ABSTRACT
The soil, the soil rhizophere, and the rhizoplane are marvelously complex and scientifically interesting ecosystems. The number of microorganisms found in these environments is impressive. Some ways in which soil microorganisms positively influence plant growth and development have been known and appreciated since the inception of soil microbiology in the late nineteenth and early twentieth centuries. Microbial fertilizers constitute the various living cultures that are said to contain strains of soil bacteria, fungi, actinomycetes, and algae, alone or in combination. Microbial products are generally applied by soil, seed, or seedling inoculation, with or without some carrier for the microorganisms–for example, peat, organic compost, or stickers. Currently marketed microbial products are likely to be ineffective because of problems in handling, storage, and applying the microorganisms to plants. The biological activators marketed at present are as suspect as the microbial fertilizers.
