Salt farming: New practices for a changing climate

“Agriculture plus a few tricks”

With unprecedented heat and drought in Australia and enduring dry weather across much of the northern hemisphere, salt levels in soil are on the rise. To adapt to these changes, researchers are developing best practices for saline agriculture.

A version of this article was previously posted on on March 27, 2018.

After his doctoral research into salt-tolerant ecological fertilizers, ecologist Bas Bruning opted to stay in the field. He finds it rewarding to combine research and practice to help farmers in various countries with saline agriculture. At Salt Farm Texel on the Dutch island of Texel, he researches crops that are suitable for growing under saline conditions. “Saline farming is agriculture plus a few tricks,” he says, with considerable understatement.

Bruning speaks here about the causes and effects of salinization, and the ways salt farming can address changing soil composition globally.

Ecologist Bas Bruning: By 2050, fifty percent of soil is expected to be affected by salt

How is salinization threatening food security?

At the moment, the Food and Agriculture Organization of the United Nations (FAO) estimates that about 33 percent of all irrigated farmland in the world has been affected by salt. This is expected to increase to 50 percent by 2050. Salinization takes place everywhere, especially in dry to moderately dry areas, with Asia, North Africa, the Middle East and Australia particularly affected. In general, as the salinization of soil and water increases, soil productivity and crop yields decrease, until the impact is so strong that the land can no longer be used for food production.

“Climate change is increasing global salinization”

- Bas Bruning, ecologist and agricultural researcher

Why is salinization increasing?

Salinization is partly caused by humans. The process is fed by people using the wrong irrigation methods. Irrigation water is usually slightly saline and when you pour it over crops, the water evaporates quickly, leaving the salt behind. This salt accumulates, eventually causing negative effects.

Climate change is further increasing global salinization. In some areas, that’s due to extreme precipitation causing saline groundwater to rise. In others, extreme drought means more irrigation, ultimately increasing water scarcity. Rising sea levels are also causing salinization.

Bruning leads a saline agriculture workshop for foreign farmers

How can saline agriculture contribute to the solution?

Instead of trying to reduce the salt concentration in the soil, saline agriculture offers ways to use or reuse salt-contaminated soils in farming. It is therefore important to stabilize the salt concentration. This can be done with a good drainage system and smarter irrigation in frequency, quantity and manner – at the root, and not on the leaf. Then you have to choose the right crops and varieties. The salt level of the soil determines the choice of crop or variety.

“The salt level of the soil determines the choice of crop or variety”

- Bas Bruning, ecologist and agricultural researcher

Which crops are suitable for saline agriculture?

In the test beds of Salt Farm Texel, we have been researching the salt tolerance of crops and specific varieties for years. It appears that various varieties of potato, carrot, onion and cabbage thrive on saline soil. Furthermore, factors like tillage and seed treatment play an important role.

How can you give the seeds the best possible start and improve their germination? How can you add extra ingredients to the soil life to stimulate the good bacteria and fungi? We are currently researching all this. Equipped with this knowledge, you can use large areas of salt-contaminated land to grow food.

Where are you currently growing salt-tolerant crops?

We’ve been active for some time in the coastal areas of Bangladesh, growing onions, carrots and all kinds of Brassica such as cauliflower, kohlrabi and broccoli. The first saline harvest has just been gathered there. We have set ourselves the goal of teaching 5,000 farmers the principles of saline agriculture within three years, using a train-the-trainer concept, to make their land productive again. We are on course to achieve that. In Pakistan, we have just completed a potato project. With half of the usual amount of fresh water and in saline areas we achieved a 40 percent higher yield than the national average. We are also active in Europe with the SalFar project. And I have just returned from Egypt, Pakistan and Iran. We are currently inundated with requests.