3. Results
3.1. Effects of different land use patterns on soil physical and chemical properties
Soil physical properties were significantly affected by land use patterns (Table 3). Compared with PC, AG and WM significantly reduced soil BD and increased the contents of WSA (> 0.25 mm). The WSA contents of AG were mainly concentrated in > 0.5 mm, accounting for 69.51%, 74.20%, and 73.58% of the total WSA content in 0-20, 20-40, and 40-60 cm soil layers, respectively. The WSA contents of WM were mainly concentrated in 2-0.25 mm and accounted for 63.68%, 60.88%, and 66.25% of the total WSA content in 0-20, 20-40, and 40-60 cm soil layers, respectively. The WSA contents of PC were concentrated in > 2 mm and < 0.25 mm.
Soil pH and EC increased with soil depth (Table 4). Compared with PC, AG and WM increased soil pH in 0-20 cm layer and decreased soil pH in 40-60 cm layer. AG increased EC in 0-20 cm soil layer and decreased EC in 40-60 cm soil layer, while EC in WM was higher than that in other land use patterns. The contents of SOC, NH4+-N, NO3--N, and AP decreased with soil depth, and these contents of AG and WM were significantly higher than that of PC. Compared with WM, AG was more helpful to increase the contents of NH4+-N and NO3--N in soil. NH4+-N contents in 20-40 and 40-60 cm soil layers and NO3--N contents in 0-20 cm soil layer of AG were significantly higher than those of WM and increased by 9.58%, 13.36%, and 15.06% respectively.