Welcome to ArborWise Tree Management’s Tree Facts Friday. Today we’re talking about chemical fertilization
What is chemical fertilization and why is soil analysis such an important part of that process? James Patterson, a soil scientist with the US government, once said that 90% of urban tree issues stem from soil problems. Urban soil can be like a desert for trees with our landscape practices disrupting their natural nutrient recycling and depleting soil quality. We often remove organic material that could build soil such as fallen foliage which harms both trees and beneficial soil microbes needed for proper nutrition. Many use chemical fertilizers which are popular for quick results like greener foliage and faster growth
Chemical fertilizers are synthetic inorganic compounds created through chemical processes. These fertilizers are specifically designed to supplement plants with the nutrients they need for growth and development. However, unnecessary use of chemical fertilizers leads to a massive impact on soil health, which affects not only the tree, but the surrounding environment. Extensive research indicates that fertilizing with chemicals can harm both trees and soil by killing soil organisms and microbes that are vital for nutrient absorption, which creates further dependency on supplements and treatments. Curiously, research has also shown that high nitrogen fertilization can cause pest infestations, which leads to the need for pesticide use. High nitrogen fertilizers also cause excessive branch growth which results in more mechanical stress and pruning needs as well as disrupting root-to-shoot balance which heightens drought stress.
The only clear guideline for fertilization according to the American National Standards Institute or ANSI is to avoid chemical fertilization unless determined necessary by a laboratory soil analysis. To this point, true nutrient deficiencies are extremely rare even in urban soils. In fact, the ANSI standards tell us that we should consider natural amendments above anything else. The most common reason why urban trees are lacking in nutrition is because the mutualistic soil organisms that facilitate their uptake cannot survive in chemically treated turf grass lawns. Research shows us that we can create better growth and healthier trees just by utilizing compost, mulch, and removing turf grass from the growing area as opposed to chemical fertilization.
We can become informed about this topic just by observing nature. As Jeff Lowenfels says in his book, Teaming with Microbes, no one ever fertilized an old growth forest.
Thanks for joining us for Tree Facts Friday. Please join us again next week for the topic of juvenile pruning. Keep on rocking in the tree world.
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