Agrispon: microbiological and elemental analysis and evaluation of its effect on the growth of wheat, barley, field beans, and corn

The "soil conditioner" Agrispon has been sold privately to Canadian farmers but it is not licensed for sale. The manufacturers claim that Agrispon will promote crop yields by hastening germination, increasing drought resistance, fixing atmospheric N 2 , and generally stimulating plant growth. No scientifically valid literature exists to substantiate these claims so experiments were undertaken to determine the elemental and microbiological constituents of Agrispon in order to interpret its effect on plant growth in a greenhouse study. Agrispon contained insufficient nutrients to substitute for recommended fertilizer additions. It contained only 10 times more bacteria than Lethbridge tap water and none of the bacteria isolated were capable of fixing atmospheric N 2 . Nor were any of the bacterial isolates plant or human pathogens. Agrispon had surprisingly low numbers of fungi, approximately 10/mL, and no algae were isolated. The fungal isolates were tentatively identified as members of the ubiquitous Penicillium spp., Fusarium spp., and species of the mycelia sterilia. The addition of Agrispon as seed-applied, pre-plant-incorporated, a combination of these two, or post-emergence product had no consistent effect on germination and no effect on any parameter of plant yield of wheat, barley, field beans, and corn relative to the unfertilized control. This was not surprising since elemental and microbiological analysis confirmed that Agrispon contained insufficient nutrients and no appropriate microorganisms that could conceivably benefit plant growth. Agrispon cannot be recommended for licensing in Canada or for private import by producers. Key words: Triticum aestivum, Hordeum vulgare, Phaseolus vulgaris, Zea mays, N 2 -fixing bacteria