1. Effects of N and S addition on forest soils – the challenge experiment
Craig Neufeld
(M.Sc. Candidate)

2. Objectives
Determine the effects of N and S deposition on the forest ecosystem and their role in soil acidification

3. The Experiment Site located ~ 100 km SE of Ft McMurray
Addition of N and S in a 2x2 factorial design
N: 30 kg/ha N as NH4NO3
S: 30 kg/ha S as Na2SO4

4. Soil Solution
Lysimeters
2 / plot / depth
Depth
10 cm and 40 cm

5. Soil Chemistry Exchangeable ions – NH4Cl extraction
NH4+ and NO3- – KCl extraction
Soluble Chemistry – Saturated Paste

6. [NH4+] mmol-N/m2
N and S application date

7. [NO3-] mmol-N/m2

8. [SO42-] mmol-S/m2

9. [Na] mmol/m2

10. Base Cations

11. Soluble Base Cations

12. Soluble Ca:Al ratio

13. Exchangeable Base Cations - 2008

14. Summary – N effects
-Addition of NH4NO3 resulted in increase leaching of NH4 and NO3
-time of leaching dependent on form of N
-N addition resulted in slight, but not sig. increase in K, Ca, and Mg leaching in macro pores
-N addition resulted in slight, but not sig, decrease in the Na, K, Ca, and Mg concentrations in the micropores
-N addition resulted in the increase in NH4+ adsorbed to soil surface
-N addition resulted in slight, but not sig, decrease in the Na, K, Ca, and Mg adsorbed to soil surface

15. Summary – S effects
-Na2SO4 addition resulted in an increase in Na, SO42-, Ca, and Mg leaching
-Na2SO4 addition resulted in an increase in the Na, Ca, and Mg concentrations in the micropores
-Na2SO4 addition resulted in the slight, but not sig, increase in the amount of Na adsorbed to soil surface
-Na2SO4 addition resulted in the slight, but not sig, decrease in the K, Ca, and Mg amounts adsorbed to soil surface

16. Aspen Growth Increment 2006 to 2008

17. Continuing work Complete analysis of soil leachate and soil chemistry
Complete analysis of foliar and litterfall chemistry
Complete vegetation growth and species composition analysis

18. Acknowledgements Dr. Scott Chang Dennis
NOx-SO2 Management Working Group
Boajing
Steve and Kangho
Tom

19. Questions??
Craig Neufeld
(M.Sc. Candidate)