Understory Vegetation Dynamic Pattern And Soil Characteristic Of Pinus Thunbergii Plantation And Platycladus Orientalis Plantation In Central-southern Mountain Land Of Shandong Province

The undergrowth vegetation and soil evolution can affect the growth,development and community structure of planted forest;moreover,they are each other's essential prerequisites,which would impact the stability and health of plant community.The community succession patterns of plantation ecosystems of Pinus thunbergii plants and Platycladus orientalis plants at different age were studied.The test areas located at the mountain lands of middle south in Shandong Province.The method of the substitution of spatial sere for time sere were used in the paper,and plant community structure,understory vegetation,soil physicochemical properties and microbial community characteristics at different stage were measured.The results showed that:(1)The Simpson index and Pielou index of P.thunbergii plantation was HS6a>HS30a>HS50a.The Shannon-Wiener index was HS30a>HS6a>HS50a,and the diversity indexes of HS50 a was significantly lower than that of HS6 a and HS30 a in undergrowth vegetation(P<0.05).The Simpson index of P.orientalis plantation was CB30a>CB50a>CB12a and the Shannon-Wiener index was CB50a>CB30a>CB12a,which had no significant difference at different age(P<0.05).The Pielou index was CB30a>CB12a>CB50a,and CB50 a was significantly lower than that of CB12 a and CB30a(P<0.05).(2)The soil bulk density of P.thunbergii plantation was HS6a>HS30a>HS50a,and that of HS6 a was significantly higher than HS50 a.The soil capillary porosity of P.thunbergii plantation was contrary to the soil bulk density.The soil bulk density of P.orientalis plantation was CB12a>CB30a>CB50a,and it had no significant difference in separate stand age(P<0.05).The soil capillary porosity of P.orientalis plantation was CB50a>CB30a>CB12a,and it had no significant difference in separate stand age(P<0.05).(3)The soil available phosphorus content of P.thunbergii plantation was HS6a>HS50a>HS30a,which had a significant difference in separate stand age(P<0.05).The soil available content of potassium in P.thunbergii plantation was HS30a>HS50a>HS6a,it had a significant difference in separate stand age(P<0.05).The total and available content of nitrogen in P.thunbergii plantation were HS30a>HS6a>HS50a.The total content of nitrogen in HS50 a was significantly lower than that of HS6 a and HS30a(P<0.05),and the available content of nitrogen in HS30 a was significantly higher than that of HS6 a and HS50a(P<0.05).The available content of phosphorus,nitrogen and potassium in soil of P.orientalis plantation were CB12a>CB50a>CB30a,whereas CB30 a was significantly lower than that of CB12 a and CB50a(P<0.05).The total content of nitrogen in P.orientalis plantation was CB50a>CB12a>CB30a,and there was a significantly difference in separate stand age(P<0.05).(4)The soil invertase activity and soil cellulase activity of P.thunbergii plantation was HS30 a>HS6 a>HS50a,and there were a significant difference in different stand age(P<0.05).The soil urease activity reduced with the increasing stand age,and that of HS50 a was great higher than that of in HS6 a and HS30a(P<0.05).The activity of soil invertase of P.orientalis plantation was CB50 a>CB12 a>CB30a and there was a significant difference in separate stand age(P<0.05).The soil urease activity of P.orientalis plantation was CB50a>CB12a>CB30a and that of CB30 a was significantly lower than that of CB12 a and CB50a(P<0.05).The soil cellulase activity of P.orientalis plantation was CB30a>CB50a>CB12a and that of CB12 a and there was significantly lower than that of CB30a(P<0.05).(5)The soil microbial Chao1 index of P.thunbergii plantation was HS6a>HS50a>HS30a,however,the index of HS6 a was significantly higher than that of HS50 a and HS30a(P<0.05).The soil microbial Shannon index of P.thunbergii plantation was HS6a>HS50a>HS30a,which got a significant difference in different stand age(P<0.05).The Proteobacteria,Actinobacteria and Acidobacteria of were dominant in soil microorganism in P.thunbergii plantation.The soil microbial Chao1 index of P.orientalis plantation was CB50a>CB12a>CB30a,and CB30 a was significantly lower than that of CB12 a and CB50a(P<0.05).The soil microbial Shannon index of P.orientalis plantation was CB12a>CB30a>CB50a,and there was no significant difference in separate stand age(P<0.05).