Fertilizers are responsible for over half of global food production, but there are areas in world with nutrient deficiency and other areas of nutrient excess.
Managing mineral plant nutrients requires careful application of science and skill to meet production, environmental, and social goals.
Saturday, November 16, 2013
Potassium nitrate: a versatile soluble fertilizer
nitrate (KNO3) is a soluble source of two major essential plant
nutrients. It is commonly used as a fertilizer for high-value crops that
benefit from nitrate (NO3-)
nutrition and a source of potassium (K+) free of chloride (Cl-).
Prilled potassium nitrate
Potassium nitrate fertilizer
(sometimes referred to as nitrate of potash or NOP) is typically made by
reacting potassium chloride (KCl) with a nitrate source. Depending on the
objectives and available resources, the nitrate may come from sodium nitrate, nitric
acid, or ammonium nitrate. The resulting KNO3is identical regardless of the manufacturing process.
Potassium nitrate is commonly sold as a water-soluble, crystalline material
primarily intended for dissolving and application with water or in a prilled
form for soil application. Traditionally, this compound is known as saltpeter.
Chemical formula: KNO3
N content: 13%
K2O content: 44 to 46%
Water solubility (20°C): 316 g/L
Solution pH: 7 to 10
Potassium nitrate granules for dissolving
use of KNO3 is especially desirable in conditions where a highly
soluble, chloride-free nutrient source is needed. All of the N is immediately
available for plant uptake as nitrate, requiring no additional microbial action
and transformation in the soil. Growers of high value vegetable and orchard
crops sometime prefer to use a nitrate-based source of nutrition in an effort
to boost yield and quality. Potassium nitrate contains a relatively high
proportion of K, with a N to K ratio of approximately 1:3. Many crops have high
K demands and can remove as much or more K than N at harvest.
of KNO3 to the soil are made before the growing season or as a
supplement during the growing season. A diluted solution is sometimes sprayed
on plant foliage to stimulate physiological processes or to overcome nutrient
deficiencies. Foliar application of K during fruit development can be advantageous
for some crops, since this growth stage often coincides with high K demands
during the time of declining root activity and nutrient uptake. It is also
commonly used for greenhouse plant production and hydroponic culture.
N and K are required by plants to support harvest quality, protein formation,
disease resistance, and water use efficiency. Therefore, KNO3 is
often applied to soil or through the irrigation system during the growing
season to support healthy growth.
Potassium nitrate prills are white
nitrate accounts for only a small portion of the global K fertilizer market. It
is primarily used where its unique composition and properties are able to
provide specific benefits to growers. It is easy to handle and apply, and is
compatible with many other fertilizers. This includes usage for many high-value
specialty crops, as well as grain and fiber crops.
Water solubility of common potassium fertilizers
relatively high solubility of KNO3 under warm conditions allows for a more
concentrated solution than for other common K fertilizers. Careful water
management is needed to keep the nitrate from moving below the root zone.
Non Agricultural Uses
nitrate has long been used for fireworks and gunpowder. It is now more commonly
used in food to maintain the quality of meat and cheese. Specialty toothpastes
often contain KNO3 to alleviate tooth sensitivity. A mixture of KNO3 and sodium
nitrate (NaNO3) is used for storing heat in solar energy installations.