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What problems can irrigation cause when salts build up in soil?
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Agricultural technology
Cotton combine harvesting a cotton field.
When salts build up in soil due to irrigation, it creates significant agricultural and environmental problems. Because all irrigation water contains some level of dissolved salts, these minerals accumulate in the soil as water evaporates or is transpired by plants.12
The primary consequences of this salt accumulation include:
- Plant Dehydration: High salt concentrations in the soil make it difficult for plants to absorb water. Through osmosis, water may actually flow out of plant roots and into the soil, causing dehydration and inhibiting growth.12
- Nutrient Deficiency: Excess salinity can interfere with a plant's ability to take up essential nutrients, such as nitrogen.1
- Soil Structural Damage: When sodium ions accumulate, they can be adsorbed by clay particles. This process, known as cation exchange, can render the soil sticky when wet and hard or cloddy when dry, making it nearly impervious to water and root penetration.2
- Toxicity: In some instances, the dissolved salts themselves can be toxic to plants when absorbed through the roots.2
These conditions lead to the deterioration of soil quality and a significant loss of farmland productivity.12