基于TRU系统对三种不同立地条件下川山茶根系空间分布的研究

Study on root system distribution of Camellia szechuanensis Chien based on TRU system at three different site conditions

采用TRU系统对种植于南山植物园山茶园、龙茶花海和永川区道路、公园绿地内的川山茶(Camellia szechuanensis Chien)进行根系非破坏性检测,测定了距树干0.5 m和1.0 m圆断面处粗度≥1 cm根的数量和分布范围,以对比不同生长条件下川山茶根系的分布特点,探索川山茶园林应用的限制因子。同时,采集土壤样品7个,分别测定土壤pH、EC值、有机质含量等8项指标。结果表明,①从距树干0.5-1.0 m,粗度≥1 cm根系分布范围呈扩大趋势,最深深度在62 cm左右,最浅深度可达地表;②从距树干0.5-1.0 m,≥1 cm粗的根数逐渐增加。其中,山茶园≥1 cm粗的根数从20个增加至35个,龙茶花海从34个增加至46个,永川区园林应用茶树从11个增加至13个;③山茶园78%-85%的≥1 cm粗根系分布在20-72 cm的土层中,龙茶花海80%-82%的≥1 cm粗根系分布在0-40 cm的土层中,永川区园林应用茶树约50%的粗度≥1 cm根系分布在0-20 cm土层中;④与南山植物园山茶园和龙茶花海相比,距树干0.5 m和1.0 m的圆断面处,永川区调查点相同径级茶树≥1 cm粗的根数较少,根系分布较浅,根系的延伸能力较差,这与调查地点土壤质量差密切相关。总之,改善种植土壤质量,并更换根系主要分布深度土壤,对促进园林应用川山茶生长势恢复有重要作用。

Based on the TRU system,the root system of Camellia szechuanensis Chien planted in Nanshan Botanic Garden,Longcha Huahai,and Yongchuan Road and Park Greenbelt was measured at 0.5 m and 1.0 m circle of the trunk,the number and distribution range of diameter≥1cm roots were measured,in order to compare the distribution characteristics of roots under different site condi⁃tions,explore the limit factors of its application in road and park greenbelt.Meanwhile,7 soil samples were collected,8 indexes were measured for each soil sample,such as soil pH,EC and organic matter content and so on.The results showed that:(1)at a distance of 0.5 m to 1.0 m from trunk,the depth of diameter≥1 cm root distribution is increasing,at a range of 0-62 cm;(2)at a distance of 0.5 m to 1.0 m from trunk,the number of diameter≥1 cm roots increases gradually.Among them,The number of diameter≥1 cm roots in⁃creased from 20 to 35 in Nanshan Botanic Garden,from 34 to 46 in Longcha Huahai,from 11 to 13 in Yongchuan district;(3)78%-85%of diameter≥1 cm of roots distributed in 20-72 soil layer in Nanshan Botanic Garden,80-82%of diameter≥1 cm of roots dis⁃tributed in 0-40 cm soil layer in Longcha Huahai,about 50%of diameter≥1 cm roots distributed in 0-20 soil layer in Yongchuan dis⁃trict;(4)Compared with Nanshan Botanical Garden and Longcha Huahai,at a distant of 0.5 m and 1.0 m from trunk,the tree planted in Yongchuan district with the same diameter showed less root number,root distribution and root extension.This is closely related to the poor soil quality at the survey site.Anyway,improving the soil quality,especially the depth of main roots distribution,plays an im⁃portant role in promoting the restoration of C.szechuanensis Chien growth.