Research on the utilization of arbuscular mycorrhizal fungi for the establishment of forest tree seedlings

Survey and Investigation of Arbuscular Mycorrhizal Fungi (AM) was undertaken from soil and rhizosphere samples collected from the experimental plots at Maeklong Watershed Research Station, Thong Pha Phum, Kanchanaburi Province. The results showed that the most common founded AM strains belonged to the species Sclerocystis clavispora, Glomus albidum, Glomus monosporus, Slerocystis rubiformis and Acaulospora scrobiculata. Evaluation on the occurrence and distribution of AM indicated variation of intensity/frequency of AM strains associated with soils and rhizospheres of different vegetation types and climatic seasons. The intensities of AM occurrence and distribution in each seasonal period were estimated at 20 percent with maximum 6 strains in December, 25 percent with maximum 13 strains in March, 29 percent with maximum 18 strains in June and 24 percent with maximum 10 strains in September. The intensities of AM occurrence in each experimental plot were 21 percent in natural forest, 29 percent in grass land, 26 percent in plantation of teak mixed with Gmelina arborea and 24 percent in young teak plantation The highest number of AM strains found in each experimental plot were 15 strains in grass land, 13 strains in mixed plantation of teak and Gmelina arborea, 11 strains in young teak plantation and 9 strains in natural forest. During 1996-2001 the research was carried out in the laboratory, glasshouse and field trials at TISTR-Lamtakong Research Station. Pak Chong District, Nakhon Ratchasima Province. Multiplication of AM strains is effective using fibrous root-monocotyl plants such as Panicum maximum cv. Hamil grass, Guinea grass, maize and sorghum. The suitable planting materials were mixed sandy soil with low pH and phosphate content. Coconut husk and charcoal powder are suitable carrier and binder materials for inoculant. Testings for the efficiency of AM with seedlings of tree species, namely Acacia mangium, Azadirachta indica and Pterocarpus macrocarpus showed that seedlings with AM inoculation had better growth (height and dry matter yields) than uninoculated plants. Field trial testing of Acacia mangium, Azadirachta indica and Pterocarpus macrocarpus showed that most of the transplanted plants, which were inoculated with AM strains had better growth and higher survival percentages than the uninoculated plants. The result from the multiplication and efficiency testing of AM has let to the production of AM inoculants in form of powder, tablet, capsule and plug for the purpose of utilization as biofertilizer.