Soil salinization is a serious problem all over the world. The global annual cost of salt-induced land degradation in irrigated areas is about US$ 27.3 billion. Amelioration and utilization of salt-affected lands are of great importance in feeding the world's growing population.

The adverse effects of salt, osmotic pressure inducing physiological drought and specific ion damage on plant early stage growth have been intensively studied. However, nutrient deficiency of saline soils has received much less attention.

In a study published in Land Degradation & Development, Assoc. Prof. ZHANG Hongxiang from Northeast Institute of Geography and Agroecology of the Chinese Academy of Sciences and her collaborators studied the role of nitrogen (N) to emergence and growth of important forages Leymus chinensis (L. chinensis) and Medicago sativa (M. sativa) in saline soils.

Using a 2×2×3×3 (2 forages, 3 salt solutions, 3 nitrogen solutions, 2 sowing conditions) factorial design, the researchers found that nitrogen addition and mixed sowing significantly increased germination rate and seedling height of L. chinensis, but not Medicago sativa.

Besides, they found a new mechanism in the mixed community that M. sativa absorb Na+ and form a ‘micro-bioremediation’ environment around the grass, thus increasing germination and growth of L. chinensis.

Successful establishment is a key determinant for cultivation of plants in degraded saline soils. This study provides important information for grass-legume mixed pasture establishment in degraded saline soils, which helps to achieve the sustainable use and improvement of degraded saline soils.