缓释肥N/P比及加载量对5种珍贵树种1年生苗生长和养分库构建的影响

【目的】 揭示不同缓释肥N与P₂O₅质量比(N/P比)及加载量对浙江楠等5种珍贵树种1年生容器苗生长、N与P素吸收利用及养分库构建的影响,以期为精细化培育珍贵树种容器苗提供科学指导。【方法】 采用4×4两因素析因设计,研究N/P比和加载量对浙江楠等5种珍贵树种1年生容器苗生长发育及N、P库构建的影响。【结果】 缓释肥N/P比、加载量对5树种1年生容器苗生长和干物质积累均有显著或极显著影响。随着N/P比提高,各树种的反应却不一致;当缓释肥加载量为F3(3.5 kg/m³)时, 5树种生长指标和干物质积累均达到最大值。浙江楠、浙江樟和木荷的叶N含量与缓释肥N/P比密切相关,但南方红豆杉和赤皮青冈叶N含量在各N/P比间差异不显著。除浙江楠外,其他4树种的叶P含量在不同N/P比下差异显著,但各树种叶N和P累积量却对N/P比响应均不敏感。较之于N/P比,缓释肥加载量对5种珍贵树种1年生容器苗N、P库构建的影响更明显,叶N、P含量及累积量均在较高的缓释肥加载量F3下达到最高。N、P含量在各树种器官内的变化规律基本一致,说明N、P吸收同步,但不同树种间N、P素在各器官的分配却不同。【结论】 浙江楠容器苗生长及其养分库构建均需高N缓释肥,浙江樟、赤皮青冈和木荷则需要相对高P缓释肥,而南方红豆杉容器苗生长对N/P比要求不严格,但其养分库构建需高N缓释肥;在考虑N/P比的同时,适量(3.5 kg/m³)增施缓释肥,可提高珍贵树种的容器苗质量。

Effects of N/P ratio and loading on growth and construction of nutrients reserves of one-year-old seedlings for five kinds of precious tree species

【Objective】To provide scientific guidance for seedling cultivation in containers,the impacts of slow-release fertilizer(SRF)loading were observed for the growth,nitrogen(N)and phosphorus(P)uptake,and nutrient pool construction of five precious tree species,such as Phoebe chekiangensis.【Method】A 4×4 factorial experimental design was used to compare the impacts of the N/P mass ratio(1.75:1,2.25:1,2.75:1 and 3.25:1)and SRF loading levels(1.5,2.5,3.5 and 4.5 kg/m3)on the growth and N and P nutrient pool construction of one-year-old seedlings.【Result】Significant effects were detected in the growth and dry matter accumulation between N/P ratios,SRF loading,and their interaction.As the N/P ratio increased,the tree species responded differently.The largest growth and dry matter accumulation of the five precious tree species was detected with 3.5 kg/m^3 SRF loading.The N concentration in the leaves of P.chekiangensis,Cinnamomum chekiangense and Schima superba was correlated with the N/P ratio,but there was no difference in the leaf N concentration of Taxus wallichiana and Cyclobalan gilvain.The P concentration in the leaves of all species,except for P.chekiangensis,also significantly differed with varying N/P ratios.However,the N and P accumulation in the leaves of all species were not sensitive to the N/P ratio.The effect of the SRF loading on the nutrient accumulations was more obvious than the N/P ratios;the concentration and accumulation of leaf N and P were highest with 3.5 kg/m^3 SRF loading.Changes in the N and P concentrations in the organs of the different species were similar,indicating N/P absorption synchrony,whilst the distribution of N and P among the organs was species-specific.【Conclusion】Based on the growth characteristics of the different tree species,seedlings of P.chekiangensis should be loaded with higher N content fertilizer,and the seedlings of Cinnamomum chekiangense,Cyclobalan gilva and S.superba should be loaded with higher P content fertilizer.T.wallichiana seedlings are not sensitive to the N/P ratio,but nutrition construction suggests that it is N/P ratio and adding appropriate amounts of SRF(3.5 kg/m^3).