Affiliation: | 1 College of Economics & Management,Northwest A&F University, Yangling 712100, P.R.China2 Knowledge Technology and Innovation Group,Wageningen University, Wageningen 6706KN, The Netherlands3 College of Resources and EnvironmentalSciences, China Agricultural University, Beijing 100094, P.R.China4 Agricultural Information Institute, ChineseAcademy of Agricultural Sciences, Beijing 100081, P.R.China |