A. Sivapalan, W.C. Morgan and P.R. Franz

Australian Journal of Experimental Agriculture 34:541-548. 1994

This study examined whether or not the beneficial fungi Acremonium butyri, Chaetomium globosum, Gliocladium roseum, Trichoderma hamatum, and Zygorrhynchus moelleri can be managed or manipulated on farms to increase crop production. Each of the five species was tested separately for its ability to promote growth of tomato plants. Isolates of the fungi were used to inoculate soilless mature compost. Four-week-old tomato seedlings were transplanted into the compost three days after inoculation and arranged in a randomized complete block design consisting of seven replicates with seven treatments [each of the five fungi indicated above, uninoculated compost, and uninoculated compost plus NPK (5:8:4 at 1 ton per hectare)]. Growth of plants, as well as microbial populations, were monitored weekly. Microbial populations were also measured in pots without tomato plants to assess the affect of plant roots on the soil system.
Researchers found that T. hamatum and Z. moelleri increased growth of tomato plants in soilless compost over and above growth that could be attributed to fertilizer additions by nearly 10 percent, and that the populations of these fungi remained constant over the course of the experiment. The study showed that A. butryi, C. globosum and G. roseum also enhanced growth of tomato plants, but their numbers declined over time. The investigators also looked at the effect of fungal inoculation on the populations of other fungi that were naturally present. Aspergillus fumigatus was the dominant uninoculated fungal species in all treatments at the beginning of the experiment, but its numbers were reduced significantly by T. hamatum, G. roseum (with plants), and Z. moelleri (without plants). The inoculated fungi reduced populations of other fungi as well, including species of Fusarium, Mucor, and Penicillium. There was no inhibition observed on populations of bacteria or actinomycetes. Higher numbers of microorganisms in pots with plants as compared to pots without plants supports the general observation that substances released to the soil by plant roots stimulate growth of microorganisms. The researchers noted that T. hamatum and Z. moelleri have certain characteristics that make them adaptable to a wide range of environmental conditions. Such qualities, in this reviewer's opinion, suggest possible uses by farmers and ranchers as a means to reduce certain diseases or to promote plant growth. Further investigation along these lines is clearly warranted.

For more information: A. Sivapalan, Dept. of Agriculture, Institute for Horticultural Development, 621 Burwood Highway, Knoxfield, Victoria 3176, Australia.

(DEC.544)

Contributed by David Chaney