Effects of Effective Microorganisms on the Growth of 1-Year-Old Container Seedlings of Three Tree Species

An experiment was conducted to determine the effects of effective microorganisms (EM) solution diluted 500 times on the growth of 1yearold container seedlings of three tree species, Phoebe zhennan, Sapindus mukorossi and Michelia macclurei. Treatments included control (CK), foliar topdressing (L_EM), substrate topdressing (R_EM), combination foliar and substrate topdressing (L+R) _EM. The end of July to end of August, the fast growth in seedling height was observed. With respect to rapid growth in ground diameter，early September was for S. mukorossi and midSeptember was for both P. zhennan and M. macclurei. Application of EM could regulate the growth both plant height and ground diameter compared with CK. Before the rapid growth period in plant height, the average height growth rate of M. macclurei, P. zhennan and S. mukorossi respectively increased by 133%, 39% and 248% in the R_EM treatment, and respectively increased by 217%, 256% and 331% in the (L+R) _EM compared to CK. During the rapid growth period, the average height growth rate of the three species was increased by 11%-88% in R_EM and (L+R)_EM compared to CK. The period of rapid growth in ground diameter was not affected by L_EM for the three species, whereas the process was in advance in R_EM for P. zhennan and M. macclurei except, S. mukorossi. The ratio of height to diameter (HDR) decreased in R_EM and (R+L)_EM compared to CK. At the end of experiment, HDR of M. macclurei, P. zhennan and S. mukorossi decreased by 700%， 420% and 560%, respectively in (L+R)_EM. Application of EM could promote root growth of all species. Compared with the control, the increases of the parameters of roots such as root volume and root weight were observed in L_EM, R_EM and (L+R) _EM: root volume increased by 1604%, 4074% and 8074%. The volume of lateral roots was increased by 2490%, 5136% and 10003%, respectively. Root fresh weight was increased by 2000%, 3580% and 7599%, respectively. Root dry weight was increased by 619%, 2845% and 6619%. In addition, the dry weight ratio of root to stem in L_EM， R_EM and (L+R)_EM compared to CK was increased by 1385%, 2191% and 3940%, respectively. As a result, it was significance for improving the quality of 1yearold container seedlings using EM solution diluted 500 times to substrate topdressing.