Seeding Trial in the Mid Hunter
Trialling mine site rehabilitation techniques on degraded Spotted Gum Ironbark Forest
Collaborations - LP038-010
The issue
Land encompassed by the Lake Liddell recreation area, roughly midway between Muswellbrook and Singleton has been subject to clearing and heavy grazing since the time of European colonisation. In that time the soil's O and A horizons have been lost or heavily modified resulting in compacted soils, an absent shrub layer and depauperate understory. The overstory mainly consists of mature Spotted Gum (Corymbia maculata) and Ironbark (Eucalyptus crebra) with Bulloke (Allocasuarina leumanii) in the gullies, salinity is present with the occasional scald. With the exception of suckering Bulloke regeneration is mostly absent.
The solution
Nearby coal mines have been rehabilitating sites by incorporating composted material into the top 100mm and broadcast seeding into area. It was decided by the reserve management committee to trial that methodology with a mix of mid story species.
An area of roughly 1.3 hectares was fenced off, composted mulch was spread in three strips, incorporated into the topsoil, then seeds hand broadcast over the top.
The impact
It is currently too early to tell whether this methodology is a viable technique for previously grazed pastures, however soil moisture and ongoing rainfall over 2021-23 should provide ideal conditions for seed germination. Germination will be monitored over spring-summer 2022-23 as a "proof of concept" with ongoing monitoring over subsequent years to examine the viability of use of this technique.
If successful this will add another method to undertake wide scale rehabilitation of degraded lands.
Key facts
- Large scale rehabilitation of previously grazed land presents numerous difficulties
- While planting can be effective it is costly and time and labour intensive
- Techniques used in mine site rehabilitation might be applicable to rehabilitation of previously grazed lands
- Midstory shrub species were sown