1. What is Soil pH?

Soil pH is a measure of the acidity or alkalinity of soil, determined from soil-water slurry measurement. It indicates the concentration of hydrogen ions [H⁺] in the soil solution and is expressed as a dimensionless value.

2. How Does the Calculator Work?

The calculator uses the pH formula:

Where:

• \( pH \) — Soil pH (dimensionless)
• \( [H^+] \) — Hydrogen ion concentration (mol/L)

Explanation: The pH scale is logarithmic, meaning each whole pH value below 7 is ten times more acidic than the next higher value.

3. Importance of Soil pH Measurement

Details: Soil pH affects nutrient availability, microbial activity, and plant growth. Most plants prefer a pH range between 6.0 and 7.5 for optimal growth.

4. Using the Calculator

Tips: Enter hydrogen ion concentration in mol/L. The value must be greater than 0. The calculator will compute the corresponding pH value.

5. Frequently Asked Questions (FAQ)

Q1: What is the ideal pH range for most plants?
A: Most plants grow best in slightly acidic to neutral soil with pH between 6.0 and 7.5.

Q2: How is hydrogen ion concentration measured in soil?
A: Typically measured using a soil-water slurry with a 1:1 or 1:2 soil-to-water ratio, then analyzed with a pH meter or indicator.

Q3: What factors affect soil pH?
A: Parent material, rainfall, vegetation type, fertilizer use, and decomposition of organic matter can all influence soil pH.

Q4: How often should soil pH be tested?
A: For agricultural purposes, soil pH should be tested every 2-3 years, or more frequently if amending soil acidity/alkalinity.

Q5: Can pH values be negative or above 14?
A: While theoretically possible with extremely concentrated acids or bases, most natural soils have pH values between 3.0 and 9.0.