**4. Conclusions**

In this study, the canola plant height, water use from different groundwater levels, total biomass WUE, grain yield WUE, root mass, root-shoot ratio, and harvesting results (total biomass, pod and seed weight) were determined and compared with three different water table depths in a greenhouse. In addition, the effects of the optimum amount of irrigation water and different WTDs on canola were exanimated. Results suggest that the canola plant was affected by different water table levels since inverse linear relationships were found with the different WTDs.

The highest measured pod weight, total biomass, and seed weight were found for plants with the T90 treatment, although plants from this treatment consumed the lowest amount of water from the groundwater. Plants with the greatest harvest results and the lowest amount of water utilization also had the greatest total biomass and grain yield WUEs. On the other hand, plants with the lowest harvest results and the highest crop water use occurred when plants were at the 30 cm water table depth. As a result, a high WTD level (30 cm) negatively impacted the canola growth.

Significant statistical differences were found between the root distribution and soil layers. In addition, stronger and heavier roots were found near the water table level. In contrast, the total root weight was affected by WTD, and significant statistical differences were observed among the treatments. The total root weight of the 90 cm lysimeter was significantly higher than that of the other treatments. It was projected that canola in a drier lysimeter developed its root structure very well, since canola plants have a tendency to reach the water. Overall, the results from this study can be used to guide water management through drainage water management, in order to achieve the best yield potential.

**Author Contributions:** Conceptualization, H.S., X.C. and X.J.; methodology, H.S., X.J. and H.A.; investigation, H.S.; resources, H.H.-V., H.A.; writing—original draft preparation, H.K.; writing—review and editing, H.H.-V., X.J., X.C., H.S.; supervision, H.S.; funding acquisition, H.S.

**Funding:** This research was funded by USDA-NIFA North Central Region Canola Research (grant number FAR0029510), North Dakota Water Resources Research Institute (Grant number FAR0025807), and North Dakota Agricultural Extension Station. Additionally, the Turkish Government Ministry of Education (YLSY program) and General Directorate of State Hydraulic Works (DSI) provided stipend and tuition funding for the M.S. student, Hakan Kadioglu.

**Acknowledgments:** We thank our colleagues Hans Kendal and Mukhlesur Rahman from Plant Science Department and Aaron L.M. Daigh from Soil Science Department at North Dakota State University for their valuable suggestions throughout the study. We are also immensely grateful to Izzet Kadioglu from Plant Protection Department at Gaziosmanpasa University, Tokat, Turkey for his support and encouragement during our experiments. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funding institutions.

**Conflicts of Interest:** The authors declare no conflict of interest.
