Soil is important for plant growth and development and helps to increase the food production and productivity of crops. Hence maintainance of soil health is an important task in the field of agriculture because soils are heterogeneous in nature. Soil has to be studied and analyzed for the various Physical, Chemical and biological properties that help to maintain the fertility of the soil. The best method to study the soil is soil sampling and nutrient analysis.
A soil test is a process by which elements (phosphorus, potassium, calcium, magnesium, sodium, sulfur, manganese, iron, copper and zinc) are chemically removed from the soil and measured for their "Plant available" content within the sample. The quantity of available nutrients in the sample determines the amount of fertilizer that is recommended. A soil test also measures soil pH, humic matter and exchangeable acidity.