Elemental K is not found in nature because of its chemical reactivity. Potash deposits occur as beds of solid salts beneath the earth's surface and brines in dying lakes and seas.
Potassium is mined from a number of minerals. Sylvinite, sylvite and langbeinite are the most important.
- Sylvinite is composed primarily of potassium chloride (KCl) and sodium chloride (NaCl)-containing 20 to 30 percent K20.
- Sylvite is composed mainly of KCI, containing about 63 percent K20-
Langbeinite is composed largely of potassium sulphate (K2SO4) and magnesium sulphate (MgSO4)- containing about 23 percent K2O. (Brines containing K are about two-thirds water and contain about three percent K20)
Potassium chloride- Potassium Chloride, or muriate of potash, accounts for more than 90 percent of the K sold in the U.S. and Canada. It is water soluble and contains 60 to 62 percent K20- Most North American KCI is produced from sylvinite, but some comes from brines. The raw, impure ore is refined to fertilizer by crystallization or flotation processes. Most agricultural KCI is produced by the flotation process.
Fertilizer grade KCI is available in five particle sizes: (1) white soluble, (2) special standard, (3) standard, (4) coarse and (5) granular. Granular is very suited to bulk blending. The white soluble grade is ideal for clear liquids.
Potassium sulphate (K2SO4)- Also called sulphate of potash (SOP), contains about 50 percent K2O and 18 percent sulphur (S). Because its chloride (Cl) content is below 2.5 percent, it is used for Cl-sensitive crops such as tree fruits and tobacco, and to supply S. It accounts for about six percent of total agricultural K sales. Potassium sulphate can be used where Cl buildup becomes a problem.
Sulphate of potash-magnesia (K2SO4-2MgSO4)- It is also called potassium-magnesium sulphate, "Sul-PoMag" and "K-Mag.". It contains about 22 percent K20, 11 percent magnesium (Mg) and 22 percent S. It occurs in nature as the mineral, langbeinite, which is refined to the commercial fertilizer product. It is a good source of water-soluble K and Mg, and is very important where Mg and/or S is deficient.
Potassium nitrate (KNO3)- Potassium nitrate contains little or no Cl or S. It contains about 44 percent K20 and 13 percent N.
Composition of common potassium fertilizer sources:
|Material||K2O - %||Mg - %||S - %||N - %||Cl - %|
Cotton and corn acreage in Mississippi are more than 30% below March projections, while growers of soybeans and peanuts planted much more than initially forecasted.
STARKVILLE, Miss. -- Row crop growers in Mississippi used a relatively dry May to make up for planting time lost earlier in the spring due to wet weather and soggy fields.
As of May 24, planting progress for the state’s four major row crops was slightly behind their five-year averages but ahead of where it was at that time in 2019.
The Mississippi State University Extension Service has a new cotton specialist.
Brian Pieralisi was appointed to that role on April 1. He replaced Darrin Dodds, who took the helm of the university’s Department of Plant and Soil Sciences.
STARKVILLE, Miss. -- Weather always plays a role in the spring planting decisions of Mississippi row-crop producers, but the market impact of the ongoing COVID-19 pandemic is another variable they will have to consider in 2020.
STONEVILLE, Miss. -- Pathologists with Mississippi State University will be monitoring a relatively new plant disease in state cotton fields once the growing season is in full swing.
Cotton leafroll dwarf virus, or CLRDV, was first reported in Alabama in 2017. It is closely related to a cotton virus known to occur in South America. Historically, that virus has caused up to 80 percent yield losses in Brazilian cotton fields.