Acknowledgements
The study was funded by the National Basic Research Program
of China (Project No. 2011CB100504) and Natural Science
foundation of China (No. 41471187). Mr. Guilong Xia is appreciated
for his careful management of the field experiments in his own
land. Dr. Jiang-Tao Qin is acknowledged to establish the experiment
and the Experimental Ecological Station of Red Soil, Chinese
Academy of Sciences is acknowledged for providing logistical
support and laboratory for this study.