Municipal solid waste compost can provide a rich organic nutrient source and soil conditioner for agricultural and horticultural applications. To comparison three techniques of estimating phytotoxicity of municipal solid waste compost, the effect of different aqueous extracts obtained from municipal solid waste compost and different mixing ratios of sand-compost on the seed germination and early seedling growth of cress (Lepidium sativum L.), isabgol (Plantago ovata Forsk) and cumin (Cuminum cyminum L.) were studied by bioassay. The aqueous extracts of compost strongly inhibit plant germination and root growth of cress. The germination index values obtained for compost extracts were low, when compared with that of the control. Latent toxicity of compost for different plant species seemed not to be severe. However, when cress, isabgol and cumin were germinated in a sand-compost mixture (25:75 and 50:50), germination of cress was completely inhabited, with a sever reduction of the isabgol and cumin root growth. To avoid negative effects of compost on crop, routine germination bioassay should be included in education program for farmers. This showed enhance marketing and consumer acceptance of municipal solid waste composts.
