2. • What is ph ?
• What is soil ph ?
• How does soil ph affect soil growth
?
• How to measure soil ph ?
• Symptoms of Soil Acidity
• How does soil ph change ?
• How to restore soil ph ?
• Soil Permeability
• Factors affecting soil permeability
• Measurement of Soil permeability
• Percolation Rate

3. • pH is the measure of acidity. More
correctly it is the measure of
the potential of Hydrogen ions.
• The higher the concentration of
hydrogen ions in the soil, the lower the
pH and vice-versa.
• The level of acidity (low pH) or
alkalinity (high pH) is measured on a
scale of 1 to 14 with 7 being neutral.
• For instance, pH of:
caustic soda = 13.8
seawater = 8.0
soft drink = 2.8 etc.

4. • Soil pH is an indicator of the
acidity or alkalinity of a soil.
• Extremes in pH level may affect
the plant growth.
• Some plants can grow over a wide
range of pH; others are sensitive to
acidity or alkalinity.
• Soil pH is affected by soil
chemistry and soil biology.
• It is also affected by the physical
characteristics of the soil via
aeration of soil and soil water.

5. • At extreme pH, the availability of some nutrients is decreased.
E.g.: phosphorous and molybdenum at low pH and zinc at high
pH.
• Solubility of elements is toxic to the plants is increased. E.g. :
aluminium and manganese at low pH.
• Extremes in pH level may also affect the production of many
plant species and may disturb the symbiotic relationship with
Rhizobia.
• In alkaline soils where the trace elements
iron, manganese, copper, zinc and boron, so readily available in
acid soils, may be unavailable to plants, even though they are
present in the soil in adequate amounts, and molybdenum is
readily available.

6. • In laboratories, soil pH may be measured by using
prepared sample of soil and a pH probe.
• On the site, the soil pH is measured using a
colorimetric kit and a fresh sample of soil.

7. • Nodulation failure of legumes - reddening of stems and
petioles on pasture legumes, or yellowing and death of oldest
leaves on grain legumes indicate nitrogen deficiency.
• Deficiency symptoms of
sulphur, phosphorus, molybdenum, calcium or magnesium.
• Root growth poor, with stubby roots and few fine roots.
• Crop yields / pasture growth are poor even in good seasons.

8. • Agricultural activities often
decrease the soil pH of soil which is
also called acidification.
• Some processes involve in
acidification of soil are :
i. Sowing annual dominant pastures.
ii. Cropping with legumes.
iii. Application of nitrogen fertilizers.
iv. Product removal, especially hay
and grain.

9. • The most common way of regaining the soil pH is by adding agricultural/quick
lime.
• Successful use of lime occurs where the farmer:
 Knows the target pH for the plants being grown.
 Incorporates lime by cultivation.
 Matches the quantity and quality of lime with amount needed for the pH
buffering capacity of the soil.
 Can get it on the ground at a sufficiently cheap price.
• Other important factors include:
 The type of lime
 Cost
 Plant response
 Timing
 Application method
 Soil texture
 Organic matter content

10. • Soil permeability is the property of the soil to transmit
water and air and is one of the most important qualities to
consider for fish culture.
• The more the permeability of the soil, the greater the
seepage.
• Some soils are so much permeable that it is not possible to
build a pond without special construction technique.
• The soil is divided into many layers and each layer has
different soil permeability.

11. • Many factors affect soil permeability such as:
1. soil texture
2. structure
3. layering
4. consistency
5. color
6. holes/spores
7. depth
SOIL TEXTURE PERMEABILITY
CLAYEY FINE VERY SLOW
LOAMY MODERATE MODERATE
SANDY COARSE RAPID

12. • Soil permeability is generally measured in :
1. Centimeters per hour (cm/h)
2. Millimeters per hour (mm/h)
3. Centimeters per day (cm/d) etc.
• It is also measured in terms of coefficient of permeability in meters per
second (m/s) or in centimeters per second (cm/s).
• In fields, soil permeability can be measured by:
i. The visual evaluation of the permeability rate of soil horizons.
ii. A simple field test for estimating soil permeability.
iii. A more precise field test measuring permeability rates.

13. • Perculation rate is the measurement of the
permeability.
• It is expressed in the terms:
amount of water/time taken to perculate = ml/sec