Effects of Afforestation Densities and Tending Measures on the Growth and Soil Enzyme Activity of Cunninghamia lanceolata Plantation

In order to study the effects of different afforestation densities and tending measures on the growth and soil enzyme activity of Cunninghamia lanceolata young forest, an L₉（3⁴） orthogonal experimental design was employed to investigate the effects of different afforestation densities(1665 plants·hm^-2,1995 plants·hm^-2 and 2505 plants·hm^-2) and young forest tending measures（hole tending, full split, hole tending + full split） on the growth and soil enzyme activity of C.lanceolata young forest after 2 years of planting.Two-year-old C.lanceolata seedlings were used for ecological afforestation treatments, and a traditional afforestation method of one-year-old C.lanceolata seedlings was included as control（CK）.The results showed that（1） Different afforestation methods had no significant effect on the survival rate of C.lanceolata plantation（P ＞ 0.05）.（2） ComPAred with the CK,different afforestation densities and tending measures significantly promoted the growth of diameter at breast height（DBH）（P ＜ 0.05）,but no significant differences were observed in tree height between different treatments and CK（P ＞ 0.05）.The maximum values of tree height and DBH were observed in the T₃ treatment(1665 plants·hm^-2,full split),which were 16.67% and 75.14% higher than CK,respectively.（3） In the 0—20 cm soil layer, soil acid phosphatase, sucrase, and peroxidase activities of different treatments were higher than those of CK,with increases ranging from 11.13% to 22.89%,8.94% to 47.83%,and 10.08% to 28.38%,respectively.Soil enzyme activity generally showed a downward trend with the increase in soil depth.In summary, the suitable density for two-year-old C.lanceolata container seedlings afforestation is 1665 plants·hm^-2,and the full split measures should be adopted.Under these conditions, relatively satisfactory growth results can be achieved.