Operational Suckering Trial


To assess the environmental impact of land application of the sludge without incorporation in terms of soil quality and surface water quality.


The SLP Operational Suckering Trial began in 2000 Northeast of the Winter Applied Slope Trial. The trial included:

  • Sludge spreading at rates of 30 and 60 t/ha
  • Baseline height and diameters were determined for 100 suckers in each of the control and sludge amended areas. 
  • Post-application height and diameter measurements were determined in 2001 to 2007 and again in 2010. 
  • Soil and Water sampling and analysis were conducted on control and sludge affected areas.

Results and Conclusions

  • The data indicate that sludge application resulted in a substantial change particularly in diameter and the resultant stemwood volume. 
  • The projections that were applied to the data indicate that by 2025 when the trees are 25 years old the sludge applied treatments will have significantly more stemwood volume compared to the control.
Area Application Rate (t/ha) Age Shift Growth Multiplier
 Height Diam Height  Diam 
SLP Operational
Suckering Trial
60 2.9 12.7 1.13 2.03