Liquid calcium products have been around for a long time. The vast majority of these products are either a calcium chloride or chelated calcium base which is now commonly found with the addition of a humic acid, microbial, or micronutrient. Many of these make promises such as “raises your soil pH with natural, regenerative, liquid calcium fertilizers that correct soil pH quickly, efficiently, and affordably!”. From a soil chemistry aspect the promise of adding 3 to 5 gallons of a Ca solution, which is approximately 10% Ca, will raise the soil pH is impossible on a mass balance approach. In this I mean that to increase the pH of an acid soil {soil pH is the ratio of hydrogen (H) and hydroxide (OH) in the soil, and having an acid soil means the concentration of H is greater than that of OH} requires a significant portion of the H+ that is in solution and on soil particle to be converted to OH, or removed from the system entirely.

The blog below walks through the full chemical process of liming a soil but in essence to reduce the H+ concentration we add a cation (positively charged ion) such as Ca or magnesium (Mg) which will kick the H+ of the soil particle and a oxygen (O) donator such as CO2 with ag lime or (OH)2 which is in hydrated lime. Each of these O’s will react with two H’s to make water. And with that the pH increases.

Mechanics of Soil Fertility: The how’s and why’s of the things.

However regardless of the chemistry, there is always a lot of discussion around the use of liquid calcium Therefore we decided to dig into the question with both field and laboratory testing. This blog will walk through the lab portion.

This was a laboratory incubation study. The objective was to evaluation the impact of the liquid Ca product (LiqCa**) on the soil pH, buffer capacity, Ca content and CEC of two acidic soils. LiqCa was applied at three rates to 500 g of soil. The three rates were equivalent to 2, 4, and 6 gallon per acre applied on a 6” acre furrow slice of soil. One none treated check and two comparative products were also applied. HydrateLime (CaO) as applied at rate of Ca equivalent to the amount of Ca applied via LiqCa, which was approximately 1.19 pounds of Ca per acre. Also AgLime (CaCO3) was applied at rates equivalent to 1, 2, and 4 ton effective calcium carbonate equivalency (ECCE). The Ag lime used in the study had a measured ECCE of 92%. The two soils selected for both acidic but had differing soil textures and buffering capacities. The first LCB, had an initial soil pH (1:1 H2O) of 5.3 and a texture of silty clay loam and Perkins had a initial pH of 5.8 and is a sandy loam texture. Both soils had been previously collected, dried, ground, and homogenized. In total 10 treatments were tested across two soils with four replications per treatment and soil. 

Project protocol, which has been used to determined site specific liming and acidification rates, was to apply the treatments to 500 grams of soil. Then for a period of eight weeks this soil wetted and mixed to a point of 50% field capacity once a week then allowed to airdry and be mixed again. At the initiation and every two weeks after soil pH was recorded from each treatment. The expectation is that soil pH levels will change as the liming products are impacting the system and at some point, the pH reaches equilibrium and no longer changes. In this soil that point was week six however the trail was continued to week eight for confirmation. See Figures 1 and 2.

ANOVA Main effect analysis showed that Soil was not a significant effect so therefore both soils were combined for further analysis. Figure 3 shows the final soil pH of the treatments with letters above bars representing significance between treatments. In this study all treatments were significantly greater than the check with exception of LiqCal 2 and CaO 6. Neither LiqCal or CaO treatments reached the pH level of Aglime, regardless of rate.

Summary

The incubation study showed that application of LiqCal at a rate of 4 and 6 gallons per acre did significantly increase the soil pH by 0.1 pH units and 6 gallons per acre increased the Buffer index above the check by 0.03 units. Showing the application of LiqCal did impact the soil. However the application of 1 ton of Ag lime resulted in significantly great increase in soil pH, 1.0 units by 8 weeks and a buffer index change of 0.2 units. The Aglime 1 was statistically greatly than all LiqCal treatments. Ag lime 2 and 4 were both statistically greater than Ag lime 1 with increasing N rate with increasing lime rate. Given the active ingredient listed in LiqCal is CaCl, this result is not unexpected. Ag lime changes pH by the function of CO3 reacting H+ in large quantities. In a unsupported effort a titration was performed on LiqCal, which show the solution was buffered against pH change. However it was estimated that a application of approximately 500 gallons per acre would be needed to sufficiently change the soil pH within a 0-6” zone of soil.

Results of the field study.
https://osunpk.com/2025/06/02/field-evaluation-of-lime-and-calcium-sources-impact-on-acidity/

Take Home

The application of a liquid calcium will add both calcium and chloride which are plant essential nutrients and can be deficient. In a soil or environment suffering from Cl deficiency specifically I would expect an agronomic response. However this study suggest there is no benefit to soil acidity or CEC with the application rates utilized (2, 4, and 6 gallon per acre).

** LiqCal The product evaluated was derived from calcium chloride. It should be noted that since the completion of the study this specific product used has changed its formulation to a calcium chelate. This change however would not be expected to change the results as the experiment did include a equivalent calcium rate of calcium oxide.

Other articles of Interest

https://extension.psu.edu/beware-of-liquid-calcium-products

https://foragefax.tamu.edu/liquid-calcium-a-substitute-for-what/

Any questions or comments feel free to contact me. b.arnall@okstate.edu