Trees are Vital
Fertilizing Trees & Shrub
plants grow best in mineral soils with a slightly acid
reaction. In this range, most plant nutrients are at or
near their high solubility. Generally, plants take up
nutrients only if they are dissolved in the soil
solution, so if the nutrients are in the soil solution
they are available for plant uptake. In Soils which are
strongly acid (pH4.0 - 5.0),
aluminum, is a compound of clay, is very soluble and
dissolves more readily. As levels of dissolves aluminum
increases, a chemical reaction occurs with phosphorus
compounds, making them insoluble and unavailable to
plants. If the dissolves aluminum levels become too
high, toxic levels are reached and plants die.
soil pH is moderately alkaline
(pH> 8.0), the solubility of many nutrients
decreases. Phosphorus as an example becomes less soluble
as the pH increases. Iron, Magnesium, Zinc and Copper
also become insoluble and unavailable to plants.
pH can also influence plant growth by its effects the
activity of beneficial soil based microorganisms that
build soil structures, cycle organic matter or fix
nitrogen in the soil.
pH can also have a significant effect on the performance
and breakdown of many pesticides. Bacteria that
decompose soil organic matter are hindered in strong
acid soils. This prevents organic matter from breaking
down, resulting in an accumulation of organic matter and
the tie up of nutrients particularly Nitrogen, that are
held in the organic matter. Phosphorus, Potassium,
Calcium and Magnesium also become insoluble in the high
Some plants do well in moderate to high acid soils,
while other plants are more tolerant in alkaline soils.
Alkaline tolerant plants do not do well in acid soils
and acid loving plants can not live in alkaline soils
and in both cases they become chlorotic, the inability
to absorb sufficient nutrients. It is usually best to
use plants that grow well in your particular area,
according to your soil conditions.