(Picture from http://www.icarda.org)
The idea that one could test or analyze a soil and obtain some information about its properties especially its acidity or alkalinity and its nutrient status is long established, and can be traced back to the beginning of scientific inquiry about the nature of soil. Analysis of plant to reflect fertility status of the soil in which it grew is more recent, although visual crop observations are as old as the ancient Greeks, if not older. In the last few decades, spurred on by commercialization of agriculture and the demands for increased output from limited and even diminishing land resources, both soil and plant analysis procedures have been developed, and are still evolving.
With the advent of chemical fertilizers, the need to know nutrient status of a soil in order to use these expensive and limited inputs more effectively became all the more crucial. However, if soil testing is to be an effective means of evaluating fertility status of soils, correct methodology is absolutely essential. A soil or a field may be assessed for its capability of providing a crop with essential nutrients in several ways:
- Field Plot Fertilizer Trials;
- Greenhouse Pot Experiments;
- Crop Deficiency Symptoms;
- Plant Analysis;
- Rapid Tissue or Sap Analysis;
- Biological Tests, such as Growing Microorganisms; and
- Soil Testing prior to Cropping
