1. College of Water Resources and Architectural Engineering Northwest A&F University Yangling China
2. Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas Ministry of Education Northwest A&F University Weihui Road 23 Yangling Shannxi712100China
3. Department of Plant and Environmental Sciences Faculty of Science University of Copenhagen Højbakkegård Allé 13 Tåstrup2630Denmark