Soil sample collection for soil test (V shape method) HD

Soil sample collection for soil test by using "V" shape method. Soil testing is an essential component of soil resource management. Each sample collected must be a true representative of the area being sampled. Utility of the results obtained from the laboratory analysis depends on the sampling precision. Hence, collection of large number of samples is advisable so that sample of desired size can be obtained by sub-sampling. In general, sampling is done at the rate of ten sample for one acre area. For soil survey work, samples are collected from a soil profile representative to the soil of the surrounding area. Points to be remembered- Sampling at several locations in a zig-zag pattern ensures homogeneity. Fields, which are similar in appearance, production and past-management practices, can be grouped into a single sampling unit. Collect separate samples from fields that differ in colour, slope, drainage, past management practices like liming, gypsum application, fertilization, cropping system etc. Avoid sampling in dead furrows, wet spots, areas near main bund, trees, manure heaps and irrigation channels. For shallow rooted crops, collect samples up to 15 cm depth. For deep rooted crops, collect samples up to 20-22 cm depth. Always collect the soil sample in presence of the farm owner who knows the farm better. Materials required- 1. Spade or auger 2. Plastic tray or polythene sheet 3. Scale 4. Sampling bags Procedure- 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, crop to be grown in the next season, date of collection etc.