SOIL AND PLANT ANALYSIS (1+1)

Collection of soil samples from the field

• Normally each field may be treated as a sampling unit. But two or more fields, which are similar in appearance, production and past-management practices may be grouped together into a single sampling unit.


• Samples should be collected separately from areas, which differ in soil colour or past-management practices such as liming, fertilization, cropping pattern etc.


• During collection of soil, dead furrows, old manure or lime piles, wet spots, areas near trees, manure pits, compost pits, near field bunds and irrigation channels must be avoided.


• The sampling should be done in a zigzag pattern across the field to get homogeneity. A wise collecting agent is one who collects samples in the presence of the owner or cultivator of the land who is the best judge in deciding which area of his farm should be sampled separately.


• Scrap away the surface litter and insert the sampling auger to plough depth (15 cm).


• Take at least 15 samples randomly distributed over each area and put them in a clean bucket.


• If a sampling auger is not available make a ‘V’ or ‘U’ shaped cut to a depth of 15 cm or to a required depth using a spade and remove 1.0 to 1.5 cm thick slice of soil from top to bottom of the exposed face of the ‘V’ or ‘U’ shaped cut and put in a clean bucket or basin and in similar manner collect the soil sample from all the spots.


• Thoroughly mix the soil samples taken from 15 or more spots of each area. Remove foreign bodies such as plant roots, stubbles, leaves, glass pieces, pebbles, stones or gravels. By quartering technique, discard all but ½ to 1 kg soil.


• Quartering technique is done by dividing the thoroughly mixed soil into four equal parts and discarding two opposite quarters.


• Remix the remaining two quarters and again divide into four equal parts and reject the opposite two.


• Repeat this procedure until about ½ to 1 kg of soil is left. Instead of quartering, compartmentalization method can be followed.


• For this, spread the soil on a clean hard surface and mark lines from both the sides and create number of compartments.


• Take a little quantity of soil from each compartment and put into a clean container.


• Repeat the process of collection until the required quantity is collected.


• Store the soil in a clean cloth bag or container with proper lableling for further analysis.