Soil Science from the International Space Station Comes Down to Earth – In your Garden!
By George Giltner, Adv. Master Gardener, MS Biology
NASA has been developing artificial soils for several decades for use on long duration space flights. These trials have proved that numerous crop species have growth and development similar to plants grown in ground controls.
The advantages of the “Zeoponic Soil Systems” is that only water is needed for activation, and yields are substantially higher than those obtained from the field. The objective is to have a soil substrate for plant growth that can be used in a regenerative life-support system ( a sealed sustainable living space). Data from the Lada greenhouse in the space station has helped advance Earth-based greenhouses and controlled environment Ag systems. This information is also used by researchers and farmers to produce better, healthier crops in small spaces with optimum amounts of water and nutrients.
Commercial products have been on the market for some time. Examples are “Zeo-Pro” which is used as a slow release fertilizer on golf courses. Another product “Miracle Mountain Zeolite” sells zeolite as a garden amendment. For gardening purposes, be sure the zeolite is without a sodium load, examine the heavy metal report, and assure the product is oriented for Ag purposes. Many other products and expanded use of zeolites are expected as advantages are learned. It is definitely a 21st century product. Applications include odor control products (Horse Stall Refresher), Fish hatchery water treatment, a Portland Cement substitute, Kitty Litter, and higher yields in crops and pastures.
What are the benefits of using zeolite in horticulture applications? 1) The CEC (cation exchange capacity – value of available nutrients) is increased. 2) Soil porosity and water holding properties are improved which results in decreases in water run-off and ponding 3) Zeolite increases nitrogen retention by reducing ammonia volatilization, therefore reducing nitrogen pollution. 4) It improves the fertilizer efficiency by capturing nitrogen, phosphorus, potassium, calcium, magnesium and other trace nutrients for utilization by plants. 5) Zeolite can be used as an inorganic substitute for peat moss in mixes. 6) It helps to open compacted soils. 7) biological activity is increased by supporting nitrifying soil bacteria.
A most important use of zeolite is its role in developing controllable and renewable fertilization plans to provide plant growth nutrients. It can be used to mitigate the adverse effects water contamination due to highly soluble and concentrated fertilizers.
Zeolite is a crystalline, porous alumino-silicate with a unique interconnecting, honeycomb lattice structure. This structure of channels of negatively charged alumina, with neutral silica tetrahedral building blocks, can effectively capture positively charged nutrient ions. Because of zeolite’s molecular composition, it has incredible absorbent and adsorbent properties.
In nature, zeolites are naturally formed microporous, alumino-silicates that are found where volcanic rocks and ash layers react with alkaline groundwater. The mineral is also known as clinoptilolite. Check bags of “Kitty Litter” and “Horse Stall Refresher” for clinoptilolite as the effective ingredient. Obnoxious odors and gasses are trapped in the mineral honeycomb structure of these commercial products like fertilizer nutrients are captured in soil-use zeolites.
Most of our local acidic soils are classified as Ultisols composed of kaolinite which has a very low ability (low CEC number) to retain plant nutrients. Therefore most of the commercial fertilizer is lost through leaching with rains and irrigation water. Typically the top 3 to 6” of topsoil contains nearly all of the nutrient value. Additional nutrient depletion occurs when crops are harvested, and when the soil is left barren, and oxidized by tillage. However this soil can be frequently amended with organic matter and humus to increase the pH to a more neutral value, and to increase the CEC to a higher fertility value. This usually requires much labor and effort.
A better system may be to utilize zeolites, organic matter, and inorganic minerals. This approach uses the advantages of each. The zeolite adds a long term substrate to improve the CEC, porosity, nutrient and water retention, and microbial life. The organic matter with cellulose gives life to the soil, water retention, porosity, structure and acts as a slow release fertilizer upon decomposition. Inorganic minerals can be added to supplement deficiencies as indicated by testing or visual symptoms. The overall effect is that leachate pollution is minimized, and fertilization, water, and labor cost are also reduced, while yields are high.
Researchers from the University of Cambridge (Aug 2013, Peter Leggo) has shown that even marginal land like deserts can grow fruits and vegetables using a zeolite mix with chicken manure. Control experiments have shown that dew water can be held on zeolite until the hottest part of the day, which increases overall soil moisture content for plant growth. Dr. Peter Leggo of the Department of Earth Sciences says, “Previously, you’d douse crops with chemicals, and it caused a huge reduction in soil microbial diversity. The material we’ve developed takes less energy to produce, improves soil structure, and enables you to grow crops on almost any type of soil”. Plans are to commercialize the product for world markets.
You may wish to experiment in your own gardens with zeolite soil conditioners and fertilizers. Let us know about your experiences and procedures to share with others in the 21st century.