How Does Sodium Affect Plants?

Types

• According to the Texas Agricultural Extension Service, basic forms of salts are present in all soils and plants at varying levels. All of these salts have one effect or another on plants, depending on several factors. The types of salts are sodium, calcium, potassium, magnesium, chlorides, nitrates, sulfates, bicarbonates and carbonates. Some of the more harmful salts are sodium and chloride, particularly when their levels are high.

Sources

• According to the Texas Agricultural Extension Service, irrigation water is the major source of soil salinity. Another common source of soil salinity is fertilizer, which is mainly comprised of salts. Of course, the naturally occurring salts in the soil don't usually pose a threat to plant health unless there is a natural imbalance or the soil is poorly draining and salts accumulate.

Effect on Soils

• In some cases, salinity actually improves soil structure by causing soil particles to bind together, thereby increasing aeration and allowing plants to take up more water. This is great news for plants, which need well draining soils to thrive and avoid problems like root rot. High soil salinity, however, pulls moisture from the surrounding soil, making it unavailable to plants' roots. This is often the result of irrigation water that has a high salt content. In that case, no matter how much water is available, the plants will still suffer from drought stress.

Signs of Stress

• Plants that are suffering from high soil salinity will not develop properly, will be much smaller than the same plant planted in low-salinity soil and will easily wilt and die. Plants that are already stressed will succumb to pest and disease far more easily than their healthy plant counterparts. According to SMART! Fertilizer Management, perennials seem to be able to cope with salinity better than annuals.