The increased concentration of atmospheric CO2 is a mainly reason of the Earth warming. For the purpose of contributing to global environment, especially to decreasing theconcentration of atmospheric CO2, we are now researching and developing new technologies using soil microorganisms for reforestation in tropical and arid regions.

Nowadays the forest areas in the tropical region have been decreasing. One of the important problems in the tropical region is that Latosol, the infertile soil of which phosphate retention capacity is too high, spreads widely. In such an area the plant growth is very poor.

The microorganisms that we apply for this project are Arbuscular mycorrhizal (AM) fungi. AM fungi form mutualistic symbiosis with more than 80% of terrestrial plants.

Benefits of the symbiosis on host plants are:

　increased uptake of mineral nutrients, primarily P, which enhances growth

　increased uptake of water, which enhances drought tolerance

　enhanced resistance to certain diseases.

Our subjects are as follows;

1) Development of inoculation method of microorganisms for tropical reforestation (The target plats are Eucalyptus and Acacia.)

2) Evaluation of growth response by AM fungi under the soil condition similar with Latosol.

3) Field test (in Japan)

Our results this year are as follows;

1) AM fungi enhance the plant growth of Eucalyptus and Acacia under the soil condition similar with Latosol. To be concentrate, Eucalyptus treated with AM fungi are three times higher than those without AM fungi.

2) In the field test, AM fungi enhance the plant growth of Acacia. To be concentrate, the production-effect (the fresh weight / m2) of Acacia treated with AM fungi are three times more than those without AM fungi.