How can I take samples from the farm soil to do analysis?
- Divide the field into different homogenous units based on the visual observation and farmer’s experience.
- Remove the surface litter at the sampling spot.
- Drive the auger to a plough depth of 15 cm and draw the soil sample.
- Collect at least 10 to 15 samples from each sampling unit and place in a bucket or tray.
- If auger is not available, make a ‘V’ shaped cut to a depth of 15 cm in the sampling spot using spade.
- Remove thick slices of soil from top to bottom of exposed face of the ‘V’ shaped cut and place in a clean container.
- Mix the samples thoroughly and remove foreign materials like roots, stones, pebbles and gravels.
- Reduce the bulk to about half to one kilogram by quartering or compartmentalization.
- Quartering is done by dividing the thoroughly mixed sample into four equal parts. The two opposite quarters are discarded and the remaining two quarters are remixed and the process repeated until the desired sample size is obtained.
- Compartmentalization is done by uniformly spreading the soil over a clean hard surface and dividing into smaller compartments by drawing lines along and across the length and breadth. From each compartment a pinch of soil is collected. This process is repeated till the desired quantity of sample is obtained.
- Collect the sample in a clean cloth or polythene bag.
- Label the bag with information like name of the farmer, location of the farm, survey number, previous crop grown, present crop, crop to be grown in the next season, date of collection, name of the sampler etc.
Collection of Soil Samples from a Profile
- After the profile has been exposed, clean one face of the pit carefully with a spade and note the succession and depth of each horizon.
- Prick the surface with a knife or edge of the spade to show up structure, color and compactness.
- Collect samples starting from the bottom most horizon first by holding a large basin at the bottom limit of the horizon while the soil above is loosened by a khurpi.
- Mix the sample and transfer to a polythene or cloth bag and label it.
Guidelines for Sampling Depth
Soil Sampling Depth
Grasses and grasslands
Rice, finger millet, groundnut, pearl millet, small millets etc.(shallow rooted crops)
Cotton, sugarcane, banana, tapioca, vegetables etc. (deep rooted crops)
Perennial crops, plantations and orchard crops
Three soil samples at 12, 24 and 36 inches
Three soil samples at 30, 60 and 90 cm