What can be a consequence of high soil salinity?

High soil salinity can lead to reduced plant growth due to osmotic stress, which is a significant consequence of elevated salt levels in the soil. When soil salinity is high, the osmotic potential of the soil solution increases, making it more difficult for plants to absorb water. As a result, plants may experience dehydration as they lose water to the saline environment, leading to reduced turgor pressure and impaired physiological functions. This osmotic stress can also interfere with the plant's ability to take up essential nutrients, further hindering growth and development.

In contrast to the correct choice, high salinity does not enhance water retention in the soil, as increased salt concentrations often lead to poorer soil structure and drainage. Additionally, it does not improve nutrient uptake by plants; in fact, it can have the opposite effect, making it harder for plants to access nutrients. Finally, high salinity typically reduces biodiversity in the soil ecosystem, since many organisms, including beneficial microbes, are sensitive to saline conditions and may not survive or thrive in such environments.