The quality of carrier is a vital factor in determining microbial load and shelf life of
biofertilizers. Rice husk and cassava peels are abundant and practically of no
economic value in many developing countries and thus satisfy two important
requirements of biofertilizer-carrier materials. This study evaluated other
properties necessary to confirm their suitability for this purpose. Low moisture
content and bulk density, high porosity and good water absorption capacity of
both materials suggest adequate environmental conditions within them for the
growth and survival of inoculant organisms. Both carrier materials supported the
growth of the test organism, thus suggesting the presence of nutrients and
absence of toxicity. Rice husk showed potential for good shelf life. Promotion of
plant growth (p ≤ 0.5) by test organism was not diminished after six weeks of
immobilization in this carrier.