不同栽植基质对上海市4种行道树表型生长和根系发育的影响

Effect of Planting Substrate on Phenotypic Growth and Root Development of 4 Street Tree Species in Shanghai

[目的]揭示4种不同类型行道树的生长规律及其对地下土壤结构、养分和水分供需关系的适应情况,探索适于上海市行道树的土壤结构和养分等管理模式,以改善上海市行道树生长状况。[方法]采用土壤填充颗粒粒径、结构土比例以及基质湿度3因素4水平的正交试验设计,研究4种行道树在不同栽植基质下地上部分表型生长和根系发育状况。[结果]结果表明:不同栽植基质对悬铃木苗高有显著影响,对4种行道树根系发育及根系生物量积累均起到极显著作用。处理3栽植基质的悬铃木苗高最高(4.42 m),较对照组均值显著高出11.90%。4种树种根系发育的最佳栽植基质各不相同,处理8栽植基质下香樟根系发育最为优越,其根系总长、根系表面积和根系体积分别为162 564.21 cm、42 370.89 cm^2和833.98 cm^3,均显著高于对照等其它处理。银杏除根系总长在处理4栽植基质下达到最大值(26 498.01 cm),其余根系指标均在处理7栽植基质下发育较好,显著优于对照等其它处理。处理2栽植基质下悬铃木根系总长、根系表面积、根系平均直径和根系体积均显著高于其它处理。广玉兰根系生长指标均在处理6栽植基质下达最大值。香樟、银杏、悬铃木和广玉兰根系生物量分别在处理8、处理7、处理2和处理6栽植基质下达到最大,其最大值分别为1 029.52 g、871.93 g、1 294.84 g和1 025.62 g,且分别显著高出对照组均值80.44%、67.08%、61.21%和81.36%。通过模糊函数隶属法初步筛选出适宜香樟、银杏、悬铃木和广玉兰种4种行道树生长的栽植基质分别为处理8(土壤粒径3 cm,结构土比例80%,土壤湿度50%)、处理7(土壤粒径3 cm,结构土比例60%,土壤湿度40%)、处理2(土壤粒径5 cm,结构土比例40%,土壤湿度60%)和处理6(土壤粒径3cm,结构土比例40%,土壤湿度80%)。[结论]香樟生长对栽植基质水肥条件较敏感,适宜生长于水分适中、养分含量高的基质中;银杏较适生长在土壤通气良好、养分中等的立地,且其对水分要求相对较低;悬铃木适宜于通气性良好,水分和养分条件较好的基质中;广玉兰生长对基质含水量需求较大。对4种行道树进行养护时应根据其生长需求特点尽可能进行土壤水肥等条件控制。

[Objective] Aim to reveal the growth patterns of 4 street tree species and how they adapt to the change of relationship between soil structure, nutrient and water condition. And to explore the management model of soil structure and nutrients suitable for the street trees in Shanghai, so as to improve their growth in Shanghai. [Method] Planting substrate experiments were carried out by orthogonal design with three factors of soil content diameter, the proportion of structure soil and soil moisture, each in four levels. The growth of aboveground parts and the root expanding of these trees under different conditions were analyzed. [Result] The results showed that the planting substrate had significantly influences on the height of Platanus orientalis. The height in treatment 3 was 4.42 m and significant higher （11.90%） than that of the control group. In addition, different treatments significantly influenced the tree＇s root expanding and biomass accumulation. The results indicated that the most suitable condition for roots growth of the four tree species were totally different, Cinnamomum camphora had the best root growth with treatment 8, the root length, surface area and volume were 162 564.21 cm, 42 370.89 cm^2 and 833.98 cm^3, which were all significant higher than that of the other treatments, respectively. While the total length of Ginkgo biloba root reached the maximum （26 498.01 cm） under treatment 4, and the other root indexes reached the biggest value with treatment 7. The root length, root surface, root average diameter and root volume of P. orientalis are significantly higher under treatment 2. All the root indexes of Magnolia grandiflora reached the maximum under treatment 6. Furthermore, the maximum root biomass value of C. camphora, G. biloba, P. orientalis and M. grandiflora were 1 029.52 g, 871.93 g, 1 294.84 g and 1 025.62 g and appeared in treatment 8, treatment 7, treatment 2 and treatment 6, respectively. Moreover, they were significant higher than that of the control group by 80.44%, 67.08%, 61.21%, and 81.36%, respectively. Through fuzzy membership method, the appropriate substrates selected for C. camphora, G. biloba, P. orientalis and M. grandiflora were treatment 8 （granule diameter 3 cm, formula soil 80% and soil moisture 50%）, treatment 7 （granule diameter 3 cm, formula soil 60% and soil moisture 40%）, treatment 2 （granule diameter 5 cm, formula soil 40% and soil moisture 60%） and treatment 6 （granule diameter 3 cm, formula soil 40% and soil moisture 80%）, respectively. [Conclusion] It proves that the growth of C. camphora is more sensitive to water and nutrition condition of substrate and the suitable growth conditions are moderate soil moisture and rich soil nutrient content. G. biloba should grow in soil with medium nutrient and ventilation, and likes lower substrate water moisture; P. orientalis is suitable in well ventilated, medium water content and nutrient conditions; And M. grandiflora demands higher substrate moisture. Therefore, the conservation of the 4 tree species should be based on the demand characteristics of growth as far as possible to control soil conditions of street site in Shanghai.