 |
ProCrop |
Forms of Sulfur Fertilizer
Ammonium Sulfate
Ammonium sulfate (21-0-0-24S) is used to correct or prevent a sulfur deficiency. In the soil, this material's ammonium ions are converted to nitrate by soil bacteria.
Elemental sulfur (0-0-0-90S)
Elemental sulfur is a convenient form of sulfur that can be broadcast of band applied to a number of crops. To be available to plants, elemental sulfur must break down into small particles through purely physical processes, then be transformed to sulfate ions through the activity of soil bacteria (Thiobacillus and others). Break down into small particles can more quickly be accomplished through mixing of the sulfur with bentonite clay in the formulating process. In water a bentonite-sulfur particle swells, breaking up the particle into very fine particles. Once broken into small particles, the increased surface area allows soil bacteria to transform the sulfur to sulfate more quickly. However, even in the presence of small particles, transformation of sulfur to sulfate is a slow process often taking months. Therefore, for most crops in the initial sulfur fertilization year, a sulfate fertilizer like ammonium sulfate is recommended and elemental sulfur is not.
Calcium Sulfate (Gypsum)
Gypsum (0-0-24) has been widely used for many years as a sulfur- and calcium-bearing material for fertilization and soil reclamation. It is a neutral salt and has no effect on soil acidity in our soils. Gypsum is far less soluble than ammonium sulfate and hard to handle, so its use in North Dakota is limited.
Gypsum is a constituent of normal superphosphate (0-20-0). Therefore, sulfur deficiencies seldom occur on land adequately fertilized with this material. In the manufacture of concentrated superphosphates, however, the gypsum is largely removed and these materials therefore contain little or no sulfur. There has essentially been no normal superphosphate used in North Dakota for many years.
Polysulfides and Thiosulfates
Ammonium polysulfide can be applied directly to the soil, metered into irrigation water, or mixed with anhydrous ammonia or ammonia solutions. Ammonia polysulfide is not, however, completely compatible with liquid fertilizers that are highly acidic or have a high salt concentration.
Ammonium thiosulfate is another sulfur-containing material. It can be applied in irrigation water. It is also compatible with many fertilizers solutions such as aqua ammonia, nitrogen solutions containing ammonium nitrate, urea solutions, and most nitrogen, nitrogen-phosphate, or complete fertilizer solutions, It cannot, however, be mixed with anhydrous ammonia or acid solutions such as phosphoric acid, as these materials will decompose the thiosulfates.
Other Materials
Potassium sulfate, potassium magnesium sulfate and magnesium sulfate are being used to supply potassium and/or magnesium to crops. At the same time, they supply sulfur in the readily available sulfate form.
Although potassium chloride is currently the most commonly used potassium fertilizer, potassium sulfate is used to a large extent on specialty crops such as tobacco and potatoes. Potassium magnesium sulfate (K-Mag) is used to supply the three nutrients.
Back to Sulfur - Fertilizer
Menu
Back to Fertilizer Menu
Back to Main ProCrop Index
