Understanding Soil pH Adjustment with Lime and Sulfur

Understanding Soil pH Adjustment with Lime and Sulfur

If you prefer watching to reading, here is the link to the SoiLab YouTube video covering the study referenced in this article. 

This article delves into a three-month study on adjusting soil pH using various amendments. The experiment examines how calcitic and dolomitic lime affect acidic soils, while elemental sulfur and citric acid are tested on basic soils. With 180 soil tests conducted across four unique soil types and treatments, the study offers insights into effective pH management for lawns and gardens.

 

Key Findings:

Acidic Soils (pH Increase):

Both dolomitic and calcitic lime effectively raise pH in very acidic soils (starting pH 4.28), but the effect diminishes over time, suggesting the need for split applications (e.g., spring and fall).

Calcitic lime showed slightly more rapid and lasting activity than dolomitic lime.

 

Slightly Acidic Soils (pH Increase):

Similar trends were observed in acidic soils (starting pH 6.06), with lime initially increasing pH, followed by a gradual decline.

The untreated control (irrigated with slightly acidic water) remained relatively stable, indicating minimal change without amendments.

 

Basic Soils (pH Decrease):

In basic soils (starting pH 7.49), citric acid showed limited long-term impact, suggesting multiple applications within a season are necessary.

Elemental sulfur effectively lowered pH, albeit slowly, also indicating the need for repeated applications over time.

The untreated control saw a natural pH decrease due to slightly acidic irrigation water.

 

Very Basic Soils (pH Decrease):

The highly buffered, very basic soil (starting pH 8.36) proved most resistant to change. No significant differences were observed among treatments, highlighting the need for persistence, experimentation with different amendments, and repeated applications across seasons.

 

Key Takeaways:

Irrigation Water Matters: The pH of irrigation water significantly impacts soil pH, either aiding or hindering adjustment efforts.

Split Applications: Single amendment applications may not provide lasting results. Consider split applications in spring and fall or multiple applications within a season (especially with citric acid).

Annual Monitoring: Regular soil pH testing is essential to track progress and adjust treatment strategies. The MySoil test kit is a great solution with additional guidance on nutrition management and seasonal reminders.

Experimentation: Success in pH adjustment requires ongoing experimentation and monitoring to find a program that works for specific soil conditions.

 

Conclusion:

The study underscores the importance of understanding soil type, selecting appropriate amendments, and implementing consistent monitoring and application strategies to achieve and maintain optimal soil pH for thriving lawns and gardens. The video is linked here for viewing.

 

Keywords: soil pH, lime, sulfur, soil amendment, citric acid, dolomitic lime, calcitic lime, gardening, lawn care, SoiLab