Thorpe AS1, Callaway RM. Biogeographic differences in the effects of Centaurea stoebeand catechin on the soil nitrogen cycle. Biological Invasions.

1Corresponding author: Andrea S. Thorpe, Institute for Applied Ecology,

Table OR4. Summary of one-way ANOVA of effect of treatment (catechin, C. stoebe soil, or grass soil) ammonification and nitrification rates in soils from Montana and Romania, measured through 15N pool dilution. P<0.05 are in bold.

Dependent variable / Factor / df / MS / F / P
Montana
Week 5
Ammonification / Treatment / 2 / 9.852 / 0.176 / 0.845
Error / 4 / 55.981
Nitrification / Treatment / 2 / 1033.407 / 4.091 / 0.047
Error / 11 / 252.579
Week 9
Ammonification / Treatment / 2 / 3.140 / 0.968 / 0.413
Error / 10 / 3.244
Nitrification / Treatment / 2 / 18.714 / 7.17 / 0.510
Error / 11 / 26.112
Week 12
Ammonification / Treatment / 2 / 0.181 / 0.909 / 0.429
Error / 12 / 0.199
Nitrification / Treatment / 2 / 5.661 / 0.275 / 0.765
Error / 11 / 20.614
Romania
Week 5
Ammonification / Treatment / 2 / 5.579 / 8.819 / 0.023
Error / 5 / 0.633
Nitrification / Treatment / 2 / 51.507 / 1.338 / 0.302
Error / 11 / 38.492
Week 9
Ammonification / Treatment / 2 / 3.566 / 1.426 / 0.281
Error / 11 / 2.500
Nitrification / Treatment / 2 / 156.993 / 1.964 / 0.191
Error / 10 / 79.948
Week 12
Ammonification / Treatment / 2 / 0.158 / 0.459 / 0.643
Error / 12 / 0.344
Nitrification / Treatment / 2 / 36.591 / 1.767 / 0.213
Error / 12 / 20.708

Tests were performed using the Type three sums of squares from SPSS version 13 (SPSS Inc., Chicago, IL, USA).