Reduced Plant Growth: For agricultural (or any plant) production, salts are necessary in the form of plant nutrients, but become toxic in excessive quantities. Salts such as calcium (Ca), magnesium (Mg), and sulfur (S) are necessary for plant growth, but saltwater intrusion (SWI) can raise these levels higher than (upland) plants are adapted to. These excess salt reduce the ability of plants to absorb water, causing dehydration (see bottom of the page). These salts may also compete for uptake into the plant, altering nutrient balances. A well known example is how excess potassium (K) can reduce Mg uptake into grasses. Of particular concern is sodium (Na), which can become excessively high following flooding events. Normal Na levels in soil can be 5-40 ppm, but have been observed at 1000 ppm following saltwater intrusion, leading to potential toxicity. Chloride (Cl) is another plant nutrient that can reach excessive levels due to SWI.
These corn plants along the edge of a tidally influenced ditch didn’t germinate or grow in some parts of the field, but are also suffering from excessive dry conditions. Droughts will be worse with excess salts in the soils, which further reduces the ability to obtain water from the soil.
Soil quality can also be reduced with excessive salts, particularly Na, which may cause crusting of the surface, reducing the ability of water to infiltration into the soil. This crusting may also limit germinating seeds pushing through the soil surface.
Agriculture Factsheets
Salt Measurements and Soil Classifications
Effects on Crops of the Delmarva
BOOK CHAPTER: An Introduction to Coastal Flooding Impact on Salinity and Sodicity in Agricultural Fields: https://acsess.onlinelibrary.wiley.com/doi/abs/10.1002/9780891183976.ch13
For an overview of salts in agriculture, you can watch this webinar from the Mid Atlantic Women in Agriculture series. A pdf copy of the slides is available here: Soils and Salts: From Fertilizer to Tidewater.
