The Quality of Irrigation Water and Its Impact on Crops

Access to irrigation water in both quantity and quality is a critical factor for agriculture; however, it increasingly poses a greater challenge for farmers to have access to this resource. In Mexico, a significant portion of agricultural areas faces water quality issues, such as pH, salinity, alkalinity (carbonates and bicarbonates), and specific element problems (sodium, boron, chloride, etc.).
When a producer encounters one or more of the aforementioned issues, managing fertigation becomes a challenge due to the negative impacts it has on crop development and potential damage to the irrigation system’s pipes and injectors.

pH and Water Alkalinity

pH measures the concentration of hydrogen ions (H⁺) and hydroxide ions (OH^–) in water. A higher concentration of H⁺ ions results in lower pH (acidic), while a higher concentration of OH^– ions leads to higher pH (basic). In fertigation, pH plays a crucial role in improving nutrient use efficiency because some nutrients are not available at certain pH levels or are prone to reacting with other elements, causing precipitates and/or blockages in the irrigation system.

High pH limits the availability of nutrients such as phosphorus, iron, zinc, and manganese, often associated with alkalinity. Alkalinity refers to the presence of carbonates (CO₃^–) and bicarbonates (HCO₃^–). When high pH combines with alkalinity, chemical reactions (precipitates) can occur, blocking nutrients and rendering them unavailable to plants.

Common precipitates formed in alkaline water with high pH include calcium phosphate, magnesium phosphate, iron phosphate, calcium carbonate, and magnesium carbonate. These elements, when part of these compounds, are unavailable to plants and, being insoluble, can deposit in pipes and drip emitters, causing clogging and obstruction. In this scenario, the selection of fertilizers, especially phosphatic ones, plays a crucial role in improving phosphorus use efficiency.

ICL’s Innovative Solution

Common phosphatic fertilizers such as Mono-Ammonium Phosphate (MAP), Mono-Potassium Phosphate (MKP), and their derivatives are challenging to handle in waters with alkalinity and high pH, as they pose a high risk of precipitates with the calcium present in the water or when mixed with fertilizers containing calcium and/or magnesium.

The fertilizer PeKacid 0-60-20 presents an innovative solution to address nutrient blockage and precipitation problems. It not only provides pure phosphorus and potassium to plants but also offers multiple advantages that help producers improve fertilizer efficiency and care for the irrigation system. The advantages of PeKacid include:

• A unique phosphorus fertilizer that does not form precipitates with calcium.
• Superior solubility of up to 670 g/L at 20 °C.
• High nutrient concentration: 60% P₂O₅ and 20% K₂O.
• Nutrient unlocking power for P, Ca, Fe, Mn, Zn.
• Desalination power, improving the absorption of other nutrients.
• High acidifying power, reducing pH to 2.2 at 1% concentration.
• Prevents and unclogs irrigation emitters.
• Eliminates HCO₃ and CO₃; 240 g neutralizes 1 equivalent of HCO₃ in 1 m3 of water.
• Can be used as a pH buffer in foliar applications.
• Enhances the efficacy of herbicides.

Due to its numerous benefits, PeKacid acidifying fertilizer is an ideal solution for improving nutrient use efficiency and mitigating issues related to high pH and water alkalinity in irrigation.