Healthy roots (along with nutrition and management) lead to a more robust, healthy tree that is better able to withstand stress and disease.
Four out of the five plant hormones are made by the roots, and the pathway for water and nutrients starts with the little white root hairs attached to the feeder roots.
Weak roots lead to weak trees and poor tolerance to stress.
Farmers and agronomists have gained most of their knowledge about roots by studying vegetables.
It is easy to pull out a vegetable and look at the roots. If there is a mass of white healthy roots to be seen then chances are, we have a healthy plant.
Dig and discover
This is a little harder to do with trees, but having a dig in the root zone can uncover a lot of information.
Root growth can be impaired by nutrient imbalance, disease and nematode attack, and even more commonly, too little or too much water.
It is imperative that someone is digging around in the root zone of your trees, especially at critical growth stages. If there is no fresh white root growth, then action is required.
Roots are the ‘brains’ of the plant
Crop scientists at Stoller refer to the roots as the brains of the plant. The root zone is like the control centre for the tree.
Besides being an important site for water uptake, nutrient uptake and hormone production, the roots are where signals and regulation of all plant parts take place.
Proteins and hormones move around the plant triggering growth responses in shoots, fruits, roots and leaves.
Stable environment needed
Roots are sensitive to temperature change and moisture variation, so we want them to grow in a stable environment with not all the root mass in one place or near the soil surface.
When the roots shut down, the signals are not moving in the plant.
Temperature
Temperature is important depending on tree variety, soil type etc.
Roots have optimal temperature ranges for growth. There is little root growth below about 15C.
Water
Some trees are more, or less sensitive to drought and flooding, and some trees will die after only a couple of days of waterlogging.
There is no point applying nutrients to the root zone if roots are not functional. Many nutrients such as nitrates will move from the root zone quickly and never be absorbed.
Where do roots get their food?
When asked this question, most people say that the roots get their food from the fertiliser and nutrients applied to the soil.
The truth is that roots get their food from the leaves.
(continued next issue)
Contact Stoller Australia phone 1800 FERTILISER (1800 337 845)
email:
www.stoller.com.au
See this article in Tree Fruit Nov 2015
