In crop production, plants synthesize nutrients in the soil such as nitrogen, phosphorus, and potassium with air, sunlight, and water. Without proper management, continuous crop production can reduce nutrient reserves in the soil and over time this reduction can limit productivity and yield, and lead to soil degradation.
Techniques to conserve and add nutrients to the soil through the application of organic and inorganic fertilizers can help to maintain and increase the nutrient reserves of the soil. However, an oversupply of nutrients can also be a problem causing production inefficiency, pollution and potential damage to plants themselves.
Achieving a balance between the nutrient requirements of plant populations and the nutrients available in soils is essential for maintaining high levels of productivity and soil fertility. In many cases, imbalances can be corrected through soil testing and integrated fertilizer application.