Mid-succession Fertilization Study
Fertilization treatments in the mid-succession site also supported
significantly different mixtures of Frankia clades (Table 3) (LR
P < 0.0001, pseudo-R2 = 0.13) and subclades (Table 4) (LR P
< 0.0001, pseudo-R2 = 0.14). Control soils yielded a
relatively even mixture of sequences belonging to the AT clade and
sub-clades unique to soil. Proportional representation of AT clade
sequences was significantly higher in soils fertilized for 12 years with
N (84% of clones, P < 0.0001) or five years with P (51% of
clones, P = 0.0026) than in unfertilized control soils (23% of clones).
N-fertilized soil also contained notably lower diversity than the other
two treatments, yielding less than half of the sub-clade richness as
control soils, while P-fertilized soil yielded representatives of every
sub-clade present in control soils, albeit at different relative
proportions (Figure 2, Table 3, Table 4) due primarily to the dominance
of AT clade sequences in P-fertilized soil.