Fruits of the earth Tessenderlo

FRUITS OF THE EARTH-

GIVING NATURE A HELPING HAND TO FEED FUTURE GENERATIONS.

Tessenderlo Group is an international chemicals company employing more than 7000 people in over 22 countries worldwide. The group’s Inorganic Chemicals division is a major manufacturer of potassium sulphate fertiliser and has an annual production capacity of 750,000 tonnes of sulphate of potash (SOP). Joseph Altham interviewed Dr Nicolas White, the group’s Marketing Director for Fertilisers, to find out why Tessenderlo believes there are new areas of opportunity for its water-soluble SOP products.

IN agriculture, potassium and sulphur are essential nutrients for promoting plant growth. Tessenderlo is one of the world’s most important producers of potassium sulphate fertiliser, commonly known as sulphate of potash (SOP). Its plant at Ham in Belgium has an annual production capacity of 650,000 tonnes. The factory has been making SOP since 1926, employing the Mannheim process. This process involves a chemical reaction at a high temperature between potassium chloride and sulphuric acid, and the plant at Ham is the largest in the world to use this process. The Mannheim furnaces at Ham are particularly well adapted to producing high quality water-soluble SOP.

Across the border, Tessenderlo also manufactures SOP at its French site in Loos, which has an annual production capacity of 100,000 tonnes. The key advantages of SOP as a fertiliser are that it is virtually chloride-free and has a very low salinity index. Certain crops, like strawberries, lettuce and tobacco, have a poor chloride tolerance, meaning that too much chloride in the soil will have a bad effect on their quality. For crops like these, SOP is a much gentler source of potassium than alternatives such as muriate of potash (MOP).

Salinity is a particularly serious issue in the semi-arid climates where there is not enough rainfall to wash the salt away. Here, the wrong type of fertiliser can ruin the soil, as Dr White explained. “If chloride and salt accumulate, this can poison the soil. In one case in Jordan, repeated use of potassium chloride as a fertiliser for potatoes eventually turned the soil white. In soils at risk from salinity, sulphate of potash is the best product to use because among the main potash fertilisers it is the one with by far the lowest salt index.”

A global business

Tessenderlo offers three different types of SOP. The company’s standard powder SOP is widely sold to manufacturers as a raw material for making compound fertilisers. The group also produces SOP in granular form branded as GranuPotasse®. Granu-

Potasse is intended for blending with other fertilisers such as ammonium nitrate or urea. “There is a difference between a compound fertiliser and a blend. With a compound, the nutrients are mixed together in each individual granule, whereas the granules in a blend remain physically distinct particles.”

SoluPotasse®, the third kind of SOP Tessenderlo produces, was specifically developed for use in drip irrigation systems. The market for SOP is global and the output of the Ham factory is sent to countries as far away as Africa and South America. With its own inland harbour, the factory at Ham is in a unique position in terms of logistics. Fertiliser is loaded onto barges at Ham and then sent along the canal to Antwerp for transfer to sea ships. “We also load coasters directly at Ham for shorter voyages to destinations such as the UK and France.”

Soluble SOP for fertigation

SoluPotasse, the company’s soluble SOP, is intended for use in fertigation. “As the word implies, fertigation is a hybrid of fertilisation and irrigation,” explained Dr White. “The irrigation water is delivered as a droplet right into the root zone. This is an efficient way of delivering water and fertiliser, especially in hot climates, and can cut back water usage by as much as 40 per cent. The biggest market for our soluble SOP is Spain, where it helps with growing crops like cucumbers. Other important markets for SoluPotasse include Egypt and Morocco.” SoluPotasse is already the top soluble potash brand, achieving annual sales of more than 100,000 tonnes in over 80 countries worldwide.

Foliar applications

Recently, Tessenderlo has begun to investigate new applications for water-soluble SOP fertiliser. “The main market for SOP has always been fruit and vegetables, although these only account for around 20 per cent of the global crop area. So we asked ourselves whether our product could bring benefits to broad acre crops like cereals, cotton and rice. We ran studies to investigate whether there were any benefits in a foliar application of SOP as a complementary treatment – in spraying potassium sulphate on top of the crop at a key point in its growth.

“In the past, a foliar spray tended to be used only when there were symptoms of potash deficiency. But with crops like wheat, soya, sugar beet and potatoes, we found that a foliar application of SOP can improve yields by between 0.2 and 0.6 tonnes per hectare. One technique that works well in many cases is when about 90 per cent of the potash is applied onto the soil, with the other 10 per cent applied as a foliar spray of SOP. You could say that foliar application of SOP is a bit like an energy drink for a tennis player in the middle of a match. With promising potential for foliar applications of SOP in broad acre crops the group is in the process of developing a brand new grade of SOP with properties specifically tailored to foliar application. We hope to launch the new product, K-LEAFTM, this spring.” n