Over 1.5 billion hectares of land globally are considered to be too saline for food cultivation. Now Marc van Rijsselberghe has discovered various salt-tolerant vegetables and potatoes, and is helping other farmers around the world to grow them.
What do countries such as Ghana, Pakistan, Bangladesh, and the Netherlands have in common? They all have large areas of saline soil that are no longer suitable for agriculture. At least, that was the general view until recently. According to conventional scientific opinion, no agriculture can take place if the irrigation water has a salinity of more than 1.7 deciSiemens per meter (deciSiemens is a measure of electrical conductivity and brackish water is a good conductor because of its salt content). Now agricultural entrepreneur Marc van Rijsselberghe has discovered that there are several crops that can be grown in saline soil.
Van Rijsselberghe explains: “Some types of lettuce, cabbage, beetroots, onions, carrots, broccoli, potatoes and even strawberries will flourish if they are irrigated with salt water in a specific way – at the roots and not on the foliage. Lettuce can grow at a salinity of 8 deciSiemens per meter and many crops can even handle double that. An additional advantage is that these crops are full of flavor.”
Van Rijsselberghe runs Salt Farm Texel in the Frisian Islands along the north coast of the Netherlands. He is now experimenting with various salt-tolerant crops in countries around the world and he teaches his methods to farmers there. If necessary, he even hands out recipes because, as he says, “in Bangladesh they really have no idea what to do with curly kale”.
“An additional advantage is that these crops are full of flavor”- Marc van Rijsselberghe, agricultural entrepreneur
Regional produce from Texel
You don’t have to look far to find out where Marc got his entrepreneurial spirit – from his mother, Lies van Rijsselberghe, who founded Radio Modern, an electronics chain with around 40 shops in the Netherlands. She also owned a dairy farm on Texel. When it ran into difficulties, Marc stepped in to help.
Marc had completed a course in biodynamic agriculture in the UK and was looking after seals and wild birds on Texel at the time. Now he started creating gourmet dairy products on his mother’s farm, such as sea buckthorn yoghurt and curd cheese. He went on to develop around 200 regional products, from skin creams to Texel camembert.
Seventeen years ago Van Rijsselberghe spotted a market for sea vegetables. He read in an agricultural magazine that 2,000 permits had been granted to harvest glasswort and sea aster. “Each permit was for 2 to 4 kg, so I thought there had to be a market for it,” he says. These crops normally grow in salt marshes or mud flats, but he started cultivating them on land inside the dikes.
Although the glasswort did not do well, the sea aster proved a success, with Marc becoming supplier to Albert Heijn, a Dutch supermarket chain. The experiment lasted until one fateful night when thousands of wigeons (a type of duck) settled on his 4 hectare field and stripped it. He received no compensation because sea aster was not listed in the official catalogue of agricultural plant species. And that was the end of that.
Trial & error
In 2006, the VU university in Amsterdam was looking for an agricultural entrepreneur to grow sea kale. Van Rijsselberghe decided to try his luck with sea vegetables again and later began testing the salt-tolerance of other crops. “The VU was researching which genes in plants were responsible for salt-tolerance. We conducted and still conduct experiments based on trial and error.”
Outcomes can be unexpected, as Marc explains: “We were testing six varieties of potato. Each variety was given its own section in the field, bordered by edging plants. An edging plant in this case is a differently colored plant that marks the borders between the sections. Of the six potato varieties tested, not one turned out to be salt-tolerant, but the edging plant – also a potato variety – proved to do very well: it was called the Blue Lady.”
“Only the Blue Lady potatoes proved to do well in saline soil”- Marc van Rijsselberghe, agricultural entrepreneur
Van Rijsselberghe is experimenting with salt-tolerant plants in Bangladesh and Pakistan
Breakthrough for the world’s food problem
Van Rijsselberghe has already tested around 300 species in his open air lab on Texel. He is currently doing research in Pakistan to see whether his four strongest potato varieties are able to withstand not just saline soil, but also the heat and local conditions.
“If that is the case, it will mean a breakthrough for the world’s food problem, as millions of hectares of saline soil will once again be available for agriculture.” According to Van Rijsselberghe, there is more to it than knowledge and the right seed potatoes. “In order to scale up, we need investors and local partners who know the customs and who have the right network. For example, the Rabo Foundation could have an important role to play here.” Van Rijsselberghe is currently in talks with Rabobank about a possible partnership.