Soil testing. A pH meter showing a neutral pH of soil. Farmers and gardeners use pH meters to determine the pH level of soil to assess its suitability for different plants. A probe placed in the soil measures the amount of free hydrogen ions present,giving a value on the pH scale. A pH of 7 is neutral,above 7 is alkali and below 7 is acid. This meter displays a pH of 6-7,meaning that this is a neutral soil. Some plants are intolerant of acid or alkaline soils,and the pH has to be corrected towards this normal level. For a sequence of pH tests for acid,neutral and alkaline soils,see images E770/1157-1159 | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Terry, Sheila |
Taille de l’image : | 4917 px × 4008 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |