As described in Kuncoro et al. (2014), disturbed sample of a
sandy loam volcanic ash soil (Table 1) taken from the ‘‘Takizawa’’
experimental field of Iwate University in northern Japan was
lightly sieved (4.76 mm) and set for 0.70 g g1 in water content
before it was mixed with rice husk, rice straw (cut into 2-cm
lengths), wood bark compost (well decomposed), sawdust, and
wood bark at 20% rate by volume.