There
are many different substances that can be found in topsoil. Each of these
substances in topsoil can be either beneficial or harmful for the topsoil and
for the plants depending upon how much of each substance is in the topsoil. In
this article I will discuss each of these substances and how much of each is
beneficial and/or harmful.
Soluble salts
Soluble
salts are bad for topsoil. If there are unusually high levels of soluble salts,
it will be difficult for the topsoil to absorb water. High levels of soluble
salts actually have direct toxic effects on many plants. Electrical
conductivity of the topsoil solution, or ECe is th3e measurement used to
determine what the level of soluble salt is in topsoil. Soluble salts can be
removed quite easily by over-watering the soil with low salt water. This
removal of soluble salts, or leaching, must be done before anything can be
planted in the topsoil.
The
ideal amount of soluble salt in topsoil is less than 2 dS/m or mmho/cm. If
there is more than 2 dS/m or mmho/cm but less than 4 dS/m or mmho/cm, that is
an acceptable level of soluble salt. However, if there is more than 4 dS/m or
mmho/cm in your topsoil, this is unacceptable, and the topsoil must be drained
of the excess soluble salt. Only certain plants will actually grow in topsoil
that is near 4 dS/m or mmho/cm.
pH Levels
pH
is an indication of what the acidity or the alkalinity, or basic nature, is in
soil. Topsoil pH is measured with a pH electrode. Using a pH electrode to
measure what the pH is of topsoil is the only way to accurately determine the
exact pH of any given soil. There are other means by which people test a soil's
pH, but these ways are not accurate. The way pH works is that a pH of seven is
neutral; that is it is neither an acid nor a base. If the pH is below seven, it
is an acidic substance; while if the pH is above seven, it is a basic or
alkaline substance. In topsoil, if the pH is between 5.5 and 7.5, it is ideal.
If the pH is between 5.0 and 8.2, it is acceptable. If the pH is below 5.0 or
above 8.2, it is unacceptable. Most plants will be able to survive without any
problems in pH levels of 5.0 to 8.2. However, there are some plants that will
not grow in a pH level higher than 7.0. These plants need the acid. Other
plants are extremely susceptible to iron deficiency if they are being grown in
soils with pH levels above 7.7.
It
is practically impossible to change the pH levels in topsoil, so you should
know the pH levels of the topsoil in which you wish to plant, and if such
levels are acceptable for whatever it is you are trying to grow in the topsoil.
Texture
This
is the word used to describe what percentage of the topsoil are clay, sand, and
silt. Ideally, there will be the right amount of each one. This will give the
topsoil the best ability to retain water and nutrients, aerate properly, drain
properly, etc. If there is too much of any of these components, the topsoil
will be unable to sustain life. The acceptable amount of clay is less than thirty
percent. The acceptable amount of sand is less than seventy percent. The
acceptable amount of silt is less than seventy percent. If there is too much of
any of these components, the topsoil will not be able to sustain life. While it
is extremely time-consuming and expensive to change the texture of a large
amount of topsoil, it is possible to add large amounts of whatever is lacking
in the texture to help create a proper balance of each component.
Sodium Adsorption Rate
The
sodium adsorption rate is the amount of sodium relative calcium and magnesium.
Sodium is bad for topsoil, while magnesium and calcium are good for topsoil.
Topsoil with a high sodium adsorption rate generally have bad structure and do
not retain water and nutrients well. They also tend to have high pH levels and
ECe levels. Generally, if the Ph levels and the ECe levels are in check, the
sodium adsorption rate will also be acceptable. If the sodium adsorption level
in topsoil is less than three, it is ideal. Depending on the texture of the
topsoil, a sodium adsorption rate between three and ten would be acceptable. A
sodium adsorption rate of more than ten is unacceptable regardless of the
texture.
Visit www.1800topsoil.com
to learn more about topsoil, gardening, landscaping and to check out our
topsoil calculator.
tweet this!