Saline soil is a problem that isn’t new, but is increasing exponentially with poor land management practices and the ongoing effects of climate change. Fortunately, there are a number of strategies you can use to keep producing on your land or in your garden even when there’s too much salt in the soil. Read on to learn about plants that grow in salty soil and how to make the best of coastal growing.
Why is Saline Soil on the Rise?
Saline soil is not a new phenomenon — in fact, salty soils coupled with a lack of rainfall is thought to be the very problem that brought down the Mesopotamian civilization some 4,300 years ago. As growers irrigate with brackish groundwater (as they have for centuries), some of the water is absorbed and the rest is lost through the process of evapotranspiration, causing a buildup of sodium chloride and the gradual salination of the soil.
Compounding the problem in the twenty-first century are rising sea levels due to the effects of climate change. This higher water table increases seepage of the seawater up through the soil in coastal areas and results in salt levels so high that once arable land can be rendered useless for growing.
What is Being Done to Prepare for Increasingly Salty Soils?
Knowing that saline soil is on the rise, gardeners and agriculturalists alike are on the hunt for wild varieties of common crops (such as grapes) that can already tolerate salty soil. Through a process of selective breeding and testing, the hope is that these wild varieties will be crossed with commercial varieties to create cultivars that are more resistant to salt.
The downside to waiting on varieties of plants that grow in salty soil is that a new cultivar could take up to 20 years to produce. In the meantime, other strategies for coping with too much salt in the soil are needed to keep your garden productive.
A fascinating project by the Salt Farm Foundation is working to find cost-effective and localized solutions in areas of the developing world where soil salinity is already affecting farmers’ livelihoods. The research-based strategies employed in this project — known as The Salt Solution — can provide some practical guidance for gardeners and growers in the developed world as well.
The Four Pillars of Saline Agriculture
According to the Salt Farm Foundation, the first step in dealing with saline soil is to test your soil and test it regularly. Knowing how much sodium is present and which nutrients are lacking will enable you to prepare a localized, cost-effective strategy that includes the measures that are needed and avoids those that aren’t.
Once you know exactly what is happening in the soil (including soil type and composition, mineral levels, and microbial activity), you can plan your garden following the four pillars of saline agriculture:
Crop and Cultivar Choice
As you’ve probably realized through trial and error, the soil itself must determine the crops that you grow. When you’re dealing with especially saline soil, veer away from the more salt-sensitive crops such as grapes and almonds and plant more salt-resistant crops like pistachio and alfalfa. Within each species of crop (including vegetables), you can generally find varieties of the plants that grow well in salty soil.
- Cover Crops
For seasonal gardeners with too much salt in their soil, using a nitrogen-rich cover crop in the winter season can help you to maintain a healthy soil structure and safeguard the concentration of nutrients in the topsoil. Research carried out in the Central Valley of California over a three-year period supports the use of the following cover crops on saline soil:
- Brassica species
- Annual grasses (barley, rye, triticale, and wheat)
- Leguminous spp. with the best being:
- Lana and Namoi woolypod vetch
- Purple vetch
- Berseem clover
- Many of the annual medic species
To lower the concentration of salt in the soil, some growers and gardeners have switched to freshwater irrigation rather than brackish water from aquifers and lakes. While this can help reduce your contribution to soil salinity, it can also lead to the scarcity of fresh drinking water for others in the area.
Another way to prevent salt from building up from brackish groundwater is filtering your irrigation water. However, if this isn’t an option due to finances, consider the following irrigation advice:
- Irrigate regularly and keep moisture levels constant. This helps to prevent a buildup of sodium around the roots of your plants.
- Plant over the cool and/or rainy season to minimize evaporation and maximize freshwater irrigation from the rain.
Unfortunately, saline soil can rob your plants of nutrients as well as drying them out, so it’s important to fertilize regularly and carefully. Growing plants successfully in soil that has too much salt requires excellent drainage and soil aeration, and the best way to do this while adding in nutrients is to apply a generous amount of organic matter in the form of regular compost and manure. Regular testing will tell you which nutrients you need to add to the soil, and these results provide the best guide as far as which specific fertilizers to use and how often to apply them.
Fortunately, living in a seaside climate gives you the best chance of doing well with saline gardening techniques because the sandy or sandy loam soil provides the ideal amount of drainage. As well as adding plenty of organic matter to your garden, adding some gypsum to the mix could prove to be the final step that turns your saline soil back into a productive garden.
Adapt to Climate Change with Fruit Growers Supply
With over 100 years in the trade, Fruit Growers Supply is ready to help you adapt to the challenges of climate change today and into the future. Working primarily with growers in the state of California, we offer free consultations and testing programs to help you work out if there’s too much salt in your soil. We can then work with you to develop the irrigation and soil improvement strategies that will help your saline soil bear fruit (or vegetables, or herbs, or nuts…). Contact our team to speak with a representative today!