Summary
Carbonic acid is an option for water pH control that improves soil health and nutrient uptake without the safety and environmental risks of traditional methods.
In agriculture, water quality directly impacts plant health, crop yield, and sustainable farming practices. Among the most critical parameters is water pH, which influences nutrient availability and soil pH. For an optimal water pH level, it should be adjusted to a slightly acidic water range around 6.5. This adjustment improves nutrient availability, reduces the risk of scaling in irrigation systems, and supports healthy soil conditions.
Challenges with High Water pH
High pH water, often containing excessive bicarbonates, presents numerous challenges. The bicarbonates build up in pipes and drip emitters as scale which lower distribution uniformity. High pH water also ties up nutrients. As a result, growers often have to apply more fertilizers.
Growers traditionally rely on sulfur-based methods like sulfuric acid injection and sulfur burners to adjust water pH level. While effective at lowering pH, these approaches carry significant drawbacks. Sulfuric acid requires on-farm storage, posing safety risks such as spills and burns, while sulfur burners emit smoke that irritates farm workers. Both methods can contribute to hyper acidification in irrigation systems and soil, corroding pipes and degrading soil health over time.
These drawbacks raise an important question for growers: What is being added to the soil, and what are its long-term effects? After controlling the pH, what happens to the sulfuric acid? In some cases, added sulfur improves soil conditions, but in others, excessive sulfur can harm plants and disrupt soil chemistry.
The Rainwater Alternative
Carbonic acid, formed when CO₂ fully dissolves in water, mimics the natural acidity of rainwater and offers a gentler approach to pH control. Unlike sulfuric acid, carbonic acid introduces CO₂ into the soil, which increases microbial activity. Enhanced microbial activity may stimulate nitrogen mineralization, providing more plant-available nitrogen and improving overall nutrient uptake.
This is different from bubbling CO₂ because carbonic acid is only formed when the CO₂ is fully dissolved. This process ensures precise and consistent pH adjustment, aligning closely with the needs of both conventional and organic growers. Additionally, carbonic acid eliminates the safety and environmental risks associated with sulfur-based methods, making it an attractive option for long-term sustainability.
Initial field results with Central Valley almond and pistachio growers, and California strawberry growers demonstrate promising outcomes for growers who have adopted carbonic acid for water pH control. Growers report improved soil microbiome activity, enhanced nutrient availability, and healthier crops. Some have reduced fertilizer use, increased their yields, and sprayed less for diseases. Microbial activity is key to healthy soils that support crop production.
The Next Steps
For growers managing high pH water, it’s important to understand the pros and cons of available methods. Beyond pH control, it is important to consider what each method adds to the soil and how it affects long-term soil health and productivity.
If you’re already adjusting your water pH, exploring carbonic acid as an alternative may provide benefits beyond what traditional methods offer. For those who haven’t tested their water’s pH, consulting with an agronomist can reveal opportunities for improvement that align with productive and sustainable agriculture practices.
Actionable Tip:
Did you know that pH probes need to be calibrated every 6-8 weeks? Did you know that pH probes need to stay wet when you’re not using them? A properly calibrated probe is important, so keep your probe wet, even just water in the cap if that’s all you have, and re-calibrate it before use. Buffer solution is very affordable, so keep some in your truck.
