AMF contribution
Compared to no AMF inoculation, AMF inoculation significantly increased
plant net photosynthetic rate (p < 0.001, Table 1), and
significant differences in plant net photosynthetic rates among the
different AMF diversity treatments were observed (p <
0.001, Table 1, Figure 3a). The net photosynthetic rate under high AMF
diversity was consistently higher than that under low AMF diversity,
except under microplastic and saline-alkali conditions, where the
differences were not significant. Under control, antibiotic, pesticide,
drought, and multiple GCFs, the net photosynthetic rate with high AMF
diversity was higher than that with any single AMF species. Compared to
single GCF treatments, multiple GCFs significantly reduced the net
photosynthetic rate of plants inoculated with single AMF species
(p < 0.001) but had no impact under mixed AMF or no AMF
inoculation treatments. AMF inoculation also significantly increased
aboveground biomass compared to no AMF inoculation (p <
0.001, Table 1), and significant main effect of AMF diversity on
aboveground biomass was detected (p < 0.001, Table 1,
Figure 3b). Within the same GCF treatment, aboveground biomass under
high AMF diversity was much higher than low AMF diversity and no AMF
inoculation except under microplastic and drought treatments. GCF
numbers significantly affected aboveground biomass (p <
0.001, Table 1), multiple GCFs significantly reduced aboveground biomass
compared to single GCF treatments.
The effect of AMF diversity on soil functions was not always
significant. Significant differences in soil N2O
emissions between AMF inoculated and non-inoculated treatments were
observed (p < 0.01, Table 1). Under multiple GCFs, low
AMF diversity treatment increased the emissions of N2O,
but high AMF diversity did not affect it. A significant main effect of
the number of GCFs on N2O emissions was detected
(p < 0.001, Table 1). Under the inoculation of a single
AMF, multiple GCFs significantly increased N2O emissions
compared to single GCF and the control (p < 0.01,
Figure 4a). AMF diversity and the numbers of GCF did not interactively
affect CH4 emissions (p > 0.05,
Table 1). Both AMF inoculation (p < 0.01) and GCF
numbers (p < 0.001) significantly affected soil NO₃⁻-N
content (Table 1, Figure 4c), but the effect of AMF diversity was not
significant (p = 0.121). The effect of GCF numbers on soil NH₄⁺-N
content was highly significant (p < 0.001, Table 1).
When AMF was inoculated, NH₄⁺-N content decreased with increasing GCF
numbers (Figure 4d). AMF inoculation significantly affected βG activity
(p < 0.001, Table 1). AMF inoculation significantly
reduced βG activity under control, antibiotic, and pesticide treatments
(Figure 4e). The effect of GCF numbers was also significant (p < 0.05, Table 1). Soil CBH activity ranged from 6.84 ± 0.90,
with lower activity of 2.54 ± 1.37 observed under antibiotic pollution
with no AMF inoculation. Both AMF inoculation (p <
0.001) and GCF numbers (p < 0.01) significantly
affected CBH activity, with AMF inoculation significantly increasing CBH
activity under antibiotic, microplastic, pesticide pollution, and
drought conditions (Figure 4f). No significant difference in CBH
activity between low and high AMF diversity was observed. For low AMF
diversity, CBH activity under multiple GCFs was significantly higher
than under single GCF or no GCF treatments (p < 0.01).
AMF inoculation showed a significant effect on NAG activity (p < 0.01, Table 1). AMF inoculation significantly reduced NAG
activity under nitrogen addition but increased it under antibiotic,
microplastic and drought conditions compared to no AMF inoculation
(Figure 4g). AMF diversity, GCF numbers, and their interaction
significantly affected ALP activity (all p < 0.01,
Table 1). For high AMF diversity, ALP activity under no GCF was
significantly higher than that under single and multiple GCF treatments
(p < 0.001, Figure 4h). For low AMF diversity, ALP
activity under multiple GCFs was significantly higher than that under no
GCF and single GCF treatments (p < 0.001, Figure 4h).
Compared to the effects of a single AMF species inoculation on ecosystem
multifunctionality, and particularly plant growth, the results showed
that high AMF diversity exhibited notable complementarity effect, where
the AMF mixture exhibited a greater performance than any of the single
inoculated AMF, under no GCF, multiple GCFs, and some single GCF
treatments. However, such advantages and complementarity effects were
not evident for soil functions.