Guangyuan Du, Yan Tang, Jianqiang He and Wenting Han

　　College of Sciences, Northwest A&F University, Yangling, China

　　College of Life Science, Northwest A&F University, Yangling, China

　　College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, China

　　Institute of Water-saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, China

　　Optimization of irrigation scheme is a system engineering which does not only relate to technology of irrigation system construction, but also concerns about water status within soil-plant-atmosphere continuum (SPAC). Water content in soil is one of most significant factors that determined the timing and intensity of irrigation. However, water content is only one aspect of ‘available’ soil water that can be used by plants. According to cohesion-tension theory, water long-distance transport from soil, via plant and finally arrive atmosphere is driven by water potential gradient. Water content, combined with soil porosity and solutes concentration determined soil water potential. This study was divided into three parts. Firstly, nuclear magnetic resonance (NMR) was proved to be a prospective tool to quantify the water content and water dynamics in various plant materials, diurnally and in phenological scale. Secondly, NMR was also shown its ability in the determination of water content and porosity of soil samples. Finally, possibility of estimating water potential in soil by NMR methods was analyzed. If this idea was correct, then NMR technology could provide valuable information of real-time water dynamics within SPAC and therefore could be integrated into irrigating scheme.