1. Current approaches to assess land use and surface atmosphere interactions: Irrigation, salinity and drought Joop Kroes

2. COST718 Bologna, 14-17 June 2005 Content River basin in India Polder in The Netherlands Irrigation and brackish water Conclusions

3. COST718 Bologna, 14-17 June 2005 Research question Optimize water use and crop production Use of remote sensing Validity of procedures Sirsa district within Haryana state River basin in India

4. COST718 Bologna, 14-17 June 2005 Methodology: Remote sensing Field experiments Scenario analysis: climate, salinity, water distribution, crop growth River basin in India

5. COST718 Bologna, 14-17 June 2005 Results: Remote sensing for land use River basin in India

6. COST718 Bologna, 14-17 June 2005 Results: Remote sensing for land use and ET-estimates Depends on irrigation (rainfall 20% of ET) Compared with modeling results River basin in India rabi (winter) seasonkharif (summer) season

7. COST718 Bologna, 14-17 June 2005 Results: Water productivity (WP) a good performance indicator; relates productivity and water use, example: ‘crop per drop’ River basin in India

8. COST718 Bologna, 14-17 June 2005 Results: Water productivity WP different crops and areas WP to communicate with stake holders (decision makers and water managers) Improve water distribution Minimize groundwater exploitation River basin in India Source: Singh, R (2005): Dissertation Wageningen-UR ( http://www.library.wur.nl/wda/dissertations/dis3711.pdf)

9. COST718 Bologna, 14-17 June 2005 Polder in The Netherlands Problem urbanization climate change-> rising sea level Salinization of ground water and surface water impact on crops include irrigation

10. COST718 Bologna, 14-17 June 2005 Polder in The Netherlands Possible solutions: Find locations for storage Balance the impact of climate and salinity on crops

11. COST718 Bologna, 14-17 June 2005 Salt (Cl - ) tolerances applied in this study Polder in The Netherlands Crop Soil solution Potatoes 750mg/l Grass3600mg/l Forage maize 800mg/l Flower bulbs 150mg/l Irrigation water 200mg/l 950mg/l 200mg/l 50mg/l [Cl - ] in groundwater (mg l -1 )

12. COST718 Bologna, 14-17 June 2005 Method: Land and surface water Waterinlet brackish water Climate scenarios: wet -> extreme dry year Polder in The Netherlands

13. COST718 Bologna, 14-17 June 2005 Conclusions: Much water required for leaching of salts A need for alternatives: Alternative crops Find acceptable salinity ranges Polder in The Netherlands

14. COST718 Bologna, 14-17 June 2005 Saline groundwater in The Netherlands Prediction of salinization increase in 2050 Source: /www.ruimtelijkplanbureau.nl/

15. COST718 Bologna, 14-17 June 2005 Salinization in The Netherlands Prediction of salinization increase in 2050 Source: /www.ruimtelijkplanbureau.nl/ predictions

16. COST718 Bologna, 14-17 June 2005 Purpose: Analyze yield reductions when irrigated with brackish water Balance drought stress versus salinity stress from irrigating brackish water Irrigation with brackish water in The Netherlands

17. COST718 Bologna, 14-17 June 2005 Method: Climate range 1971-2000 Potato crop Loamy and clay soils Irrigated with gifts of 20 mm when soil is dry Irrigation with brackish water in The Netherlands

18. COST718 Bologna, 14-17 June 2005 Results: Irrigation range: 0-300 mm/jr Variation depends on climate, soil type and hydrological conditions Irrigation with brackish water in The Netherlands

19. COST718 Bologna, 14-17 June 2005 Stoneplot 4807 ds-opbrengst Ca (kg/ha) 6000 8000 10000 12000 14000 16000 18000 71 737577 79 81 83 858789 9193 95 97 99 nb0120024005000 A Stoneplot 5206 ds-opbrengst Ca (kg/ha) 6000 8000 10000 12000 14000 16000 18000 71 73 757779 8183 858789 91 93 95 9799 nb0120024005000 B Irrigation with brackish water in The Netherlands Results: salt stress << drought stress, even in dry years (like 1976) irrigation with high salinity levels (>1000 mg/l) is very well possible Fig: Yield versus time nb=not irrigated 0,1200,2400,5000 [Cl] of irrigation water (mg/l)

20. COST718 Bologna, 14-17 June 2005 Irrigation with brackish water in The Netherlands Results: Relative yield decrease around 1500 mg l -1 Drought sensitive soils show rapid yield decrease Relative yield [Cl - ] irrigation water (mg l -1

21. COST718 Bologna, 14-17 June 2005 India and Dutch polders: water with good quality is required to leach down salts and maintain proper yields Dutch polders: Irrigation with brackish water is possible Optimize instead of maximize yields, with more attention for extreme wet conditions Conclusions

22. Thanks for your attention © Wageningen UR joop.kroes@wur.nl