he soil balls exerted almost neutral pH (pH 7.3) which caused up to a fourfold increased hardness of the soil ball. Moreover, the 0.75 % of hardener in the soil ball also improved the water quality due to a si
he soil balls exerted almost neutral pH(pH 7.3) which caused up to a fourfold increased hardness ofthe soil ball. Moreover, the 0.75 % of hardener in the soil ballalso improved the water quality due to a si