate our results and information on green infrastructure to the regenerative agriculture and academic communities.
If these strategies succeed, farmers can replicate this model to decrease legacy P runoff without malaffecting the hydrology. Farmers will benefit from these low cost green infrastructure systems, which provide their farms with increased climate change resilience, diversified habitats, greater nutrient retention, and little long term maintenance as well as edible and medicinal products from the required biomass harvest.
The purpose of this grant is to test hypotheses that mycorrhizal vegetation replacing invasive species within drainage and adjacent to agricultural drainage channels can remediate legacy P in drainage discharge (measured as soluble reactive phosphorus, SRP). Preliminary soil samples have been collected to characterize the fertility and P concentrations in soils (measured as modified Morgan extractable P). Site preparation that includes removal of invasive plants, preparation of treatment channels and adjacent riparian areas will begin in February 2020 and will be finished in June 2020. Plants will be inoculated with species specific endo- and ectomycorrhizae in March 2020 for planting in June 2020. After a 2-month acclimatization period, we will begin sampling water in the drainage way and measuring SRP and phosphorus in plant tissue. Water samples will be taken during base flow events and at the end of each large storm event (> 1 inch over 24 hours).
Plant P will be determined by tissue analysis. We will also determine mycorrhizae colonization of restoration plants in July 2020 and 2021.
In addition we will measure plant community and particularly pollinator habitat by enumerating flowering plants (by species) and their flower production and comparing this to a reference chart of pollinator diversity for each species.
Phosphorus pollution from agriculture is one of Lake Champlain’s multiple water quality issues. As a limiting nutrient in freshwater ecosystems, excessive phosphorus,causes algal blooms, including toxic algae that impair tourism through beach closures and limit other water-related activities. According to the EPA’s 2016 Phosphorus Total Maximum Daily Load (TMDL) agriculture accounts for an estimated 41% of base phosphorus loading for the Vermont portion of the Lake. Decades of phosphorus imports as animal feed and fertilizer have caused a build up of excessive P concentrations in the watershed, also known as legacy P (Roy, 2018). Lake Champlain received a D+ in its cleanup report card, stating there is limited data on agricultural practices’ ability to remove phosphorus pollution. (Weber, 2018) This project directly addresses this.
In a climate change adaptation survey (White, 2018), 74% of responding farmers demonstrated awareness of the problem, stating that they build soil health and use cover crops to manage heavy precipitation and flooding on their farms. The respondents emphasize holistic approaches, like regenerative agriculture, agroecology and permaculture (keyline, hugelkultur, berms, swales, and earthworks). This data indicates that farmers are open to alternative practices proposed in this pilot.
Green stormwater infrastructure is now an accepted tool of urban pollution mitigation. This is not yet true for agriculture. In particular, incorporating fungi in mitigation of agricultural non-point pollution is not yet an accepted practice. Cover crops and nutrient recommendations are commonly practiced. However, these BMPs do not mitigate legacy phosphorus that leaves a field through drainage ways. However, arbuscular mycorrhizae increase plant nutrient uptake efficiency (Phillips, 2017; Smith and Read, 2008; Jones, 2009). Innoculations plantings in drainage ways help mitigate legacy phosphorus.
A survey of 21 VT farmers (18 are certified or operationally organic) conducted by MycoEvolve (co-PI Rubin) indicates high farmer interest in mycoremediation. Seventeen of the 21 farmers (81%) are interested in mycoremediation strategies. Six would attend workshops at current pilot demonstration sites, 8 would attend public workshop highlighting research, 12 would consult fact sheets, 9 would take a class geared specifically to farmers, and 10 would access results in peer reviewed journal articles. However, concerns about implementing mycoremediation included effect on climate change resiliency ( 5 respondents), cost (9), long term maintenance (11), potential hydrologic changes (3), displacing space geared towards productivity (6), and lacked knowledge about the topic (4).
At Shelburne farms total phosphorus concentrations in drainage water is 10 to 100 times greater than recommended phosphorus concentrations for that section of the lake (Dana Bishop, unpublished data). This is in- spite of sustainable farm practices. Legacy phosphorus is suspected as a source, but other sources cannot be ruled out. Our project would modify a drainage way with mycorrhizal inoculated vegetated swales.
In addition to farmers, storm-water designers, environmental managers and policy makers have expressed interest in mycoremediation. After introducing MycoEvolve’s EPSCoR BREE research at a MS4 Subcommittee of the Chittenden County meeting, MycoEvolve signed a contract with the Colchester town for a pilot applying similar green infrastructure strategies to a locally impaired waterway.
Due to the habitat present at the site, the objectives changed slightly, removing a percentage claim of SRP reduction and focusing on pollinator habitat measurements :
This project seeks to discover whether mycoremediation strategies can decrease SRP load to the lake. Specifically this project will analyze whether mycorrhizal inoculated native plantings decrease SRP concentrations in drainage water.
Objective 1: Compare the effect on SRP concentrations in agricultural drainage ways with removed invasive plants and native plantings with and without mycorrhizae.
Objective 2: Quantify the increase in pollinator habitat due to the restoration efforts in the agricultural drainage way.
Objective 3: Disseminate results to the agricultural and academic communities.
August/September 2019: Site Analysis: Jess Rubin walked site with UVM Extension consultant, Dana Bishop Farmer, and Water Resource Manager Consultant Lauren, and soil scientist Josef Gorres. Coordinate with Shelburne Farms on the final research and landscape design. Secured project with VYCC and walked site wtih Justin. Output: Drafted design outline and created series of maps: site map, contours, hydrology, installation plan.
October/November 2019: Ground truthed measurement, ground truthed soil morphology through soil pit study, layed out design, took initial water and soil samples in existing drainage way and throughout site. Conducted soil morphology and hydrological analysis. Output: identified SRP and TP hotspot for installation location. Crated an initial site analysis report with recommendations and site limitations.
November/December 2019: Coordinate with Shelburne Farms and VYCC installation details, spring/summer schedule. Began intern search. Began plant palette and mycorrhizae species orders. Located companies to order plants, mycorrhizae and erosion materials from. Output: solid plan for spring summer installation. Planting sketch and initial palette. Rough draft of methodology data tables created.