GYPSUM FOR AGRICULTURE
Gypsum is Nature’s very own plant super food. It increases and maintains plant health by providing them with large amounts of Calcium and Sulphur: two elements essential to plant growth. Gypsum is extracted from our open-air mine in Yzerfontein using recycled water only.
What is gypsum and why use it for agricultural use
Natural gypsum is calcium sulfate dihydrate (CaSO4.2H2O) – soluble in water, which releases calcium (Ca) and sulfur (S), absorbed by the plants and crops as needed. Gypsum is used worldwide for ground control, correction and plant nutrition.
The product breaks up clay soils for water intake en drainage, equally removing oiliness out of sandy soils. The pH is managed by gypsum and the necessary calcium and sulfate is added.
Natural gypsum gets formed over thousands of years, mostly in dips (pans) in the earth (later “enfolded” through soil). These depressions usually contain more than gypsum alone, including nitrate, chloride and many other elements. These other elements are washed out over years and then the sulfate ions, binded with calcium, leaving gypsum last. Because of the conditions of the soil (for eg. temperature, rain season etc.),
Here, the gypsum forms at a reasonably early stage (centuries or a couple of thousand years). The crystals are still fine, but bound together. It is very easily spread, does not get blown away by the wind and can be, with ease, crushed finer to the crystal sizes which suits the user’s needs as well as cost-effectiveness. Furthermore, varied crystal sizes controls the solve rate of the product.
The colour of natural gypsum varies depending on the colour of the soil in which the area of the mine is situated.
Function and advantages in the use of gypsum
Agricultural gypsum (reasonably well soluble, 0.2%), is particularly suitable as a low cost Ca source (calcium) and additional S-nutrition (sulfur). A high quality gypsum contains 22% Ca and 16% S, in the SO4 form.
Advantages of gypsum use include:
- Supplementation of calcium (Ca) for rich fruit quality, root growth, disease resistance, etc.
- Good Ca-ions replace the unwanted Na-ions, therefore saline soils get restored to neutralization close to pH 7.
- Addition of sulfur
- Infiltration improvement
- Removal of any oiliness in sandy soils
Infiltration of water becomes especially improved in soils with high amounts of fine sand, silt and clay. These soils have a tendency of compaction, crusting and poor infiltration of rain and irrigation water. With the administration of gypsum, the chemical charge changes in the soil and the clay particles flocculate and air permeability increases. It improves the accessibility of the calcium and sulfur in the gypsum to the plant root, and then naturally allows access to other elements necessary for healthy crops such as nitrogen, phosphor, calcium and more.
Studies have shown that infiltration-pace between 100 – 200% can improve through the administration of gypsum, up to depths of 1.2m. So then: grain, maize, wheat, canola, potato and other crop yields are increased.
It has been found that an improvement of up to 230% in returns / yields has been observed, especially in brackish clay soils.
The role of gypsum quality (purity). Certain impurities included.
There are a number of determining factors at hand when it comes to the purity of natural gypsum. The environment where the gypsum-pan appears, including rainfall plays an important role. Equally, certain ocean inflows land-in that washed back to the sea years prior, as well as the age of the pan.
The higher the purity of the gypsum, the more effective the product, and therewith are less unwanted impurities embedded, and reversed/turned.
Gypsum that is found in lower quality earth/land/ground can be purified through a washing process.
All of this varies from rainfall to rainfall.
Impurities that can occur:
- Silicon in the form of sand. This does not have any negative effect on plant growth.
- Where, in the past, pans were situated close to the ocean or even part of the ocean-inflows centuries or thousands of years prior, phosphor content can pose a dramatic benefit for plant growth. However, this is rare.
- Salt, or sodium. This has no negative effect on soils, not if the content is higher than the prescribed percentage of 1%, as specified by Dept Agriculture.