Gausal Azam

Improving the establishment of woody perennials in hostile soils by direct seeding

Although efforts to improve the reliability of ‘direct seeding’ have been attempted over the last few decades, the approach remains unproven as an alternative to transplanting, and many questions still need to be addressed before the direct seeding of woody perennials is ready for widespread adoption, especially in soils that have adverse physical and chemical properties.
This project addresses some of the key problems that make establishment by direct seeding of woody perennials unreliable, including: the inherent variability in native seeds, and the hostile soil and climatic conditions they face during the early stages of growth. 

In the first place, the relative performance of different woody perennials established by either direct seeding or transplanting will be evaluated in several locations in southern Australia. Variations in the plantation health will be evaluated in relation to soil properties examined in the field, laboratory and glasshouse. This combined approach to identify superior species will provide opportunities for greater success in direct seeding of native woody perennials.

Azam’s research falls into Program 3, New Woody Crops.

Objectives:

1. Survey and evaluate the relative performance of a number of mature woody species in forests that were direct-seeded or transplanted in southern Australia to characterize the soil conditions that may be responsible for differences in plant performance.
2. Explain the relative performance of selected species from the above field survey by exposing them to a range of limiting soil conditions in controlled laboratory and glasshouse environments. Sub-experiments will address the following objectives:

• Quantify the natural variability in axial root growth pressures that woody perennials can exert to identify species that can exert higher pressures and are likely to become established on inherently hard soils.
• Evaluate the range of soil water potentials and aeration conditions across which seeds of the selected woody perennials can germinate and survive.
• Quantify the variability in the responses of young woody perennials to the combined effects of limiting soil conditions such as salinity, poor aeration, low water potential and high soil strength.

For more information, email Azam.