Fig.
4 Redundancy analysis (RDA) showing the relationships between enzyme
activity and enzyme stoichiometry (blue arrows) with soil
physicochemical properties and soil stoichiometry (red arrows) in
different land use patterns. (a):
The relationships in alfalfa
artificial grassland (AG). RDA analysis explained 90.80% of the total
variation in AG, RDA axis 1 and axis 2 explained 88.26% and 2.44% of
the variation respectively. TP and
NH4+-N had significant effects on
biological factors (p < 0.01), and the explanatory
degrees of biological factors were 75.4% and 7.4% respectively. (b):
The relationships in wheat-maize
rotation field (WM). RDA analysis explained 64.50% of the total
variation in WM, RDA axis 1 and axis 2 explained 34.72% and 29.49% of
the variation respectively. TP and WSA (2-1 mm) had significant effects
on biological factors (p < 0.01), and the explanatory
degrees of biological factors were 27.1% and 18.3% respectively. (c):
The relationships in native
grassland (PC). RDA analysis explained 93.80% of the total variation in
PC, RDA axis 1 and axis 2 explained 86.53% and 6.91% of the variation
respectively. NO3--N had significant
effects on biological factors (p < 0.01), and the
explanatory degree of biological factors was 56.00%. WSA: soil water
stable aggregate. pH: hydrogen ion concentration. EC: soil electrical
conductivity. TC: total carbon. TN: total nitrogen. TP: total
phosphorus. SOC: soil organic carbon.
NH4+-N: ammonium nitrogen.
NO3--N: nitrate nitrogen. AP: soil
available phosphorus. βG: β-1,4-glucosidase. NAG:
β-1,4-N-acetyl-glucosaminidase. LAP: L-leucine aminopeptidase. AP: acid
phosphatase. VL: vector length. VA: vector angle. C: carbon. N:
nitrogen. P: phosphorus.