The plant is the most important part in crop production. The roots of the plants spread through soil, absorb water and minerals which are transported to the stem, branches and leaves. They also give firm anchorage to the plant and in addition accumulate nutrients. As important as this may seem it is surprising that the roots are the least known about, the least understood and the least appreciated part of a plant. This is undoubtedly true to the fact that they are “out of sight and out of mind”.
Three types of roots can be found. Feeder roots are responsible for the absorption of water and minerals. These roots are the smallest and the most neglected.
The feeder roots are found in the upper regions of the soil profile. The Oxygen roots are as their name imply, responsible for the oxygen in-take in plants. They are differentiated and also found close to the surface of the soil.
The structural roots anchor the plant. These roots are the main reason for the misconception that exists leading to ineffective irrigational methods. This misconception occurs due to the fact that these roots are normally found in the deeper soil regions and farmers tend to irrigate heavier and longer to enable water to reach the structural roots.
This method however is not efficient as it is the feeder roots that perform the vital task to supply water and minerals to the plant. Ninety percent of all nourishing roots are found in the upper 150mm of soil, therefore it should be evident that irrigation cycles should be shorter and at regular intervals because we tend to over-estimate root depth. Because we irrigate too much too long per cycle we tend to develop saturated conditions in the deeper soil profile. This leads to little water being optimally used by the feeder roots. Conditions of over-irrigated underground develop which ultimately leads to inferior water and oxygen intake. The importance of oxygen and water intake is vital to the absorption of minerals of the plant. Needless to say that the saturated conditions imply that essential minerals do not get transported to the plant. Soil-born diseases are also a function of Oxygen intake in the plant.
It clearly seems that a thorough understanding of the activities of a plant both above ground and below ground and the ways in which these activities can be influenced by various agricultural practices should form the foundation of cultivation. Not until the mechanism by which the soil and the plant are brought into favorable relationship, will the root system be clearly understood.