Effects of Moso Bamboo Expansion on Soil Carbon, Nitrogen, Phosphorus and Ecological Stoichiometry Characteristics of Forest in Mufu Mountain Area

To study the effect of moso bamboo expansion on soil carbon(C), nitrogen(N) and phosphorus(P) into different stands, we selected 2 continuous interfaces from a moso bamboo stand to its surrounding Chinese fir forest and broad-leaved forest in Mufu mountain area as the research objects. The contents of SOC, TN, TP, NO₃⁻−N, NH₄⁺−N and their ecological stoichiometric ratios in different forest types were analyzed. The results showed that the contents of SOC, TN, TP and NH₄⁺ −N decreased gradually with the increase of soil depth under the 2 expansion patterns, except the content of NO₃⁻−N changed irregularly. During the expansion of moso bamboo to Chinese fir forest, there was no significant difference in SOC, TN and TP contents in the same soil layer. However, during the expansion of bamboo to broad-leaved forest, the SOC and TN contents in 0–10 cm soil layer of bamboo forest decreased by 27.71 % and 30.45 % compared to those in broad-leaved forest and d⁻ecrease 36.67 % and 31.11 % compared to bamboo broad-leaved mixed forest, while there was no significant difference in 10–20 cm and 20–30 cm soil layers. Moso bamboo expansion had no significant effect on TP content in each soil layer of Chinese fir forest and broad-leaved forest. The expansion of moso bamboo to Chinese fir forest increased NH₄⁺−N content both in 0–10 cm and 20–30 cm soil layers, and the expansion to broad-leaved forest increased NH₄⁺−N content in 10–20 cm soil layer and NO₃⁻−N content in 20–30 cm soil layer. There was no significant effect of moso bamboo expansion to Chinese fir forest on soil C/N, C/P and N/P, while the expansion to broad-leaved forest resulted in a significant decrease in N/P in 0–10 cm soil layer and a significant increase in C/N in 10–20 cm soil layer. In conclusion, the expansion of moso bamboo to Chinese fir forest had no significant effect on the SOC, TN and TP contents, but increased the content of NH₄⁺−N in surface and deep soil layer. However, the expansion of moso bamboo to broadleaved forest resulted in a significant decrease in SOC and TN contents in surface soil, and a significant increase in NH₄⁺−N contents in middle soil and NO₃⁻−N content in deep soil layer.