1. What is pH?

pH is a measure of the acidity or alkalinity of a solution, defined as the negative logarithm (base 10) of the hydrogen ion concentration. In soil science, pH measurement from soil-water extract is crucial for understanding soil health and nutrient availability.

2. How Does the Calculator Work?

The calculator uses the pH formula:

Where:

• \( [H^+] \) — Hydrogen ion concentration (mol/L)
• \( \log \) — Logarithm base 10

Explanation: The pH scale ranges from 0 to 14, with 7 being neutral. Values below 7 indicate acidity, while values above 7 indicate alkalinity.

3. Importance of Soil pH Measurement

Details: Soil pH affects nutrient availability, microbial activity, and plant growth. Most plants prefer a pH between 6.0 and 7.5. Extreme pH values can indicate soil problems that need correction.

4. Using the Calculator

Tips: Enter the hydrogen ion concentration measured from a soil-water extract in mol/L. The value must be greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: Why measure pH from soil-water extract?
A: Soil-water extract provides a standardized method for pH measurement that allows for comparison between different soil samples and laboratories.

Q2: What is a typical pH range for agricultural soils?
A: Most crops grow best in soils with pH between 6.0 and 7.0, though some plants have specific preferences outside this range.

Q3: 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 pH or noticing plant growth problems.

Q4: What factors can affect soil pH?
A: Parent material, rainfall, vegetation, fertilizer use, and decomposition of organic matter can all influence soil pH over time.

Q5: How can soil pH be adjusted?
A: Lime is commonly added to raise pH (reduce acidity), while sulfur or aluminum sulfate can be added to lower pH (increase acidity).