The Wonderful World Of Soil Microbes
The next step of the project will be research based and dependent on the students’ ability to find an adequate pioneer species. The decision will need to be made whether that should be a food crop, a fuel crop, or simply biomass tilled back into the soil. This is one of the best chances in the unit to explore different farming techniques and how they are beneficial, detrimental and what would be appropriate. In our project we are planning on having students envision working in a dome. If this was done as planetary terraforming, dust storms would be a large consideration. As an Oklahoma teacher our students are generally taught about the 1930s Oklahoma dust bowl environmental disaster which was caused by many years of draught, high winds and poor farming methods which stripped the soil. The students understand that it was not simply a removal of soil but a loss of light. I will not have my students addressing the issue of 20% less light during a sandstorm however we will consider the fact that Mars only gets 50% of the light that earth does on a good day. Students again will engage with the data to determine growing times as well as light requirements to generate the most biomatter they can.[11]
This moves the process on to fungi and bacteria colonization of the fledgling soil. This opens us to the next set of critical thinking questions that students will grapple with such as, What type of microfauna is best and allows students to determine if their agricultural techniques are effective? We will engage in conversation of the different types of bacteria such as:
- Bacillus: Known as "plant growth-promoting rhizobacteria," species like Bacillus subtilis and Bacillus megaterium aggressively solubilize tightly bound phosphorus and potassium. They also produce enzymes that break down organic matter and help shield roots against pathogenic fungi.
- Rhizobium: These symbiotic nitrogen-fixing bacteria form nodules on the roots of legumes (like beans, peas, and clover). In exchange for plant sugars, they capture atmospheric nitrogen and convert it into a usable nitrate form for the plant to consume.[12]
- Actinomycetes: While technically a type of bacteria, they look and act like fungi. They are famous for their signature "earthy" smell and are critical for decomposing complex, woody organic matter and humus.[13]
- Pseudomonas: These bacteria thrive around the root zone (rhizosphere), protecting plants by consuming resources that harmful bacteria need to survive and producing compounds that restrict pest activity.[14]
- Lactobacillus: Frequently cultured in natural farming practices using fermented starches (such as rice water), these bacteria help break down organic matter, improve soil pH conditions, and suppress the growth of foul-smelling putrefying bacteria.
While Martian regolith has some minerals, it is missing some minerals that are the major components to life. On Earth, soil is a living machine made of rock, water, and organisms. Martian regolith is essentially sterile; it lacks the organic carbon and fixed nitrogen that plants crave. This will introduce students to comparing these mineral components to the nutrients Earth-based plants require like nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), and magnesium (Mg).
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