The actual testing of soil is commonly performed by the farmer or gardener. Gardeners generally purchase test kits which allow very basic analysis to be done on site. PH meters are the most common of this, generally used in conjunction with charts that reveal the PH and nutrient needs of vegetables, flowers and lawns. PH meters are easy to obtain and use. Such testing is used for both adding fertilizer and determining what to plant.
Farmers often send samples to a soil testing lab. These labs hire biology specialists, often trained at agricultural colleges, to perform the analysis. Very detailed testing is done for organic content and levels of nutrients. Potassium and phosphorus are particularly important. Laboratories also check whether soil is contaminated. They may, thus, also receive samples from sites, such as industrial plants, where environmental problems are suspected. Soil testing is important for conservation as well as enhancing the value of agriculture.
Soil testing is used to determine exactly how much of what kind of fertilizer to use and how deep to till the land. In today's scientific agriculture, it is important for ensuring that crops grow and weeds do not, while using no more chemicals than necessary. Methods are also used to analyze water and determine soil moisture levels. Water testing is important both when contamination is suspected and to ensure that fertilizer is staying on the fields, not running off into the watershed. Testing may also indicate whether organic material needs to be added to the soil. Laboratories often classify soils by their natural PH levels and other methods.
Soil testing laboratories will become more important in the future.