3.1 Soil properties
After forest conversion, soil BD was higher and SWC was lower in the plantations compared with the forest (Fig. 1a). The SOC and DOC contents were 83% and 39% lower, respectively (Fig. 1b, d). A similar decreasing trend was found for TN, NH4+and NO3- contents (except Berry; Fig. 1b, d). Consequently, the soil C:N ratio (C/N) strongly dropped by 11.9 (Fig. 1b). However, the highest TP, TK and AP, AK contents were observed under Peach. Compared to the other three plantations, TP, TK and AP, AK in Peach was 26%, 12%, 88% and 43% higher, respectively (Fig. 1b, d). Compared with the forest, Ca2+ content in plantations was reduced by 43%.
Soil enzyme activities decreased after conversion, including SC, ACPT, ACP, GLS, ACP and ALP (Fig. 1c). For instance, SC, ACPT and GLS activities declined up to 40%, 64% and 67%, respectively (Fig. 1c). Similarly, soil phosphatase activities were lower in the plantations, and ACP and ALP activities declined by approximately 93% and 59%, respectively (Fig. 1c). Likewise, with the exception of Berry (Fig.1c), the UR activities were lower in the plantation than in the forest (Fig. 1c).