In our study area, a total number of 126 soil samples were collected by means of a screw type auger of which 54 samples were from Terai and 72 samples were from Dooars region. Each sample was gathered by mixing five presamples collected from the corners of an imaginary square of ten metres side and from its diagonal bisector. About five hundred grams of soil samples were brought to laboratory in airtight zipper bags for downstream analysis. Soil samplings were performed early in the morning before application of fertilizers. Topsoil (0-15 cm) and sub soil (15-30 cm) were dug under the canopies of tea bushes.
Preparation of Soil Samples for Analysis
The collected soil samples were completely air dried. Debris from the samples like roots, pebbles etc were removed by hand. The clean air dried samples were passed through 2mm sieve and crushed with mortar and pestle. For organic carbon determination, the samples were further passed through final mesh sieve (0.5mm).