B). Solid media culture or aggregate system
The media material selected must be flexible, friable, with water and air holding capacity and can be drained easily. In addition, it must be free of toxic substances, pests, disease causing microorganisms, nematodes, etc. The medium used must be thoroughly sterilized before use. The following techniques involving inert solid media can be practiced using locally available materials. The various salient finding in aggregate system are given in Table 7.