Effects of Aerated Compost Tea on Swiss Chard, Kale & Lettuce Production in Virginia

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Commodities

• Vegetables: cabbages, greens (leafy)

Practices

• Crop Production: fertilizers, nutrient management
• Soil Management: composting

Solutions to the problem of high-cost, unsafe and non-sustainable commercial fertilizers will involve finding fertility methodologies that are:

• As effective as their commercial counterparts (if not more so)
• Low-cost - with minimal or preferably a one-time investment that does not have to create a reliance on industrial systems
• Sustainable - solutions that can be used to increase the fertility of soil and crops incrementally over time with repeated usage. A solution that "builds soil" with residual effects that are beneficial and not harmful to the environment.

A possible solution to the problem of commercial fertilizers could be using Aerated Compost Tea (ACT) during the growing phase of crops. 

What is Aerated Compost Tea (ACT)?

Aerated compost tea is the cultivation of the diversity and biomass of beneficial aerobic microorganisms in the soil through the suspension of compost in an aerated water solution which includes trace amounts of bacterial food in the form of molasses and fish emulsion (Morgan, 2017). 

The finished solution, shown to have the highest microbial population on Day 3 of aeration, is applied to the soil where crops are grown on Day 2, before the microbial peak, to promote soil fertility and improve crop growth (Kim et al., 2015).

What are the Benefits of Aerated Compost Tea if Proven a Viable Solution? 

If ACT is proven to be viable, its benefits would be the following:

• Lowered Costs for External Inputs in the Current System of Farming

Current costs for farmer fertilizer inputs have risen dramatically this year. 

"Several phosphate and potash fertilizer products have increased by 15-20 percent since late September, while the cost of anhydrous ammonia, urea, and other nitrogen fertilizer products have increased by approximately 50 percent in the past two months. The rapid increase in fertilizer costs is being driven by high global demand, very tight supplies of many fertilizer ingredients, and by shipping issues at U.S. ports"(Thiesse, 2022).

Unlike expensive chemical fertilizers, ACT requires no huge expense apart from the purchase of the following one-time equipment:

• A 5-gallon bucket 
• A 200-watt pump and hose
• A mesh from which to suspend compost
• vermicomposting worms for the creation of bacterially-rich compost or a plant-based thermophilic compost

Thus ACT is not industry-dependent since the farmer can create compost tea on the farm from his or her production waste.

Neither does ACT require a lot of input in time. The ACT process can take as little as 10 minutes to set up as long as a source of compost is readily available.

In this study, pathogen-free vermicompost and hot/thermophilic compost will serve as the source of compost. This compost is created in situ and does not require external purchase or inputs aside from the optional purchase of red wriggler composting worms (Eisenia foetida).

• Similar or Improved Soil and Crop Fertility

ACT has been used as a crop fertilizer, soil amendment, disease-suppressant, and foliar spray (Shaban & Fazeli-Nasab, 2015), playing a possible three-fold agricultural role in food production and negating the need for additional soil amendment or foliar spray products.

In the soil, it introduces higher concentrations of microbial populations to increase their diversity and number. An increase in beneficial microbial life in the soil correlates with an increase in soil fertility (Ingham, 2005).

This microbial life, in turn, increases water retention and improves soil tilth or structure.

The liquid nature of compost tea allows it to seep into the soil and "harder-to-reach" areas without much effort on the part of the farmer.  

If proven viable, ACT could yield similar or better crop fertility, growth, and yield. This would mean better or comparable results without the detrimental effects of chemicals in our soils and food.  

• Increased Nutrient-Density in Crop Production

If proven viable, another benefit of using ACT in crop production would be an increase in the nutrient density of the crops we grow.

Nutrient density means a higher level of nutrition for the customers and community without the ill effects of residual chemicals in food.

What are the Benefits of Studying ACT's effects on Swiss Chard, Kale, and Lettuce?

Swiss chard, kale (Brassica oleracea var. sabellica), & lettuce (Lactuca sativa) have a longer growing season than just the three summer months of June-August in the temperate climates of Virginia.  

As such, they provide a more extended harvest season and longer-term potential income for the farmer throughout the year. 

Proposed Solution

I propose a study measuring the growth, yield, and nutrient density of Swiss chard, kale (Brassica oleracea var. sabellica), & lettuce (Lactuca sativa) grown with and without ACT to discover whether or not ACT could outperform or match the results found by the use commercial fertilizers.   

The benefits of such a solution would be:

• Lowered Costs for External Inputs in the Current System of Farming
• Similar or Improved Soil and Crop Fertility
• Increased Nutrient Density in Crop Production

Research Question and Objective

In this study, I will measure the effects of weekly Aerated Compost Tea (ACT) soil application on the production yield of Swiss chard, kale (Brassica oleracea var. sabellica), & lettuce (Lactuca sativa)

Research Hypothesis

I hypothesize that a weekly application of ACT to Swiss chard, kale, and lettuce will result in the same or improved yields as those to which commercial fertilizers (Nitrogen, Phosphate, and Potassium) are applied.

A secondary hypothesis is that a weekly application of ACT will result in greater nutrient density in Swiss chard, kale and lettuce compared to those to which commercial fertilizers (NPK) are applied.

Data Collection & Measurements

Measuring Crop Yield in Pounds

Using Single-Factor ANOVA (Analysis of Variance) tests, I will measure yield in terms of harvested crops' weight (in pounds) at the end of 100 days for Swiss chard, 60 days for kale, and 70 days for lettuce.

Measuring Nutrient-Density in Crops

With the help of the Bionutrient Food Association (BFA), I will send samples of Swiss chard, kale, and lettuce to the BFA labs for nutrient-dense analysis within a day after harvest.  

Bionutrient Food Association has the largest nutrition database in crops of its kind.

How Crop Testing Works

Growing partners submit food and soil samples to the Bionutrient Institute Lab and share information about how those crops were managed using the BI SurveyStack App. This app walks the user through detailed instructions on collecting food and soil samples and how to package samples for shipping. After the lab receives and processes samples, they return a detailed report on crop and soil nutrition, comparing it against a spectrum of crops in its database.

Location and Choice and Map Plotting

The location I have chosen is the space below to be used for (3) three 12 x 4 beds in our production garden on our farm, Bethany Farms, 41558 Stumptown Rd., Leesburg, VA 20176.

Here is how I plan to use the beds in the experiment:

• Beds 1, 2, and 3 will contain randomly arranged treatments with plantings of Swiss chard, lettuce, and kale. Each crop is numbered one to twenty.
• Red circles represent treatments with ACT.  
• Black squares represent treatments of the crop with NPK (10-10-10).
• Numbered crops without a red circle or black square represent crops not treated with any fertilization.

Project Implementation

If this grant can be funded, I plan to implement the project on April 1, 2023, and grow Swiss chard, kale, and lettuce, two times per year throughout the 2-year research period.

Brewing the Aerated Compost Tea

Aerated Compost Tea (ACT) will be brewed using the guidelines outlined in this SARE Document, "Aerated Compost Tea: A Field Guide to Production Methods, Formulas, and Application Protocols," keeping in mind the need to create a pathogen-free ACT with every application. This manual emphasizes that compost from which ACT is made cannot contain animal products and must be free of four types of pathogens:

• Salmonella
• E.coli
• Listeria monocytogenes and
• Fecal coliforms

This SARE document on ACT also recommended labs that can test compost for the presence of these pathogens before making compost tea from them.  

As part of this study, a sample of finished vermicompost and thermophilic compost would be sent each season to one of the labs mentioned in the document before brewing ACT. This would ensure the pathogen-free nature of the ACT used in the test.  I also plan to do a direct microscopic count of microbiology in 1-hr old ACT.  

Initial Growing & Testing Phase

Crop Trial 1: Spring 2023 (April 1-July 24) 

• Creation of finished vermicompost and thermophilic compost. If found pathogen-free, ACT will be brewed from an equal mixture of both composts. Previous studies on ACT have shown that diversity in compost types produces more effective compost teas (Kim et al., 2015).
• ACT will be applied to the soil-growing media of cabbage, kale, and lettuce seeds sown on April 1 (See timeline in this document).

Crop Trial 2: Summer 2023 (July 31 - November 8)

Winter 2023-2024 (November 13 - March 1) - Consultation is needed as to whether to do the following during this period:

• Grow a cover crop
• Leave the plots fallow
• Keep growing the same crops under low tunnels
• Keep raising the same crops but with crop rotation under low tunnels

Second Growing & Testing Phase

Crop Trial 3: Spring 2024 (April 1-July 24)

Crop Trial 4: Summer 2024 (July 31 - November 8)

Data Analysis, Study, and Outreach Phase

Winter 2024-2025 (November 13 - March 31)

I plan to present my findings at the VA Biological Conference in January 2025.

Observation and Data Recording 

Before harvest, I plan to note any observations of the above-ground growth of Swiss chard, kale, and lettuce. These observations would include, but are not limited to:

• Checking for the presence of 
  • Weeds
  • Pests
  • Disease
• Measuring the "diameter crown" width of Swiss chard, kale, and lettuce

Records on this Google Sheets document.

Photos in this Google Drive Folder.

Documents in this Google Drive Folder.

Data Analysis

After consultation with a Virginia Tech extension agent about the data, I will report on the viability of ACT as an alternative means of fertilization to commercial fertilizers.

Treatments:  I will conduct this experiment using three treatments:

1. Treatment 1: Control - Untreated raised bed of 20 Swiss chard plants, 20 kale plants, and 20 lettuce plants
2. Treatment 2: NPK-Treated crops - a raised bed of 20 Swiss chard plants, 20 kale plants, and 20 lettuce plants that are treated with Southern Ag NPK (10-10-10) All-Purpose Granular Fertilizer (1 cup per 25-foot row / monthly)
3. Treatment 3: ACT-Treated crops - a raised bed of 20 Swiss chard, 20 kale plants, and 20 lettuce plants treated with ACT every week.

Variable: Crop Yield