Figure 4.

The response of barley (shoot dry weight, dwt; mean ± se; N = 8 per treatment) grown under greenhouse conditions to the addition of biochar created from four different feedstocks: Ulex sp., Juncus sp., olive stones and hardwood, and wood chips. Biochar was added to pots at three rates (0 g, 2 g, or 4 g per pot) and was added in two forms, powdered (BCP) and ‘sieved’ (BCS), with grains between 3–7 mm. These biochar treatments were combined with the addition of HexaFrass at two rates (0 g and 3 g per pot) to produce ten treatments in total for each biochar.