After application to soil, most of the thiosulfate quickly reacts to form tetrathionate, which is subsequently converted to sulfate. Thiosulfate is not generally available for plant uptake until it is converted to sulfate. In warm soils, this process is largely complete within one to two weeks. Thiosulfate is a chemical “reducing agent” and it also produces acidity after oxidation of the S. Due to these properties, thiosulfate molecules have unique effects on soil chemistry and biology. For example, a band application of ATS has been shown to improve the solubility of some micronutrients. Local guidelines should be followed for maximum rates for placement in the seed row. Thiosulfate can slow the rate of urea hydrolysis…the conversion of urea to ammonium (NH4 + )…and reduce loss of ammonia (NH3) as a gas when ATS is mixed with UAN. This inhibiting effect is likely due to the formation and presence of the intermediate tetrathionate, rather than the thiosulfate itself. Nitrification...the conversion of NH4 + to nitrate...is also slowed in the presence of ATS. Although the initial pH of thiosulfate fertilizers is near neutral, thiosulfate oxidizes to form sulfuric acid and the NH4 + in ATS will form nitric acid, thus resulting in slight soil acidification in the application zone. Thiosulfates may be applied through surface and overhead irrigation systems, sprinklers, and drip irrigation. Many of them are used in foliar sprays to provide a rapid source of plant nutrition (not recommended with ATS).

http://potassium.ipni.net/ipniweb/region/potassium.nsf/0/58AFA539CC03133085258178006F5140/$FILE/NSS-08%20Thiosulfate.pdf

Calcium thiosulfate is a source of S and Ca 10 and 6% respectively. Potassium thiosulfate is a source of Potassium and Sulfur. Crops like Brassicas have a high sulfur requirement. In saline soils the use of calcium sulfate is important in substituting calcium for saturated sodium conditions. These materials may have some ability to acidify a alkaline condition which can have value. As a potassium source the most cost effective option is usually potassium chloride. For a source of sulfur and calcium sulfate would be preferred to calcium thiosulfate except where there is need to acidify the soil the thiosulfates might have utility. I believe they are more costly that other materials mentioned. All these materials should be applied based on soil analysis and the indication of deficiencies and their remediation. Besides the soil test the tissue analysis can fine tune the crop needs and responses.

Calcium Thiosulfate is a neutral to basic, chlorine-free, clear solution, containing 6% calcium and 10% thiosulfate sulfur. It is an excellent calcium and sulfate liquid that can be used as “liquid gypsum” in treating calcium and sulfur soil deficiencies. Calcium Thiosulfate may be applied by a fertigation system or sprayer. It may be blended with other fertilizers for soil applications.

The advantage of thiosulfate, in comparison to other sulfur forms, is that the sulfur need for plant growth becomes available over several weeks. When sulfur is applied totally in the sulfate form, some may be lost to leaching; the result of rainfall and/or irrigation water moving this form below the root zone. When elemental sulfur is applied, oxidation to a sulfate form must occur before it becomes available to the plant. Thiosulfate helps supply the plant’s sulfur needs quicker than other sulfur forms.

KTS 0-0-25, 17% Sulfur, Potassium Thiosulfate

KTS 0-0-25 17% S is a neutral to basic, chloride-free, clear liquid solution, containing 25% potash and 17% sulfur. Each gallon contains 3 pounds of potash and 2.1 pounds of sulfur. KTS can be applied by drip, sprinkler or flood irrigation. It may be blended with other fertilizers or applied as a foliar treatment on selected crops. When used as a foliar fertilizer, KTS should first be diluted with water before applying. Blends of KTS should not be acidified below a pH of 6.0.

KTS is compatible with urea and ammonium poly- phosphate solutions in any ratio. When blending with UAN solution, a jar test is recommended before mixing large quantities. Potassium reacts with nitrate to form KNO3 crystals. If this should happen, the addition of water and/or heat should bring it back to a clear solution. 

Calcium thiosulphate is chlorine-free, clear solution, containing 6% calcium and 10% thiosulfate sulfur. It is neural to basic in nature and can be used as “liquid gypsum”. Potassium thiosulphate (KTS) contains 25% potash and 17% sulfur. Application of KTS should be made in the middle third or second half of an irrigation set.

About my experience in advicing fertilizer which contains tiosulphate calsium and tiosulphate potassium, firstly, these fertilizers are considered physiologically acidic; because in these fertilizers there are the presence of the sulphate anion which can react with hydrogens of soil solution to produce the sulfuric acid in soils. So it can not be recommended in intertropical soils, which we know, are already acidic starting their origin (Ferralsols or oxisols). These fertilizers can, however, be used in temperate zone wher the soils are alkaline.

Experience in the educational and research process, as well as teaching graduate students in the field of leadership guidance as well as human development and communication guidance, as well as supervision of postgraduate studies, and in the field of research there are many research in the jurisdiction.

Depending on soil type