1. Maziar M. Kandelous (mkandelous@ucdavis.edu)mkandelous@ucdavis.edu Barzin A. Moradi Optimization of water and nitrate application efficiency for Citrus trees: recommendations for irrigation and fertigation practices 1

2. Background Information What do we do (Objectives)? Why do we do what we do (The importance of the work)? How do we do (Methodology)? Who get benefits from what we do (Benefit to Citrus Industry)? 2

3. Monitor the water and fertilizer application Monitor the water and fertilizer leaching Find possible solutions for the discovered issues Provide recommendation to help farmers maintaining/improving the yield while following the regulation Objectives 3

4. Application How much water we apply? Is it uniformly distributed? How much nutrient we apply? Is it uniformly distributed? What is the evapotranspiration demand? Is it uniform? 4

5. Leaching Water Balance Darcy Law 5

6. Water Balance 6

7. Cumulative leaching (cm) DripFanjet 7

8. Darcy Law 8

9. Total head gradient 9

10. Darcy Law Total head gradient 10

11. Darcy Law Total head gradient 40cm A B q 11

12. Darcy Law Soil hydraulic conductivity 12

13. Darcy Law Soil #1Soil #2 13

14. Darcy Law 14

15. Darcy Law 15

16. 16

17. Just an example

18. Darcy Law 18

19. Study Site 19

20. Results - Mandarin 20

21. Results – Orange 21

22. Benefit to Citrus Industry Self-monitoring of water/nitrate leaching Monitoring of soil profile water status Site dependent irrigation management Site/Crop dependent fertigation management 22

23. How will industry implement your results Citrus grower as end user will have better understanding of managing their farm and improve it (if indeed needed) This study will result a guideline on how to use the available technologies to better manage each specific orchard? 23

24. One thing to remember No one should tell you that you need to eliminate your leaching Based on the quality of water you have you are required to add more water than required to leach the salt out of root zone You just want to make sure that you have no nutrient (Nitrate) in your leaching water 24