9WangK-B(王凯博),ShiW-Y(时伟宇),Shang-guangZ-P(上官周平).Effects of natural and artificialvegetation types on soil properties in loess hilly region. Transactions of the Chinese Society of Agricultural Engi- neering, 2012, 28 ( 15): 80-86.
10Zhang L X,Bai Y F, Han X G~ Application of N:P stoichiometry to ecology studies[J].Acta Botanica Sinica, 2003,45(9): 1009-1018.
