Organic Matter and Your Lawns Soil

Published: 12th August 2010
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Of all the components of soil, organic matter is probably the most important and most misunderstood. It serves as a reservoir of nutrients and water in the soil, aids in reducing compaction and surface crusting, and increases water, air and nutrient infiltration into the soil.

What is Organic Matter - Material?

Organic material is composed of two classes - "Green Material" and "Brown Material" "Green Material" consists of lawn clippings, manures, compost, etc. It is high in nitrogen content and low in carbon content. "Brown Material" consists of fallen dead leaves and twigs. It is high in carbon content and low in nitrogen content. "Green Material" is the food supply for the soil microorganisms important to decomposition of organic material and nutrients and micronutrients needed to sustain plants. "Brown Material is the home for these microorganisms.

Organic matter is stable in the soil. It is organic material that has been decomposed until it is resistant to further decomposition. Environmental increases in temperature, oxygen, and moisture conditions will speed up decomposition. As much as 90 percent of organic material disappears quickly because of decomposition (10 pounds of organic material becomes 1 pound of organic matter). It is the stable organic matter that is analyzed in the soil test.

What Are the Benefits of Organic Matter?

Nutrient Supply
Organic matter is a reservoir of nutrients that can be released to the soil. Each percent of organic matter in the soil releases 20 to 30 pounds of nitrogen, 4.5 to 6.6 pounds of P2O5, and 2 to 3 pounds of sulfur per year. The nutrient release occurs predominantly in the spring and summer, so summer lawns benefit more from organic-matter mineralization than winter lawns.

Water-Holding Capacity
Organic matter behaves somewhat like a sponge, with the ability to absorb and hold up to 90 percent of its weight in water. A great advantage of the water-holding capacity of organic matter is that the matter will release most of the water that it absorbs to plants. In contrast, earth holds great quantities of water, but much of it is unavailable to plants.

Soil Structure Aggregation
Organic matter causes soil to clump and form soil aggregates, which improves soil structure. With better soil structure, permeability (infiltration of water through the soil) improves, in turn improving the soil's ability to take up and hold water.

Erosion Prevention
This property of organic matter is not widely known. Data used in the universal soil loss equation indicate that increasing soil organic matter from 1 to 3 percent can reduce erosion 20 to 33 percent because of increased water infiltration and stable soil aggregate formation caused by organic matter.

How Can You Maintain or Improve Soil Organic Matter Levels?

Building soil organic matter is a long-term process but is very beneficial. Here are a few ways to do it.

Use mulching blades on you mowers
Lawn clippings contain all the nutrients and micronutrients that the plant needed to grow. Mulching does not contribute to lawn thatch but does reduce fertilization needs. Lawn clippings "green Organic material" decomposes at a 1:10 ratio into organic matter.

Erosion Reduce
Most soil organic matter is in the topsoil. When soil erodes, organic matter goes with it. Saving soil and soil organic matter go hand in hand.

Soil-Test and Fertilize Properly
You may not have considered this one. Proper fertilization encourages growth of plants, which increases root growth. Increased root growth can help build or maintain soil organic matter, especially if you are not removing much of the top growth (mulching).

Consider the benefits of this valuable resource and how you can manage your operation to build, or at least maintain, the organic matter in your soil.

Humic Acid's Role in Improving Soil Quality and Plant Growth

What is Humus or Humic Acid?

The term "humus" dates back to the time of the Romans, when it was frequently used to designate the soil as a whole. It was later applied to the organic matter of soils and composts, or to different fractions of this organic matter; as well as, to complexes formed from a variety of natural organic substances. Humus compounds are complex natural organic compounds that are formed in soils from plant residues, by a process of "humification". Humus materials are complex aggregate of brown to dark colored amorphous substances, which have originated during the decomposition of plant and animal residues by microorganisms, under aerobic and anaerobic conditions. Chemically, humus consists of certain constituents of the original plant material resistant to further decomposition; of substances undergoing decomposition; of complexes resulting from decomposition, either by processes of hydrolysis or by oxidation and reduction; and of various compounds synthesized by microorganisms.

Why Use Humic Acid?

Today, there is a recognized and increasing use of Humic acids for their beneficial impact on the growth and cultivation of crops (vegetable & non-vegetable), citrus, turf, flowers, and particularly in organically-deficient soils. Humic acid is not a fertilizer as it does not directly provide nutrients to plants, but is a compliment to fertilizer.

Benefits include:
Addition of organic matter to organically-deficient soils
Increase root vitality
Improved nutrient uptake
Increased chlorophyll synthesis
Better seed germination
Increased fertilizer retention
Stimulate beneficial microbial activity

How Does Humic Acid Improve Soil?

When applied to clay soils, humic acid can help break up compacted soils, allowing for enhanced water penetration and better root zone growth and development. When applied to sandy soils, humic acid adds essential organic matter necessary for water retention thus improving root growth and enhancing the sandy soil's ability to retain and not leach out vital plant nutrients.

How Does Humic Acid Improve Plant Growth?

As mentioned above, one way plant growth is improved is through the structural improvement of both clay and sandy soil allowing for better root growth development.

Plant growth is also improved by the ability of the plant to uptake and receives more nutrients. Humic acid is especially beneficial in freeing up nutrients in the soil so that they are made available to the plant as needed. Humic acid is also especially important because of its ability to chelate micronutrients increasing their bio-availability.

How Does Humic Acid Affect Microbial Activity and what is its Role?

The activities of beneficial soil microbes are crucial for the sustainability of any soil and plant growth. Humic acid stimulates microbial activity by providing the indigenous microbes with a carbon source for food, thus encouraging their growth and activity. Soil microbes are responsible for solubilizing vital nutrients such as phosphorus that can then be absorbed by the humic acid and in turn made available to the plant. Additionally, microbes are responsible for the continued development of humus in the soil as it continues to break down not fully decomposed organic matter. This in-situ production of humus continues to naturally add to the humic acid base and its benefits.

Humic Acid's Role in Fertilization

Humic acid is technically not a fertilizer, although in some walks people do consider it that. Humic acid is an effective agent to use as a complement to organic fertilizers. In many instances, regular Humic acid use will reduce the need for fertilization due to the soil's and plant's ability to make better use of it. In some occurrences, fertilization can be eliminated entirely if sufficient organic material is present and the soil can become self-sustaining through microbial processes and humus production.

Steve Stout

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