ABSTRACT
Soil fertility is a scientic discipline that integrates the basic principles of soil biology, soil chemistry, and soil physics to develop the practices needed to manage nutrients in a protable, environmentally sound manner. Historically, the study of soil fertility has focused on managing the nutrient status of soils to create optimal conditions for plant growth. Fertile, productive soils are vital components of stable societies because they ensure that we are able to grow the plants needed for food, ber, animal feed and forage, medicines, industrial products, energy, and for an aesthetically pleasing environment. Beyond management of soil nutrients, the study of soil fertility rests on two other fundamental principles. First, optimum nutrient status alone will not ensure soil productivity. Other factors such as soil moisture and temperature, soil physical condition, soil acidity and salinity, and biotic stresses (disease, insects, weeds) can reduce the productivity of even the most fertile soils. Second, modern soil fertility practices must stress environmental protection as well as agricultural productivity; that is, we must prevent the pollution of our soils, air, and water as we strive to optimize the nutrient status of soils for plant growth.
