Most of the time, the average person treats the soil "like dirt". A wise farmer/rancher will care for the soil because he knows that man is dependent on the top 6 inches (15.2 centimeters) of soil. In the plant-animal-soil continuum, soil is often neglected because it does not indicate stress in an obvious way. Animals and plants show physical symptoms but the soil must be looked at more carefully to monitor good health.

Soil that is rich in nutrients is fertile. The expectation of growing plants as food for livestock must include the reality that plants will take nutrients out of the soil. Replacing nutrients is the basic goal of fertilization. Improper fertilization in the past has caused controversy, but the basic premise of fertilization is to replenish the soil.

Soils feed the plants which in turn feed the animals that feed us. Including soil in this important chain will help guarantee its success. Soil provides the support or foundation for plants and most of the nutrients. Soil is accumulated decomposing plant and animal matter with aging parent material. As the soil components break down, elements are released and become available to plants as nutrients. However, naturally this process takes a long time and the soil will only be a result of the parent material, climate, those living organisms once living there, topography, and time. So what is made available to a plant at a certain time may not be exactly what a growing plant needs. Fertilization is supplementing the existing soil with additional, needed nutrients. Fertilizing wisely increases yield, quality (nitrogen content and digestibility), and profits.

There are three basic ways to replenish the nutrients removed from the soil. One way is to recycle nutrients, mainly by way of animal waste. This is a crucial method when discussing pastures. Another way to replenish soils is to obtain and apply fertilizer. And the third way is through microbial action such as nitrogen fixation. Forage-livestock producers should understand and utilize all three for maximum fertility with minimum cost and environmental damage.

Fertilization is an important issue because it is needed in order to produce enough food for the increasing population from the decreasing cultivated land, but too much or inappropriate use can be detrimental to the environment. Part of the debates about fertilizers discuss "man-made" or "chemical" fertilizers as compared to "organic farming". There are many misconceptions about all three terms. This module will look at the various aspects of fertilization so a broader understanding will lead to better fertilization and results.