Experimental Study: Soil Sampling

 SOIL SAMPLING 

AIM

An experimental study to understand how soil sampling is done, the types and techniques involved. 

INTRODUCTION 

Soil sampling is the process of extracting a small volume of soil for subsequent analysis at the laboratory. The results obtained can be used to measure the concentration of certain metals in the soil, nutrients and other parameters that are useful for agriculturalist to identify if a plot of land is good for farming activities, and the kind of crops to cultivate. 

In sampling, each sample collected must be a true reflection of the area being sampled. 

The bulk density of soil can be determined through sampling process which will enable the technician to find out how good the soil is for agricultural activities. Soil sampling is the most important procedure used to understand the nutrient status of the land. 

A good procedure that give actual representation of soil is the collection of several individual soil samples over the designated area and combining them to form a composite sample analysis. The test results of the analysis is useful in defining the nature of soil on a land. 

TYPES AND TECHNIQUES OF SOIL SAMPLING 

• RANDOM SAMPLING 

In this type, soil samples are selected or collected randomly from a large area or designated land without any specific pattern. In a given land where soil test is to be performed, applying random sampling method will imply taking from several and different portions of the land. 

In the process, large number are expected and put together to form composite sample. A global position system is used to keep a record of soil nutrient data and the procedure can be used repeatedly for years over the same random points that are generated by the Global Position System (GPS). 

• DIAGONAL SAMPLING 

This method is used to collect representative soil samples from a field. The goal is to obtain a sample that accurately reflects the spatial variability of soil properties within the study area. Soil samples are collected from a series of pores along diagonal lines that cross the field or study area. 

The number of soil samples collected, as well as the distance between the diagonal lines can be adjusted based on the level of precision. 
The various sample units are combined to form a composite sample. 

• ZIDZAG SOIL SAMPLING 

Zigzag soil sampling is used in soil science research to collect representative soil samples from a larger area. The goal of this technique is to obtain a sample that accurately reflects the study area. 

In this method, soil samples are collected from a series of points along a zigzag pattern. This pattern is created by alternating between them and the number of soil samples collected can be adjusted based on the size of the study area and to the desired level of precision. 

TECHNIQUE FOR SAMPLING 

A hollow metal cylinder (soil corer) with a known weight is used to collect the soil samples from the filed of study. 

The weight or mass of each soil sample is calculated either by weighing the soil and corer together or taking the soil out into a beaker to determine its weight. 

For clay soil which have formed clumps or soil with clumps, it is being granded in the laboratory with mortar and pistil in order to get fine and small particle sizes of the soil. The soil is then oven dried or air dried to remove the moisture content. 

Afterwards, various soil analysis or test are being performed on the sample. 

Air drying is done when the sample is needed to determine nutrients and organic matter of the soil whilst oven drying is dine when analysing only the physical quantities of the soil and determing bulk density of soil.