Note: This page is no longer being maintained and is kept for archival purposes only.
For current information see our main page.
Garden with Insight Kurtz-Fernhout Software
Developers of custom software and educational simulations.
Home ... News ... Products ... Download ... Order ... Support ... Consulting ... Company
Garden with Insight
Product area
Help System
Quick start

Garden with Insight v1.0 Help: pH

pH is an index that measures the number of H+ ions in the soil solution (H+ ions adsorbed to micelles are not counted). The higher the number of H+ ions, the lower the pH.

In this program the model of pH, cation exchange capacity (CEC), and base saturation (BSA) is very simple. These properties are changed only by fertilization and nitrogen fixation by plants (both of which decrease pH) and by pH control measures (liming and sulfur application). Simulated pH affects nitrification (conversion of ammonium ion to nitrate ion by aerobic soil bacteria) and flow of phosphorus between labile and mineral phases.

In reality pH, CEC and BSA depends on many factors, including: seasonal changes, soil organic matter (its amount and acidity), leaching of cations and anions, plant root activity (plants release H+ ions during respiration, which displace basic cations from cation exchange sites), the local climate, soil texture, soil mineral deposits, and living organisms in the soil. And pH affects many processes in the soil, including the abundance of microbes, invertebrates and vertebrates in the soil, cation exchange capacity, leaching of nutrients, and uptake of various nutrients needed by plants.

How it works:
auto pH control
increasing acidity due to fertilizer

Home ... News ... Products ... Download ... Order ... Support ... Consulting ... Company
Updated: March 10, 1999. Questions/comments on site to
Copyright © 1998, 1999 Paul D. Fernhout & Cynthia F. Kurtz.