Soil salinity and pH are two crucial indicators for plant growth and proper crop nutrition. Below, we examine what these two factors mean and which best practices help regulate salinity and pH effectively in agricultural soils.
The problem of salinity throughout the centuries
Irrigation has caused agricultural soil problems since ancient times, as the need for proper drainage was not understood until recently. This often led to reduced soil productivity and contributed to the decline of civilizations based on agriculture. A notable example was the Sumerians of Mesopotamia, who irrigated their land intensively near the Diyala River, leading to soil salinization as early as 2400 BC.
What are salinity and pH, and what causes them?
Salinity
Irrigation water, regardless of its quality, contains dissolved mineral salts, the concentration and composition of which depend on the origin of the water.
For example, water from snowmelt or reservoirs contains fewer salts than groundwater in coastal areas and treated wastewater. Therefore, improper control of the quantity and quality of water entering the soil will result in high salt concentrations (salinity).
Why is salinity measurement important?
Salinity is a fundamental concept for producers, as it affects plant nutrition. Depending on its value, it can reduce or even halt nutrient uptake. This is because it reduces the water potential and, therefore, the availability of water for plants. For this reason, techniques have been developed to measure and quantify salinity, which is calculated as total dissolved solids (TDS) or, more simply, as electrical conductivity (EC).
What is electrical conductivity (EC), and how is it measured?
Pure water alone is a poor conductor of electricity. Still, its conductivity, i.e., its ability to conduct electricity, increases with the presence of dissolved salts. Measuring electrical conductivity (EC) is a quick, simple, albeit indirect, method of measuring salinity. We can measure electrical conductivity (EC) in both soil samples and aqueous solutions, and it plays a crucial role in hydroponics, serving as an indicator of fertilizer deficiency or excess—special instruments known as conductivity meters measure electrical conductivity in deciSiemens per meter (dS/m).
What is water hardness, and how is it treated?
Salts, primarily calcium carbonate or calcium, contribute to water hardness. Mineral-laden water is a significant problem for producers, as it clogs irrigation pipes, causing substantial damage to the system. Adjusting the salinity and removing Ca++ and Mg++ ions can resolve this problem.
What is pH, and how is it measured?
pH is a measure of how acidic or basic soil, irrigation water, or nutrient solutions are. It is also a factor that affects how well any crop grows. The pH of a nutrient solution is crucial for plant nutrition because it determines the solubility and, therefore, the availability of nutrients to plants. The pH is measured with special instruments called pH meters, which range from 0 (very acidic) to 14 (alkaline), with a neutral value of 7.
Best practices for regulating salinity and pH
We recommend not only controlling the quantity and quality of water required for each irrigated crop but also improving soil porosity.
- To regulate soil salinity, improving soil porosity is a cost-effective, straightforward solution. We achieve this by enriching the soil with organic matter, such as manure and compost. Proper soil cultivation can also prevent water accumulation in certain areas and improve drainage conditions.
- Regulating pH, in practice, requires careful attention and consultation with a specialist. Some indicative solutions include adding limestone or calcium nitrate to acidic soils and sulfur or ammonium sulfate to alkaline soils. Additionally, you can correct the pH in alkaline soils by adding organic fertilizers.
AgriSC recommends salinity and pH correction.
Sulfacid LCN
KSC Sulfacid is a nitrogen-enriched product rich in sulfur that exploits the synergistic action between these two elements. Thanks to LCN technology, which is a nitrification inhibitor complex,
- It regulates the balance between nitrate and ammonium nitrogen.
- It effectively neutralizes carbonates and bicarbonates in irrigation water.
- It effectively combats soil salinity by dissolving easily leached soil salts.
Physiolith Physio Pro
Physiolith Physio Pro uses Calcimer technology, which is a high-quality organic calcium made from ocean materials and includes important trace elements. Due to its structure and high calcium content, we recommend it for
- Rapid pH correction.
- Rapid improvement of soil structure.
Bibliography
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Poulovasilis, A. (2010). Introduction to Irrigation. Embryo Publications, Athens.
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Brandy, C.N., and Weil, R.R. (2015). Soil Science—The Nature and Properties of Soils. Embryo Publications, Athens.