What is soil pH and how do we improve it?
What is soil pH and how do we improve it?
How do we find the ph of a soil and when is it problematic for plant growth? Many times we wonder if the soil in our garden or field is suitable to grow the vegetables, herbs, trees and shrubs we desire. Soil acidity, i.e. how acidic or alkaline the soil is, is one of the most basic parameters to assess its suitability for a specific crop. The determination of acidity is included in the determination in the general soil analysis that captures its basic characteristics. The most common and easy way to measure the acidity of soil, water and various liquids is the pH scale. Taking into account the pH value, we can proceed to improve the soil with the appropriate soil improvement materials. So let’s see how we measure pH, what types of soil exist according to the scale, and how to correct the pH for smooth growth and abundant fruiting.
What is soil pH?
pH is a measure of soil acidity that was discovered in the early 20th century. It has a direct effect on plant growth, as it affects the uptake of nutrients by plants. At a very low or very high pH, there are unfavorable natural conditions in the soil to the extent that plants find it difficult to assimilate the various nutrients elements and toxicities occur.
How are soils classified according to the pH scale?
The pH method involves a calibration of acidity from 0 to 14, where 7 is neutral. Depending on the determination of pH, soils are characterized as:
- Very strongly acidic soil, when the pH value is less than 5.
- Strongly acidic soil, when the pH value is between 5 and 5.5.
- Moderately acidic soil, when the pH value is between 5.5 and 6.
- Slightly acidic soil, when the pH value is between 6 and 6.5.
- Neutral soil, when the pH value is between 6.5 and 7.5.
- Slightly alkaline soil, when the pH value is between 7.5 and 8.
- Moderately alkaline soil, when the pH value is between 8 and 8.5.
- Strongly alkaline soil, when the pH value is between 8.5 and 9.
- Very strongly alkaline soil, when the pH value is from 9 and above.
In summary, alkaline soils have a pH above 7, while acidic soils have a pH of below 7. 3.
How does pH affect soil nutrients?
In a range of values from 6 to 8 most of the cultivated plants grow smoothly and do not face a problem. , phosphorus, potassium, calcium and magnesium, as well as trace elements such as boron, iron and zinc.
In more alkaline soils with a higher pH, there is a lack of nitrogen and trace elements and higher concentrations of phosphorus, potassium and calcium. In more acidic soils with a lower pH, the availability and absorption of key nutrients such as nitrogen, phosphorus and potassium is reduced. Of course, there are also acidophilic plants (such as gardenia and azalea) which they grow best at very low pH values between 4 and 5.
In what ways can we measure soil pH?
There are three ways to measure soil pH:
- With soil analysis: The most reliable way to measure soil pH is to take a soil sample to a soil laboratory as part of it soil analysis. This way, we get the best result and can measure with
greater accuracy. - With a height meter: There are special electronic devices on the market that they are called depth meters, which have an electrode that we sink into the ground and digital display showing the pH measurement. Depending on the cost of each device, the reliability of the results can it differs.
- With paper strips: An economical way to measure soil pH, are the special disposable paper strips that change color depending on its pH ground.
How can we correct soil pH for crops?
Correcting and improving soil pH falls into two main categories:
The increase of pH in acidic soils and the reduction of pH in alkaline soils using the appropriate soil improvement materials as described in detail below:
- Improving acidic soils by increasing pH
- To correct the pH in very acidic soils, we add an appropriate amount of agricultural lime to raise the pH and improve the soil.
The high acidity of soils is enhanced by the excessive use of fertilizers, intensive cultivation without fallow, and the depletion of soil nutrients due to intensive rainfall. Improving Alkaline Soils with Ph Reduction To correct the pH of alkaline or calcareous soils, we add an appropriate amount of sulfur powder to the soil to lower the pH.Depending on the amount of sulfur we pour into each square meter of soil, we achieve a corresponding level of soil pH reduction. Adding ammonium sulfate and iron sulfate fertilizers helps to lower the pH. In addition, correcting the pH in alkaline soils can be done with organic fertilizers such as manure, compost and peat moss.
And a secret for easy soil pH measurement.
A very easy but not so accurate measurement of soil pH is to put soil in a glass containing vinegar and a glass containing 2 tablespoons of baking soda dissolved in water.
If the glass with vinegar foams, then the soil is alkaline and if the glass with baking soda foams, the soil is acidic.