Effects of Nitrogen and pH Treatment on Seedling Growth of Eucalyptus urophylla × E.grandis-Dallergia odorifera Intercropping Systems
In order to provide a scientific basis for exploring sustainable management of Eucalyptus plantations with high-efficiency biological nitrogen fixation,this study explores the response of root nodules,seedling growth and physiology to different nitrogen application and pH environments under the intercropping system of legume species Dalbergia odorifera and Eucalyptus urophylla ×E.grandis.Adopting controlled pot experiments to simulate the intercropping system of D.odorifera and E.urophylla × E.grandis.The experiment was carried out by using a two-factor complete randomized block design,nitrogen(N)and pH with four concentration gradients were set to control the experiment:N1,N2,N3,N4 and pH4.5,pH5.5,pH7.5 and pH9.5,respectively.The results indicate that:1)Under N2 and N3 treatments,the nodule formation ability of D.odorifera was significantly inhibited(P＜0.05).However,there were no significant differences between the N1 level and the control group(CK)in root nodule formation ability,and the root nodulation ability was strongest at pH7.5.2)The biomass and photosynthetic indexes of E.urophylla × E.grandis increased with the rise of N application.Except for pH9.5 treatment,those of D.odorifera initially increased but then decreased with increasing N application.3)The content of superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),and nitrate reductase(NR)of D.odorifera and E.urophylla × E.grandis.leaves were increased with N application,while the content of malondialdehyde(MDA)showed the opposite trend.4)Except for the N3 treatment,the biomass of E.urophylla x E.grandis and D.odorifera seedlings were significantly higher under pH5.5 treatments than that of pH4.5 and pH9.5 treatments.5)The results of redundancy analysis showed that the nodule ability of D.odorifera in the intercropping system was limited by the physiological condition of D.odorifera and biomass of E.urophylla × E.grandis.In conclusion,moderate nitrogen addition and soil pH regulation are beneficial for the mutual development of D.odorifera and E.grandis seedlings in this system.
Eucalyptus urophylla × E.grandisDalbergia odoriferaroot nodulegrowth and physiologyinter-cropping
NETL
NSTL
万方数据
