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Gypsum is everywhere. It is the most common sulfate mineral on earth and of immense commercial value. Gypsum, known technically as Calcium Sulfate, is one of the most useful and widely used minerals of the 20th century. It is used in the building industry, food and beverages, pharmaceuticals, and as a soil additive for the landscape industry, and agriculture. Yet, despite gypsum's widespread use, few people know what it is or where it came from. Gypsum deposits are sediments from ocean brine and ancient inland seas. Time, heat, pressure, moisture, movement and mixing with other elements produces various forms of gypsum.
Mother nature provides two kinds of natural gypsum for agriculture: ANHYDRITE and DIHYDRATE. Chemically, the only difference between anhydrite gypsum and dihydrate gypsum is two molecules of combined crystallized water. Dihydrate(CaSO4+2H2O) contains two molecules of water and anhydrite (CaSO4) contains no water molecules. The absence of water molecules in anhydrite makes it harder "denser" and heavier than dihydrate. The perferred  quality Gypsum, is predominantly anhydrite gypsum.

The value of agricultural gypsum is directly related to its percentage of Calcium Sulfate. It is the anhydrite that accounts for the high calcium sulfate content. Although the value of gypsum as a soil additive has been recognized for decades, each year field tests around the world reveal more and more of the benefits of

Gypsum (Calcium Sulfate - CaSO4) is one of those rare materials that performs in all three categories of soil treatment: an amendment, conditioner, and fertilizer. Gypsum amends soil alkalinity, lowers high pH conditions and raises low pH conditions, and leaches out harmful salts. Gypsum conditions and improves soil structure allowing air and water penetration and root development.
Gypsum nourishes the plant with Calcium & Sulfur                                     

      Gypsum (Calcium Sulfate - CaSO4) is one of those rare materials that performs in all three categories of soil treatment: a soil amendment, conditioner, and fertilizer.    

Soil conditioners, such as gypsum, are seriously undervalued compared to fertilizer usage. Dr. Arthur Wallace (Ph.D. Soil Science and Plant Nutrition) and Dr. Garn Wallace (Ph.D. Bio-Chemistry) of Wallace Laboratories in El Segundo, CA, U.S.A., believes that if soil structure ain't right, then nothing is right.

Gypsum contains both calcium and sulfur.  Calcium as “ engineering superstar will be applied to agricultural crops and landscapes more than any other nutrient.  Sulfur, once considered to be of minor importance, is now regarded as a major, essential nutrient along with nitrogen, potash and phosphorus.

When dissolved in water gypsum becomes calcium ions (Ca2+ and sulfate-sulfur ions (S042). Both of these ions are required nutrients for growing plants. In addition to being a major plant nutrient, calcium plays a vital role in establishing and maintaining good chemical balance in soil, water and plants.     

There is a great deal of confusion concerning the solubility of gypsum. Solubility has emerged as almost the sole criterion for evaluating gypsum. But, as a singular concept, separate from other factors, the importance of solubility is more misunderstanding than reality. As a practical matter, solubility only has meaning in relation to time, particle size and purity. 

Soluble calcium is the calcium found in the water in the soil or by applying gypsum to the soil. Soluble calcium is directly available for uptake by plants growing in the soil. Insoluble calcium is often found in the soil as calcium carbonate (The caliches soils in the Texas Hill Country) and is not ready available to plants. This form of calcium can only be converted to soluble calcium by reaction with acid. 

Lets look at it from the plants point of view. The bottom-line question here is AVAILABILITY. How much calcium sulfate (nutrition) is available to the plant to meet its gypsum requirement when it needs it? As plants grow, they require continuous supply of calcium because calcium becomes fixed and immobile within the plant tissue.   

The same is true with the soil. If it does not get gypsum when it needs it, the soil may compact, prevent water and air penetration, lose its leaching ability and become saturated with salt or other excessive elements harmful to plant growth and health. Then the plant suffers from bad soil conditions. Poor soil structure is a major limiting factor in plant health or crop yield.

Soil management is a continuing and long term process.  There is no sudden cure for ages of soil abuse and mismanagement. The application of gypsum is a not a quick fix alternative with over night results, however in the long term, soil moisture and soil

Benefits of Gypsum

Gypsum Improves Soil Structure - Gypsum provides calcium which is needed to flocculate clays in acid and alkaline soil.

Gypsum Helps Reclaim Sodic Soils - Where the exchangeable sodium percentage (ESP) of sodic soils is too high, it must be decreased for soil improvement and better crop growth. The most economical way is to add gypsum which supplies calcium. The calcium replaces the sodium held on the clay-binding sites. The sodium can then be leached from the soil as sodium sulfate to an  appropriate sink. Without gypsum, the soil would not be leachable.

Gypsum Prevents Crusting of Soil and Aids Seed Emergence - Gypsum can decrease and prevent the crust formation on soil surfaces which result from rain drops or from sprinkler irrigation on unstable soil. It can prevent crusting that results when acid soils are lime& the gypsum is co applied with the lime.

Gypsum Improves Low-Solute Irrigation Water - Gypsum is used to increase the solute concentration of low-solute water used for irrigation. Irrigation water from rivers that no longer have sources of leachable salts either penetrates poorly into soil or causes soil particles to degrade which results in low-water penetration. The problem can be corrected with surface-applied gypsum or application to the irrigation water.

Gypsum Improves Compacted Soil - Gypsum can help break up compacted soil and decrease penetrometer resistance. Combination with organic amendments also helps, especially in preventing return of the compaction.

Gypsum Makes Slightly Wet Soils Easier to Till - Soils that have been treated with gypsum have a wider range of soil moisture levels where it is safe to till without danger of compaction or deflocculation.

Gypsum Stops Water Runoff and Erosion - Gypsum improves water infiltration rates into soils and also the hydraulic conductivity of the soil.

Gypsum Decreases pH of Sodic Soils - Gypsum immediately decreases the pH of sodic soils or near sodic soils from values often over 9 but usually over 8 to values from 7.5 to 7.8. these values are in the range of acceptability for growth of most crop plants.

Gypsum Increases the pH of Acidic Soils - One mechanism in which gypsum can increase soil pH enough in some acid soils to sufficiently decrease the level of soluble aluminum to grow crops satisfactorily is replacement of hydroxyl ions from some clay lattices by sulfate ions.

Gypsum Improves Swelling Clays - Gypsum can decrease the swelling and cracking associated with high levels of exchangeable sodium on the montmorillonite-type clays. As sodium is replaced by calcium on these clays, they swell less and therefore do not easily clog the pore spaces through which air, water and roots move.

Gypsum Prevents Waterlogging of Soil - Gypsum improves the ability of soil to drain and not become waterlogged due to a combination of high sodium, swelling clay, and excess water.    

Gypsum Can Help Remove Excess Boron from Sodic Soil - More boron was leached from sodic soils when gypsum was applied than when the soil was leached without gypsum.

Gypsum Increases the Stability of Soil Organic Matter - Gypsum is a source of calcium which is a major mechanism that binds soil organic matter to clay in soil which gives stability to soil aggregates.

Gypsum Makes Water-Soluble Polymer Soil Conditioners More Effective - Gypsum complements or even magnifies the beneficial effects of water soluble polymers used as amendments to improve soil structure.

Gypsum Makes Excess Magnesium Non-Toxic - In soils having unfavorable calcium magnesium ratios, such as serpentine soils, gypsum can create a more favorable ratio.

Gypsum Corrects Subsoil Acidity - Gypsum can improve some acid soils even beyond what lime can do for them. Surface crusting can be prevented. Gypsum is now being widely used on acid soils.

Gypsum Can Enhance the Values of Liming - Addition to soil together with lime increased crop yields. The combination also decreased leaching losses of potassium and magnesium.

Gypsum Improves Water-Use Efficiency - Gypsum increases water-use efficiency of crops. In areas and times of drought, this is extremely important. Improved water infiltration rates, improved hydraulic conductivity of soil, better water storage in the soil all lead to deeper rooting and better water-use efficiency. From 25 to 100 percent more water is available in gypsum-treated soils than in nontreated soils.

Gypsum Creates Favorable Soil EC - Gypsum, being readily soluble, results in proper buffered solute concentration (EC) in soil to maintain soil in a flocculated state. It is better environmentally and costwise to maintain the needed EC with gypsum than with excess application of fertilizers.

Gypsum Makes it Possible to Efficiently Use Low Quality Irrigation Water - Use of reclaimed municipal waste water is important for conservation of natural resources. Reclaimed water can be satisfactorily used if amendments, such as gypsum and water-soluble polymers, are also used.

Gypsum Decreases Dust Erosion - Use of gypsum can decrease wind and water erosion of soil. Severe dust problems can be decreased, especially when combined with use of water-soluble polymers.

Gypsum Helps Plants Absorb Plant Nutrients - Calcium, which is supplied in gypsum, is essential to the biochemical mechanisms by which most plants nutrients are absorbed by roots. Without adequate calcium, uptake mechanisms would fail. Our Hill Country caliche soils are high in calcium, however it is not in a soluble form for plant uptake.  

Gypsum Decreases Heavy-Metal Toxicity - Calcium also acts as a regulator of the balance of particularly the micronutrients, such as iron, zinc, manganese and copper, in plants. It also regulates non-essential trace elements. Calcium prevents excess uptake of many of them; and once they are in the plant, calcium keeps them from having adverse effects when their levels get high. Calcium in liberal quantities helps to maintain a healthy balance of nutrients and non-nutrients within plants.

Gypsum Increases Value of Organics - Gypsum adds to the value of organic amendments.

Gypsum Improves Fruit Quality and Prevents Some Plant Diseases - Calcium is nearly always only marginally sufficient and often deficient in developing fruits. Good fruit quality requires an adequate amount of calcium. Calcium moves very slowly, if at all, from one plant part to another and fruits at the end of the transport system get too little. Calcium must be constantly available to the roots. In very high pH soils, calcium is not available enough; therefore, gypsum helps. Gypsum is used for peanuts, which develop below ground, to keep them disease free. Gypsum helps prevent blossom-end rot of watermelon and tomatoes and bitter pit in apples. Gypsum is preferred over lime for potatoes grown in acid soils so that scab may be controlled. Root rot of avocado trees cased by Phytophthora is partially corrected by gypsum and organics.

Gypsum is a Source of Sulfur - Gypsum is a source of fertilizer sulfur.

Gypsum Helps Prepare Soil for No-Till Management - A liberal application of gypsum is a good procedure for starting a piece of land into no-till soil management or pasture.

Gypsum Decreases Bulk Density of Soil - Gypsum-treated soil has a lower bulk density compared with untreated soil.

Gypsum Decreases the Toxic Effect of NaCI Salinity - Calcium from gypsum has a physiological role in inhibiting the uptake of sodium by plants.

Gypsum Multiplies the Value of Other Inputs - Gypsum can improve the response to all other inputs including fertilizers.

Gypsum Can Decrease pH of Rhizosphere - Increased calcium uptake by roots when gypsum is applied can decrease the pH of the rhizosphere.

Gypsum Keeps Clay Off Tuber and Root Crops - Gypsum can help keep clay particles from adhering to roots, bulbs and tubers of crops like potato, carrots, garlic and beets.

Gypsum Decreases Loss Of Fertilizer Nitrogen to the Air - Calcium from gypsum can help decrease volatilization loss of ammonium nitrogen from applications of ammonia, ammonium nitrate, urea, ammonium sulfate, or any of the ammonium phosphates.

Gypsum Can be a Source of Oxygen for Plants - The sulfate that is taken up by plants and metabolized releases the associated oxygen which is a source of oxygen to plant roots although a limited source.

Gypsum Helps Earthworms to Flourish - A continuous supply of calcium with organics is essential to earthworms that improve soil aeration, improve soil aggregation and mix the soil.

Gypsum Can Increase Water Retention in Soil - Gypsum when applied to sodic soil decreased levels of exchangeable sodium resulted in a large increase in water retention at a given tension compared with controls. Dry matter and seed yield were increased as a result.

Contact: cell: 830.257.8871
                     Jim Rediker - Nurseryman -  Arborist  - TDA Certified

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