Soil health is the foundation of ecosystem health. How do you know if soil is healthy? The answer is soil testing. There are a variety of tests that can be run on soil samples. Soil tests like those found at your local garden center provide relative values of Nitrogen, Phosphorus and Potassium (N-P-K tests) and help homeowners to grow better grass, vegetables or flowers. Soil samples can also be sent to laboratories for more detailed analyses. Traditional tests do not measure the biological component of soils which is a key indicator of soil health. One test we use in our research is the Haney test which provides both chemical and biological data. The respiration measurement from the tests indicates microbial activity in the soil.
In school, many students learn about the mineral component of soil- namely sand, silt and clay- soil texture that varies by geography. From a soil health perspective, the biological component of soil is very important. The types of fungi and bacteria in soil are key indicators of soil health. Some fungi produce a substance called glomalin which coats soils particles and hold them together- high numbers of these types of fungi make us happy. We test for the presence of these microbes using the PLFA test. PFLA refers to the phospholipid fatty acids which make up cell membranes. Bacterial and fungal groups have different structures of PFLAs and this allows us to detect how many and which types of microorganisms are in the soil.
The table below shows select PLFA results from soil at the start of the Ley rotation study. We will continue to run this test throughout the study and compare the results over time.