2.3 Biomass sampling and analysis
A total of 10 sampling points was randomly selected at the waste dump and an area of 1 m2 at each point was marked for vegetation sampling. We used the harvest method to estimate shoot and root biomass. Soil particles attached to roots were separated by soaking and washing with a fine jet of water with ultrasonicator. During soil sampling, rooting depth was measured (i.e., depth of root penetration). Shoot and root biomass was separated and oven-dried at 65oC for 48 hours to measure the weight of the dry biomass. Biomass samples were finely grounded and a sieved (<1mm) to determine the total carbon (C) and nitrogen (N) using an elemental analyzer (Euro EA 3000 Eurovactor, Italy). Dry mulch accumulated on the surface layer was collected by using quadrate (size: 30 cm × 30 cm), from the same location where soil and vegetation samples were collected.