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Earth Additives
Giving Soil What it Needs to Give Back Much


In areas where the soil has been degraded by site preparation, tillage and other activities where topsoil is removed, mycorrhizal fungi, which attach to feeding roots of some seed plants (inset) and expand their root mass so nutrient and water uptake are improved, can be reduced or eliminated. Adding them back to the soil returns their beneficial functions that also include preventing disease by attacking pathogens entering the root zone.
Photo: JRM Chemical

Soil - that amazing combination of inorganic bits and pieces, decomposing organic materials and living matter that provides for plants' nutritional needs and physically supports their growth - is in a constant state of flux due to the climate, its topographical environment and the impact of humans, who can be soil's greatest benefactor.

Besides refraining from practices that harm soil, we can also do much to enrich it by providing it with a variety of organic and inorganic resources that perform very valuable functions to benefit soil and the plants it sustains.

Managing Soil Moisture
Reducing the amount of water used in landscaping is a very high priority presently, and most solutions center on irrigation equipment. But there are consumable products available to not only better control water movement and retention in soils but help conserve water as well. One class of substances is known as surfacants or wetting agents.

According to James Spindler, CPAg, CCA, CPSS, director of agronomy at Ecologel Solutions, these reduce the surface tension of water so that the molecules can better disperse across and in the surface of a solid.


Hygroscopic humectants manage and conserve water by condensing soil moisture vapor or soil humidity back into liquid droplets of water (the hygroscopic component), and holding the droplets tightly enough so they stay near the root (the humectant component), but not too tightly so that the root can not absorb them.
Photo: Ecologel Solutions

"A wetting agent is a material that allows water to more easily penetrate into soil and/or flow through, or infiltrate, the soil," he states. "These materials are valuable when soils have become hydrophobic and will not wet easily."

They also provide better drainage, assist various pesticides and improve seed germination. Another type of water management technology is super absorbent polymers, which can capture and hold greater amounts of liquid than their size, or mass, would suggest.

"These materials are utilized to absorb large amounts of rainfall or irrigation to be used by the plant at a later date," says Spindler. For example, JRM Chemical manufacturers a polymer product called Soil Moist. The company states that it can reduce "plant waterings by 50%, reduce transplant shock and soil compaction and is effective in the soil for 3-5 years." It is designed to store over 200 times its weight in tap water and then release a "steady supply of water as your plants need it.

Best practices from the manufacturer include installing it into the soil at the root level of the plant - not topdressing with it.

According to Spindler, there is a soil additive that is an even more effective tool in water conservation: hygroscopic humectants. These substances attract the water vapor in the soil that the plant's roots cannot use, and condense it back into a liquid, then hold on to it until the plant needs it.


Super absorbent polymers are designed to store many more times their weight in water (over 200 times according to JRM Chemical, the manufacturer of Soil Most polymers). Installation techniques include placing the polymer crystals in the holes left by an aeration machine or using a machine that will inject them into the soil.
Photo: Ecologel Solutions


Whether organic materials such as straw and bark, or inorganic such as rocks or this glass material from American Specialty Glass, mulch benefits soil by reducing water loss from evaporation and runoff, preventing erosion, and reducing compaction.
Photo: American Specialty Glass

"Hygroscopic humectants effectively minimize the loss of soil water to evaporation by condensing the escaping water vapor back into liquid form for the plant to use," Spindler says. "In fact, these products have been documented to reduce overall water use by as much as 50 percent."

These additives can also be used to optimize seed germination and establishment, allow trees, shrubs and ornaments to establish quickly and survive drought conditions more successfully, and, in combination with wetting agents, relieve localized dry spots.

Nourishing the Soil
The most common additive is fertilizer, and as such, doesn't need much more than a review here. The three main nutrients for plants are nitrogen, phosphorus and potassium, with nitrogen being the most important. Formulations come in single nutrient (straight fertilizer) or multi-nutrient (complex fertilizer) - as exemplified by the typical NPK rating, which is listed by three numbers representing the percentage of the nitrogen, phosphorus and potassium in it.

Humates, formed over years from the decomposition of animal and plant life, are one type of organic fertilizer. They contain many valuable nutrients including fulvic and amino acids, humic, and carbon.

Live Earth Products, which mines humate material that is "completely decomposed, ancient plant life" and then manufactures fertilizers, soil amendments and more, attests that improved availability of applied nutrients, a better balance of nitrogen levels for efficient uptake, water conservation and stronger plant and root growth can result from the application of their humate-based products.

Mycorrhizal fungi are one of the beneficial organisms found in healthy soils. They colonize the roots of plants, becoming extensions of the root systems and thereby expanding the root mass. This improves nutrient and water uptake, reduces plant stress and some diseases. However, the potential for soil to form mycorrhizal fungi is damaged by the everyday practices associated with land development. Reintroducing the fungi back into the soil can make it a much better environment for plant growth.

Nitrogen-fixing bacteria can absorb atmospheric nitrogen from the soil and change it into nitrate or ammonia that plants can use to produce proteins. One type is cyanobacteria, which grow as chains of cells that reduce atmospheric nitrogen to plant-available ammonia, and then release it into the soil chemistry to be absorbed by plants. Agronomic product manufacturer Soil Tech manufactures, Microp, which is based on cyanobacteria as a biofertilizer soil inoculant.


Humates, not be confused with humectants, are prehistoric plant matter that is mined by companies like Live Earth Products, which then incorporates it into various manufactured goods, such as fertilizers and soil amendments. When added to the soil, these humate-based products are credited with enhancing its structure, improving the transformation of nutrients from the soil to the plant, increasing water saturation, and repairing decelerated biological activity.
Photo: Live Earth Products


When hydroseeding, soil additives such as hygroscopic humectants can help optimize germination and establishment by reducing "the drying effects in between irrigation and rainfall events," according to Jim Spindler, CPAg, CCA, CPSS, director of agronomy at Ecologel Solutions.
Photo: Finn Corporation

Amending the Soil
Improving the aeration and water absorption qualities of the soil is the main purpose of soil amendments. Dry peat, though it can contain two percent nitrogen, is generally thought of as the most popular of these additives. Coir, bark and sawdust also fall into this category.

A word of warning, according to Wikipedia, some amendments can actually harm the soil. The website references fresh sawdust, which it claims "can consume soil nutrients as it breaks down, and may lower soil pH." On the other hand, "others may increase the availability of nutrients through... increased growth of microorganisms that in turn increase availability of certain plant nutrients."

Holding the Soil
Mulch on top of the soil not only helps prevent erosion, it also reduces runoff of water, helps maintain soil structure by reducing compaction and keeps the soil warmer. Besides bark chips and shredded wood, organic mulches include leaves, straw and other semi-decomposed materials. Rocks, vermiculite and recycled rubber are examples of inorganic mulches.

Mulch suppliers often offer contractors various services to aid in large jobs. SoCal Mulch in Riverside County, California has a blower truck that can deliver up to 40 cubic yards, and apply that amount in around two hours. Green's Best, in California's Central Valley, provides bulk loading at their facility and will create a custom mix of their various products as requested.

The list of beneficial soil additives does not end here, as there are many other types of nutrients, amendments, inoculants and more to help ensure healthy soil composition.

As seen in LC/DBM magazine, February 2018.

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December 6, 2019, 12:40 pm PDT

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