Fig. 2 Effects of different land use patterns on βG (a), NAG (b), LAP (c), ACP (d), enzyme C: N ratio (e), enzyme C: P ratio (f), enzyme N: P ratio (g), vector length (h) and vector angle (i). Different letters indicate significant differences among different land use patterns in the same soil layer (p< 0.05). βG: β-1,4-glucosidase. NAG: β-1,4-N-acetyl-glucosaminidase. LAP: L-leucine aminopeptidase. ACP: acid phosphatase. C: carbon. N: nitrogen. P: phosphorus. AG: alfalfa artificial grassland. WM: wheat-maize rotation field. PC: native grassland.