Inspirational ideas: growing salt-tolerant plants to keep salt levels low in greenhouse soil
In organic greenhouses, where crops are grown directly in the soil, the use of fertilisers and irrigation can cause salts to accumulate over the years. A German Operational Group is testing whether growing salt-tolerant crops, which are adapted to higher salinity, can help reduce salt levels in greenhouse soils.
Some vegetables, such as salad greens, parsley and beans are especially sensitive to salinity, which can lead to yield losses. Operational Group coordinator Stephan Jung explains the issues for German growers: “In some Spanish greenhouses, a large amount of water is applied to the bare soil during a winter break, to wash out excess salts from the sandy soils. This leaching technique is more difficult for German clay soils. Most of our greenhouses also do not have drainage systems that could get rid of the excess water. Leaching will also wash out necessary nutrients, which can cause ground water contamination. And even if leaching were applied, it would take weeks for the soils to dry in our climate. Every week with no production means heavy losses for our farmers.”
Some salt-tolerant crops can store salt in their biomass and actively help reduce soil salinity. The Operational Group has been testing the most promising plants in close cooperation with two organic farmers.