Before plantation managers could start using eucalyptus root stock inoculated with ectomycorrhizal fungi, the project team had to develop cost-effective spore inoculation procedures for ectomycorrhizal fungi and identify site factors determining mycorrhizal responses and nutrient interactions in eucalypt plantations. Field trials were established at three sites in China (two in Guangdong Province and one in Yunnan) to test Australian mycorrhizal fungi in phosphorus-deficient soils. Molecular techniques were developed for confirming the presence of some introduced fungi on tree roots in the field.
Recommendations for macro- and micronutrient fertilisers for eucalypt plantations in China were also developed. Knowledge and skills were transferred through practical training and extension activities including mycorrhizal workshops in China. Chinese-language handouts and ACIAR research notes with recommended procedures for managing mycorrhizal plants in the nursery and in the field were produced and distributed.
During the project extension, scientists from CSIRO developed a website containing information on mycorrhizal fungi (see http://www.ffp.csiro.au/research/mycorrhiza/intro.html). As well, the ACIAR monographs Nutrient disorders in plantation eucalypts (first edition by B Dell, N Malajczuk & TS Grove issued as monograph 31 in 1995; revised edition by B Dell, N Malajczuk, D Xu & TS Grove issued as monograph 74 in 2001) are widely used by the industry.
This project resulted in about 25 per cent of total plantings now being inoculated in nurseries, and this should rapidly lead to the majority of private forest companies inoculating over 50 per cent of their clonal eucalypts. Inoculation with ectomycorrhizal fungi increases the sustainability of plantations by improved nutrient cycling and greater efficiency in the use of fertiliser by trees. In addition, it is estimated that tree productivity will be increased by a further 10 cubic metres/hectare/year MAI (mean annual increment) as a result of the improved fertiliser regime suggested by the project.
All new commercial eucalypt plantations are being supplied with fertiliser manufactured in China containing appropriate macronutrients (nitrogen, phosphorus, potassium and sulfur) and appropriate micronutrients such as boron and/or zinc. At least three companies are producing their own blend of compound fertiliser.
Several companies are routinely using foliar analysis to determine limiting nutrients for tree growth. Scientists in China are now able to provide start-up inoculum to forestry companies and the Forestry Bureaus. They have also extended the applied research from eucalypts to agricultural crops such as banana, litchi, longan, cassava and to ornamental crops such as flowering plants. Forest technicians are providing advice on mycorrhizal technology in the regions to nursery managers.