Solublity of a Fertilizer & Jar Test

When applying fertilizers through the irrigation water, it is essential that you know

some important facts about the fertilizers solubility.


What Does Solubility of a Fertilizer Mean?

Solubility of a fertilizer is the maximal amount of the fertilizer, that can be completely dissolved in a given amount of distilled water at a given temperature.

Manufacturers may provide you with solubility data of their fertilizers upon request. Here is an example of solubility data for Potassium Nitrate (expressed as g/liter):

Temperature (C˚) 5 10 20 25 30 40
Solubility 133 170 209 316 370 458

Different manufacturers may provide slightly different solubility data for the same

fertilizer. This is because they use different additives in their products. There are also some fertilizers that may contain insoluble residues.


Dissolving a Fertilizer

When you dissolve a fertilizer, you should not exceed its solubility. Otherwise, a

precipitate may form and might clog the irrigation system. Moreover, the nutrients you intend to provide through the solution may not be fully available.

For example, according to the data in the table above, the solubility of Potassium Nitrate in 20oC is 209 g/l and the fertilizer contains 38% Potassium. If you attempt to dissolve 300 g/l in the fertilizer stock tank, you will not get 114 g/l of Potassium (38% of 300g), but only 80g. The remaining 34g will precipitate and will not be available.

Mixing Fertilizers Might Decrease Their Solubility

When dissolving together two or more fertilizers that contain a common element (for example Potassium Nitrate together with Potassium Sulphate) the solubility of the fertilizers is decreased. In such case, we cannot refer to the fertilizer solubility data alone. The same happens when the water used for dissolution is highly rich with minerals, e.g. calcium, magnesium or sulphate.

In such cases, additional chemical reactions come into play, and calculations become more complex. Usually, these are not calculated in the field and instead, trial-and-error practices are common.


Fertilizers Compatibility

Some fertilizers should not be mixed together in one stock tank because an insoluble salt may form very quickly. An example for such incompatibility is mixing fertilizers that contain calcium with those that contain phosphate or sulphate.

The Jar Test

We've established that when mixing fertilizers, we should be familiar with the solubility data of the fertilizers we use as well as with chemical reactions that may take place. In order to avoid unwanted precipitates, a common recommendation is to perform a "jar test". In this test, the fertilizers are initially mixed in a jar containing the same water used for irrigation.

Prueba de Jarro

Complete dissolution Precipitate formation

The fertilizers should be added exactly in the same concentration as intended to be used in the stock tanks. If a precipitate forms or if the solution has a "milky" appearance, the test should be repeated with lower concentrations of the fertilizers.

Fertigation fertilizers compatibility


All of these calculation and information are automatically incorporated into the simple fertilizer recipes produced by Smart!

Popular posts from this blog

MaZaYdar ManGOes

Image
Mangifera indica L. Anacardiaceae Common Names: Mango, Mangot, Manga, Mangou. Related species: Bindjai ( Mangifera caesia ), Horse Mango ( M. foetida ), Kuweni mango ( M. odorata ). Distant affinity: Cashew ( Anacardium occidentale ), Gandaria ( Bouea gandaria ), Pistachio ( Pistacia vera ), Marula ( Sclerocarya birrea ), Ambarella ( Spondias cytherea ), Yellow Mombin ( Spondias mombin ), Red Mombin ( Spondias purpurea ), Imbu ( Spondias tuberosa ). Origin: The mango is native to southern Asia, especially Burma and eastern India. It spread early on to Malaya, eastern Asia and eastern Africa. Mangos were introduced to California (Santa Barbara) in 1880. Forms: The mango exists in two races, one from India and the other from the Philippines and Southeast Asia. The Indian race is intolerant of humidity, has flushes of bright red new growth that are subject to mildew, and bears monoembryonic fruit of high color and regular form. The Philippine race tolerates excess moisture, h
Read more

Organic Fertilizers, Fungicides & Nutrients

Image
Organic fertiliser is obtained from various chemicals. It contains range of nutrients at different ratio, making it effective for plants. These are easily absorbed in plant systems. Organic Fertiliser are available as solid spray dried powder or liquid solution. This powder if fully soluble in water and can be dissolved in water to prepare formulation of required concentration HUMIC ACID: Application of humic acids has several benefits and agriculturists all over the world are accepting humic acids as an integral part of their fertilizer program. Biochemical active and plant responsive humic substance are naturally occurring humic acids. They can be applied directly to the plant foliage in liquid form or to the soil in the form of granules alone or as fertilizer mix. Benefits of Proper Application of Humic Acid increase soil fertility, Increase humus contents, Effectively chelates meta
Read more

Information for Proper fertilization

Proper fertilization is critical to the healthy and vigorous growth of a lawn. While general fertility guidelines can aid in maintaining high quality turfgrass, even the best recommendations are of little value if one cannot accurately apply the fertilizer recommended. In order to intelligently purchase and apply turfgrass fertilizers, one must be able to read and understand a fertilizer label. Many different types of fertilizer are available for use on turfgrass. Complete fertilizers contain nitrogen (N), phosphorous (P) and potassium (K) and are widely used for turfgrass fertilization. For certain situations, incomplete fertilizers containing some combination of N, P and K, but not all three elements, may be the best choice. Every fertilizer material, whether complete or incomplete, must carry a label stating the guaranteed analysis of the material. The exact label information may vary from state to state, as no uniform countrywide regulations exist; the manufacturer is, however, usu
Read more