A New Additive for Poor Soils
By George Giltner, Adv. Master Gardener, M.S. Biology
Simply put, what does it take to have a good garden? University of Cambridge researchers have developed an additive that is capable of growing crops on landfills, deserts, 3rd world agricultural wastelands, and even on gravel. The ingredients are fairly common, therefore anyone should be able to use this additive or the garden principles of the components, to apply to practically any soil. What are these mysterious substances – an organic composted manure and zeolite. The zeolite is a ground, mineral-containing volcanic aluminosilicate rock. Add the correct amount of good water, proper light, an appropriate temperature range, and air for a “successful garden”. It is that simple. Now let’s look at compost and zeolite to understand how they work for plants.
Zeolite is formed from volcanoes when pressurized liquid aluminosilicates and other minerals are suddenly released into our atmosphere. The liquid fizzes out gases, cools, then solidifies like a sponge with a high porosity (up to 45%) and a huge surface area (up to 450 meters/gram). This open framework traps and exchanges valuable plant nutrients (positive ions like calcium, magnesium, ammonium, potassium and trace elements that are essential for plant growth and development). This is what makes it ideal as a soil, compost, and fertilizer additive that captures, and slowly releases critical plant nutrients. Zeolite also physically functions to improve soil structure which allows water and air to flow through with less nutrient leeching and long term soil improvements. The cation exchange capacity (CEC) improvements jump from an approximate 10 (our poor Ultisol soil) to an excellent +120 meq./100g.
Organic plant and animal compost also improves soil structure, but the mechanisms are different from mineral Zeolite. The “Super Glue” of the soil structure, glomalin (a glycoprotein), was discovered by Sara F. Wright, a USDA scientist in 1996 from fungi. Glomalin along with humic acid, are a significant component of compost and soil organic matter. These two complex organic substances bind, store, and slowly release mineral particles which results in improvements in soil quality. Glomalin stores up to 27% of total soil carbon compared to humus’s 8%. Also glomalin makes nitrogen available to soil, provides structure to hold water and for aeration, keeps spaces for root growth, and stabilizes the soil against erosion. In crop soils where fungicides have been applied, there is a reduction in productivity, due to reduction of glomalin production.
The soil life factor of compost really gets the plants growing. The action of microbes is phenomenal as atmospheric nitrogen is changed to useable forms of nitrogen by fungi, bacteria, protozoa and actinomycetes. When these microbes excrete or die, useable minerals and organic compounds are released back into the soil as slow released nutrients. Many new organic fertilizers list the beneficial microbes that inhabit the rhizosphere of roots to form symbiotic relationships (mycorrhizal, antibiotic, enzymatic, etc.) with plants. Larger forms of life, from insects to worms, open tunnels for root growth, gases, and water.
The balance and correct ratio of four chemical elements (calcium, magnesium, potassium, and sodium) influence the physical structure of the soil and the pH also. A correct soil chemistry is necessary to build the house for the biology. For example, if you have a soil or compost that is loaded with sodium from a tap water supply, your plants will not grow to their potential. Excess sodium will cause soil structure to collapse, suck the life out of plants, and will destroy microbial life. Calcium in cell membranes is the doorman that regulates the nutrients that enter the plant. If you have too little calcium in plants, larger amounts of all other nutrients are required for the same yield. And the complexity continues with other minerals. Therefore your best plan is to get a soil test. Get a box from the LSU AgCenter for quick results in several days. Apply minerals as recommended in the reports.
Chances are that most compost additions will buffer the soil, will provide adequate nutrient levels, and will supply trace minerals. Remember that there are accumulator plants that concentrate particular minerals and will affect the pH. What you put into a compost pile is what you get out. Therefore it is a good idea to test compost made from few plant sources before it is added to soil. A wide variety of material usually produces the best mineral-balanced compost.
The most important aspects of gardening are knowledge and experience. Like any art or science, it requires an input of effort, trial and error, and patience. Additions of zeolite and animal compost to your soil will probably produce a decent garden. However, learning the details of gardening will lead to spectacular gardens. Master Gardener classes will begin in January. Call the LSU AgCenter at (337)460-7006 for registration.