2.2.3. Determination of the Soil Moisture Content (MCsoil)

In order to ensure an equal quantity of soil was used across all TMC boxes, measurements of soil moisture content (MCsoil) were used. The soil quantity decided on for all TMC boxes was based on the based on the oven-dry mass of the soil [g], and was dependent on the box's dimension. Each TMC box was filled to ensure a soil height of approximately 12 cm, to this end the oven-dry soil mass decided on for all TMC boxes amounted to 6000 g. The plastic TMC boxes were initially weighed in dry, empty state. Then, TMCs were over-filled with soil (i.e., >12 cm in height), with the box (including soil) weighed again to calculate the mass [g] of the soil component added to the box. Five MCsoil samples of 50 g each were then taken from multiple locations throughout the TMC box to ensure an average, but homogenously distributed MCsoil measurement was attained. Soil samples were weighed to the nearest 0.001 g, oven-dried at 103 ◦C for 24 h, and weighed again. MCsoil was calculated according to Equation (4) below. Once a representative MCsoil measurement was attained, a rearrangement of Equation (4) below was carried out to calculate the quantity of 'wet soil' (mw) required to be removed from the TMC box to attain 6000 g of oven-dry soil (m0):

$$\text{MC}\_{\text{soil}} = \left(\frac{\mathbf{m}\_{\text{W}} - \mathbf{m}\_{0}}{\mathbf{m}\_{0}}\right) \times 100\tag{4}$$

