Analysis of soil chemical properties (soil pH)

Soil analysis and fertility evaluation is a reliable and advanced scientific way of evaluating soil via a careful study of its physical, chemical and biological constituents with a view to determine its richness or nutrient deficiency in order to achieve a meaningful conclusion about the status of the soil and a better recommendation are made.

Sample collection and preparation

All the samples were collected with auger, mixed thoroughly together in plastic bucket to obtain a composite sample for the analysis. The sample was collected inside a white polythene leather and each of the samples were labelled accordingly.

The sample is packed into a big leather bag and transported to the laboratory for analysis. Upon reaching the laboratory, the samples were exposed to dry before commencement of the analysis. The drying process took about a week.

SOIL pH: Soil pH significantly influences other soil chemical properties as well as biological organisms. The availability of most of the chemical elements are of importance to plants and microbes are greatly affected by soil pH. There is a relationship between pH and the level of base-forming cations (Ca2+, Mg2+,K+ and Na+) i.e. the reduction in acidity and an increase in alkalinity will encourage high levels of these exchangeable base forming cations. Likewise, the tendency of these toxic elements such as iron (Fe), manganese (Mn) and Aluminum (Al) to be established at low pH.
The tolerance of different soil microbes to soil acidity and alkalinity varies. Most general purpose bacteria and actinomycetes function best at intermediate and high pH value. Therefore, to determine the precise management practices (i.e. liming and fertilizer application) to carry out on a particular agricultural land, the need for soil pH is inevitable. The United States Department of Agriculture Natural Resources Conservation Service classified soil pH ranges as follow

Ultra acidic
< 3.5

Extremely acidic
3.5 ‒ 4.4

Very strongly acidic
4.5‒5.0

Strongly acidic
5.1‒5.5

Moderately acidic
5.6‒6.0

Slightly acidic
6.1‒6.5

Neutral
6.6‒7.3

Slightly alkaline
7.4‒7.8

Moderately alkaline
7.9‒8.4

Strongly alkaline
8.5‒9.0

Very strongly alkaline

9.0

                           SOIL pH ANALYSIS.

AIM: To determine the pH values of the soil samples from both dry land(upland) and wetland(lowland).
APPARATUS: Glass-electrode, pH meter, electric weighing scale, 50ml beaker, glass rod.

REAGENTS USED:
0.01ml of calcium chloride (CaCl2)
Distilled water
SOIL pH IN WATER:
PROCEDURES:
10g of soil sample from both areas was weighed each using electronic weighing scale into 2 separate rinsed labeled 50ml beakers (indicating either lowland or upland) .
10ml of water was added to the samples to prepare a 1:1 suspension.
The suspension was stirred thoroughly using a rinsed glass stirring rod and left undisturbed for 30 minutes.
After 30 minutes, the suspension was stirred continuously.
The electrode was rinsed and dipped into a buffer solution and the pH meter was calibrated to 7.
The electrode was rinsed with distilled water and dipped into the suspension to take the level of soil pH in water. The electrode was rinsed before been dipped into the other suspension.

RESULTS: Soil pH measured in water for upland (dry land) is 4.61 i.e. very strongly acidic using the pH scale in table 3 while
Soil pH measured in water for lowland (wet land) is 5.71 i.e. moderately acidic using the pH scale in table 3