Can Chlorella algae be used as soil amendment to improve crop production?

Methods

Summary

Chlorella cultures will first be grown in sufficient amounts using a 17-watt lamp and a timer set to 16 hours of light and 8 hours of darkness. Experiments will first be conducted with rye and radishes to determine the ideal concentration of Chlorella to use for the tomato and kale experiments. The three concentrations used will be 0%, 1%, and 5%, based on prior research (Taha and Youssef, 2015)  The tomato experiments will be conducted during summer 2020, and the kale experiments during the fall and winter of 2020-2021. Leaf weights, stem lengths, fruit weights, and germination rates will be measured. Shelf life of the resulting crops will be determined by placing five replicates of each crop under refrigeration and determining the length of time before significant moisture loss (over 20%), mold, or other visible characteristics of rot appear. Sugar content will be compared using the Brix method, which uses specific gravity or density to determine the amount present. All experiments will use five replicates for each treatment or control. Crops will be grown at the University of South Carolina West Quad garden in a space measuring four feet by twenty feet. Although water requirements will differ among crops, for each crop an equivalent amount of water will be administered. Soil ecology will be determined using phospholipid fatty acid (PLFA) tests, which measure differences in biological indicators among microorganisms.

Taha TM and MA Youssef, 2015. https://www.researchgate.net/publication/281035679_Improvement_of_Growth_Parameters_of_Zea_mays_and_Properties_of_Soil_Inoculated_with_Two_Chlorella_Species. 

Challenges

Two different crops are utilized in two different seasons to avoid risk of crop failure, which is a ubiquitous risk in agriculture. Furthermore, according to preliminary soil tests, the soil we have chosen is very rich, enhancing the chances of successful harvests. Multiple concentrations of Chlorella will be utilized in the rye and radish experiment to determine the ideal concentration of Chlorella. 

Pre Analysis Plan

The hypotheses will be that crops treated with Chlorella will have higher germination rates, growth rates, and yields than the control group with no soil amendment. The treated group of either tomatoes or kale will also have better shelf lives and flavor and nutrition. Data will be analyzed using nonparametric methods, as the sample sizes will be small. The data will not follow a normal distribution. The significance level for hypothesis testing will be set at 0.05.