EJP-Soil First call: SoilsalAdapt Preadapting soil biology for increased tolerance to elevated salinities due to climate change

Saltwater contamination is a major contributor to agricultural soil degradation in arid areas, as well as areas that are threatened by climate-driven sea level rise, where it decreases crop yields. If soils as an ecosystem can ‘learn’ to tolerate saline irrigation through more gradual biological adaptation, this means growers may condition soils to remain fertile despite the use of saline irrigation. Farmers will be able to manage the increasingly pressing issue of saltwater contamination. Little is known about how soil organisms respond to increased salinity. Research show that soil organisms from saline soils are more tolerant to salt than those from non-saline soils. Based on this, this project will test a range of saline concentrations to evaluate how biological adaptation works, measure and predict impacts on various scales. Complementary expertise and resources will identify how key wheat root traits in the root/soil interface can improve soil health. Furthermore, plant-associated microorganisms and their functions stimulate plant growth and increase their resistance to changing soil conditions. Research will focus on the quantity and quality of the microbiota that these functions depend on, which among other things is determined by the composition of the soil.

Saltwater contamination is a major contributor to soil degradation in arid areas. In temperate coastal areas dry periods force freshwater level closer to the saline water. The ground water will become increasingly brackish. Growers are faced with either: 1) irrigating with much more expensive treated tap water; or 2) not irrigating which significantly increases the chance of crop failure. Growers are increasingly forced to use the part-saline ground water for irrigation in summer, but the short- and long-term effects are poorly understood. Soil organisms are key to soil fertility, but very little is known about how they respond to increased salinity. Previous work show that saline irrigation affects soil communities, and that soil organisms from saline soils are more tolerant to salt than those from non-saline soils. We will tests whether Darwinian selection processes can ‘push’ soil biological communities to become increasingly tolerant of saline conditions by adaptation. We will test a range of saline concentrations, measure and predict the various impacts of this approach at three scales. At the micro-scale the NO partner will focus on the effects on the rhizosphere. The UK partner will look at medium-scale pot to whole field-scale changes in total soil biodiversity and function by R&DNA sequencing and compare the fertility of soils of various history of saline concentrations in the UK and Portugal. We will also measure any cost of saline irrigation and adaption and how long any effects last. Lastly, the landscape-scale impacts of increased salinity will be modelled by the PT partner, to predict the European and global extent of the issue, and identify the management practices to counter salinization and conserve the soil functions. If soils can ‘learn’ to tolerate saline irrigation through more gradual biological adaptation, growers may condition soils to remain fertile despite the use of saline irrigation and manage this increasingly pressing issue.