Crop Et And Implications For Irrigation


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Short presentation on hydrological science being applied to address water management flaws and supply deficits in the Bekaa Valley of Lebanon.

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Crop Et And Implications For Irrigation

  1. 1. Crop Coefficients & Evapotranspiration: Implications for the farmers of Bekka Valley, Lebanon
  2. 2. The Bekka Valley •75 miles X 10 miles •80% of Lebanese Agriculture
  3. 3. Outline • Water Problems • Tal Amara Research Station • Experimental Methods • Sunflowers • Results from other studies • Conclusion
  4. 4. Water Problems • Very long and dry summers – Annual Precipitation: 592 mm – 95% occurs from March to November • Water Mismanagement – Water delivery system is unreliable – Farmers prefer drilling illegal wells rather than relying on public delivery system • Farmer’s education – Do not adopt drip irrigation – Are not provided analytical solutions for optimal irrigation volumes for specific crops
  5. 5. Tal Amara Research Station •Part of a broader movement to provide water and economic security to Lebanon •Experiment in local conditions so results are more applicable •To inform farmers about optimal irrigation volumes during certain growing seasons •Experiment on crop for two growing seasons to determine optimal irrigation Experimental plot (and my tour guide)
  6. 6. Important Terms • Crop yield – Sunflowers produce seeds to be used in consumer products such as cooking oil • Growth stage – For example, sunflowers have an early flowering stage, mid-flowering stage, and seed formation • Deficit Irrigation – Withholding irrigation completely – Irrigating at a percent of soil moisture deficit (I60)
  7. 7. Penman Montieth is used to calculate potential evapotranspiration Data from weather station (ambient weather data @ 10-min intervals) Graph of Bekaa Valley ETp-PM exported to excel file (ie. Dry air (mm/day) for sunflowers density, vapor pressure)
  8. 8. Experimental Plot Reference crop Experimental crop – Rye grass (Lolium perenne) •2,200 sq. m. •Soybean, corn, sunflowers, wheat
  9. 9. Drainage Lysimeter to Measure ET General Schematic (may vary in different locations) 2 x 2 x 1.2 cu Entrance to lysimeter in Bekka Valley Boundary Layer Effect
  10. 10. Sunflowers
  11. 11. Experimental Parameters (Sunflowers) •2 growing seasons •2003: 139 days •2004: 131 days •3 growing stages (deficit irrigation) •F1- early flowering (WS1) •F2- mid-flowering (WS2) •M0- seed formation (WS3) Drip irrigation can provide precise volumes under controlled pressure •Control •Well irrigated crop (C)
  12. 12. More parameters… • ETrye-grass = I – Dr +- S • V = ETcrop x A – Irrigation volume (V) – Plot area (A) • P + I - Dr –R0 –ET +- (Se – Sb) = 0 – Precipitation (P) – Irrigation (I) – Drainage (Dr) – Runoff (R0) – Soil water content (Se) – Water content at beginning of same time interval (Sb)
  13. 13. Results of study Average Kc values •0.3 @ crop establishment •0.9 @ late crop development •>1 @ flowering stage •<1 @ seed maturity Show crops consumptive water use over growing season, needed for sustainable irrigation planning in Bekaa Valley.
  14. 14. Results of study Seed Yields: Control 5.36 t/ha WS1 Reduced yield by 25% WS2 Reduced yield by 14% WS3 Increased yield to 5.5 t/ha These seeds can be used in Water use efficiency consumer products such as increased cooking oil
  15. 15. Other studies Durum wheat •Supplemental irrigation increased grain number per sq. m. and grain weight Soybean •Deficit irrigation (I-60) was profitable in growth stage R7 (late in the growing season) Corn •Not grown before in Bekaa Valley, but studies conclude the Bekka Valley is a suitable place for corn production
  16. 16. Often, water issues are viewed as… A rural African problem…
  17. 17. Or macroscopically…
  18. 18. Views that are in disaccord with reality Each country has a unique government, climate and culture which governs water management there…
  19. 19. References Karam, Fadi. Masaas, Randa. Sfeir, Therese. Mounzer, Oussama. Rouphael, Youssef. 2005. Evapotranspiration and seed yield of field grown soybean under deficit irrigation conditions. Agricultural Water Management. Volume 75. pp. 226-244. Karam, Fadi. Breidy, Joelle. Stephan, Chafic. Rouphael, Joe. 2003. Evapotranspiration, yield and water use efficiency of drip irrigated corn in the Bekaa Valley of Lebanon. Agricultural Water Management. Volume 63. pp. 125-137 Karam, Fadi. Lahoud, Randa. Masaad, Randa. Kabalan, Rabih. Breidi, Joelle. Chalita, Claude. Rouphael, Youssef. 2007. Evapotranspiration, seed yield and water use efficiency of drip irrigated sunflower under full and deficit irrigation conditions. Agricultural Water Management. Volume 90. pp. 213-223 Karam, Fadi. Kabalan, Rabih. Breidi, Joelle. Rouphael, Youssef. Oweis, Theib. 2009. Yield and water- production functions of two durum wheat cultivars grown under different irrigation and nitrogen regimes. Agricultural Water Management. Volume 96. pp. 603-615 AgriMet. 2009. About AgriMet Crop Coefficients. The Pacific Northwest Cooperative Agricultural Weather Network. Webpage. Accessed: October 27, 2009. Photos: Carter’s Facebook (Water Resources of the Middle East) & Google Images
  20. 20. Questions