Long-term alfalfa planting mediates the coupling of soil water and organic carbon storage in a semi-arid area of the Loess Plateau, China 1College of Forestry and Prataculture, Ningxia University, Yinchuan, China 2Ningxia Rural Science and Technology Development Center, Yinchuan, China 3School of Community for Chinese Nation, North Minzu University, Yinchuan, China 4Northern Yanchi Desert Steppe Observation and Research Station of Ningxia, Yanchi, China DOI 10.7717/peerj.18373 Academic Editor...