3.2. Effects of different land use patterns on soil stoichiometry
The total carbon contents of each soil layer were WM > AG > PC (Fig. 1). The total nitrogen contents decreased with the deepening of the soil layer, and the total nitrogen contents of each soil layer were AG > WM > PC, and the differences were significant. The total phosphorus contents of AG and WM were significantly higher than PC and increased by 47.57% and 54.60% respectively in 0-20cm soil layer, while they were not significant in 20-40 and 40-60 cm soil layer.
The soil C:N ratios in 0-20 and 40-60 cm soil layers were WM > PC > AG, while those in 20-40 cm soil layer were PC > WM > AG (Fig. 1). The soil C:P ratios of each land use pattern were not significant in 0-20 cm soil layer, while they showed WM > AG > PC in 20-40 and 40-60 cm soil layers. The soil N:P ratios of AG were significantly higher than those of WM and PC in each soil layer. The mean soil stoichiometric ratios of AG, WM, and PC were 31.32: 1.74: 1, 34.05: 1.46: 1, and 26.58: 1.14: 1, respectively.
3.3. Effects of different land use patterns on soil enzyme activity and enzyme stoichiometry
The enzyme activities of βG and NAG decreased with the deepening of the soil layer (Fig. 2). In 0-20 and 20-40 cm soil layer, the βG enzyme activities of AG and WM were significantly higher than those of PC. The NAG enzyme activities of AG in all soil layers were higher than that of WM and PC. ACP enzyme activities in 0-20 and 20-40 cm soil layers were AG > WM > PC, but in 40-60 cm soil layer, WM were significantly higher than other land use patterns. The enzyme activities of LAP in each soil layer were WM > AG > PC, and increased with the deepening of the soil layer.
The enzyme C: N ratios of different land use patterns in different soil layers were greater than 1:1 (Fig. 2). The enzyme C: N ratios of PC were lower than those of other land use patterns in 0-20 and 20-40 cm soil layers, and the same was true for AG in 40-60 cm soil layer. The enzyme N:P ratios were less than 1:1. The enzyme N:P ratios of WM in 0-20 cm soil layer and AG in 40-60cm soil layer were higher than those of other land use patterns. The enzyme C:P ratios were less than 1:1 except for the WM in 20-40 cm soil layer. The enzyme C:P ratios were WM > AG > PC in 0-20 and 20-40 cm soil layers and AG > PC > WM in 40-60 cm soil layer. The mean enzyme stoichiometric ratios of AG, WM, and PC were 0.96: 0.76: 1, 0.94: 0.74: 1, and 0.86: 0.73: 1, respectively. In 0-20 and 20-40 cm soil layers, the VL values of PC were significantly lower than those of other land use types. The VA of each land use pattern was more than 45°.