1. FAU conference, CBS, 14-15 May 2008 Crop water use under urban conditions Chistian R. Jensen Department of Agricultural Sciences, Faculty of Life Sciences, University of Copenhagen

2. Smedema and Rycroft 1983. Land Drainage: planning and design of agricultural drainage systems. Batsford Acad.

3. ET from soil water balance method ET=I + P- RO- DP+ CR± ∆SF ± ∆SW I=irrigation P=precipitation RO= Surface runoff (often large under urban conditions, could be used for water harvesting) DP=deep percolation CR=capillary rise ∆SF=surface flow ∆SW=change in soil water content over time

5. After: Oliver Bühler 2008

6. Efficiency of Water Use (EWU) is affected by genotype, environment & management Litres of water per kg of fresh tomatoes in… Israel (field) 60 Spain (unheated plastic house) 40 Israel (unheated glasshouse) 30 Holland (climate- controlled glasshouse) 22 with re-use of drain water 15 Increasing management save up to 50% fertilizers (Dr Stangellini; Inter-drought II satellite meeting; Sept 2005)

7. Water savings using different irrigation method After: EU water saving potential (2007)

8. Sprinkler irrigation

9. Micro irrigation in an orchard (Naan).

11. Drip irrigation system

12. Container yards in nurseries

13. High tide/low tide irrigation system KVL; NOVO-House

14. Drip irrigationSprinkler irrigation AdvantagesDisadvantagesAdvantagesDisadvantages Smal pumping costs Low water amount Even distribution Easy to add fertilizer Low fungicide need Can be automised High initial costs High water quality No frost protection Many tubes Fixed pot position Frost protection+ Cools, reduce drying Low maintenance Robust and flexible Easy to control Less clogging risk Cheap Low WUE Spill on paths etc. Greater need for fungicides. Difficult to work during watering. Irrigation frame with sprinklers reduce difficulties (After: Nielsen 2002)

15. Container yards: Assessment of irrigation methods ++ very good; +good; -bad; --very bad (After: Nielsen 2002) MethodPriceWorkWater use Distri- bution Wind Sensit. Frost Protec. Fertili- zation Sprinkler ++ -- -++(-) Sprinkler bar --+++/---(+/-) Drip irrigation ---++ --++ Mat irrigation -+++++--+ Sand bed --++++ --+ Low tide/ high tide --++++ --+

17. Potential water saving in agriculture: Conveyance (22%); Irrigation Scheduling (10%), Deficit irr. (10%), Waste water (10%) (After EU Water saving potential, 2007)

20. Latent heat of evaporation (λET ) Absorped Energy (Rn) Wind Leaf : Heating Biochemical processes (CO2-uptake) Heating (H) Sensible heat

21. Evaporation on a typical Nordic summer day Energy in radiation 20000 kJ m -2 For evaporation, 40 % 8000 kJ m -2 Heat of evaporation of water 2450 kJ kg -1 Evaporated water 8000/2450 = 3.3 kg m -2 or 33 tons ha -2 Corresponding to 0.0033 m 3 / m -2 = 3.3 mm Potentiel evaporation, max 6-7 mm day -1 Common evaporation 3- 5 mm dag -1

22. APPROXIMATE VALUES OF SEASONAL CROP WATER NEEDS CropCrop water need (mm/total growing period) Alfalfa800-1600 Banana1200-2200 Barley/Oats/Wheat450-650 Bean300-500 Cabbage350-500 Citrus900-1200 Cotton700-1300 Maize500-800 Melon400-600 Onion350-550 Peanut500-700 Pea350-500 Pepper600-900 Potato500-700 Rice (paddy)450-700 Sorghum/Millet450-650 Soybean450-700 Sugarbeet550-750 Sugarcane1500-2500 Sunflower600-1000 Tomato400-800 After:Brouwer C & Hwibloem M. 1986

23. Measurement of ET from pan evaporation Measurement of precipitation by rain gauge Precipitation Water level ET Mesh (FAO: Class A Pan)

24. ETr from Penman-Monteith equation (Monteith 1971) Rn is the net radiation, G is the soil heat flux, (es - ea) represents the vapour pressure deficit of the air, r a is the mean air density at constant pressure, cp is the specific heat of the air, D represents the slope of the saturation vapour pressure temperature relationship, g is the psychrometric constant, and rs and ra are the (bulk) surface and aerodynamic resistances. λ=heat of evaporation (FAO: See Allen et al. 1998)

25. From ETo and estimates of crop evaporation rates, expressed as crop coefficients (Kc) ETcrop = Kc × ETo

26. Fra tabel 2.5 Max root zone capacity, mm Potatoes Winter rape Soil classificication, JB No.

27. Irrigation scheduling Upward lines are rainfall or irrigation. RAW= readily available water (0-50 % of TAW) TAW=total available water RAW TAW

29. . Time Domain Reflectance TDR equipment for measurement of soil water content

30. System water supply claim m 3 /ha/hr for different % of coverage and daily precipitation deficit Irrigation interval (Days) 2224-10 %coverage 90951009095100 Daily precipita- tion deficit 3.84.25.02.63.25.0 Sprinkler (12 hrs) (4-5 bars ) 2.52.83.31.72.13.3 Drip (24 hrs) (2 bars) 1.11.21.40.80.91.4

31. Take home message Due to dwindling municipal water resources better water management needed by: –Utilizing water havesting of surface runoff water after filtering –Precision irrigation and fertigation, –Measurement of soil water content to control irrigation

32. Ongoing projects at KU/AU Danish Research Counsil:Project : SJVF project 1.9 mill kr. Starting 15/9/04-2009 Physiological basis for improving water use efficiency in crop plants under ‘partial root zone drying (PRD)’ irrigation strategy. Strawberries – New irrigation Techniques (PRD-irrigation) for Better Tast, Quality Keeping and Reducing Pesticide and Water Use. ‘Direktoratet for FødevareErhverv, DFFE. Funding 1.977.345,- kr for 1/1 2007-31/12/2010 Coop project between Research Centre Årslev, Århus University and the Applicant. New Irrigation Schemes. Responsible for Partner 3 UoC Faculty of Life Sciences activities (8 mill kr.) in the SAFIR:EU-project. Safe and High Quality Food Production using Low Quality Waters and improved Irrigation System and Management (Contract No.: 023168 SAFIR) 1/10/2005-31/9/2009. 17 partners 55 mill kr. SWUP-MED: EU-project. Sustainable Water Use Securing Food Production in Dry Areas of the Mediterranean Region. 1/7/2008-31/6/2012. Coordinator S.-E. Jacobsen; EU project with 10 partners, DK IJV KU-Life participants Fulai Liu, C.R. Jensen. Total budget 24 mill kr.

33. Sources: Brouwer C et al. 1985. Irrigation water management: Training manual No. 1- Introduction to Irrigation. http:www.fao.org Brouwer C & Hwibloem M. 1986. Irrigation water mangement: Irrigation water needs. Training manual No. 3. http:www.fao.org Allen et al. 1998. Crop evapotranspiration - Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56 Hagin et al. 2004. Fertigation. Fertilization through Irrigation. IPI Research Topics No. 23. International Potash Institute. CH-4001 Basel Mogensen V.O. 1990. Markvandingssystemer. DSR-forlag Mogensen V.O., Jensen C.R., 2002 Markafgrøder, Klima og Vandforsyning. KVL, Samfundslitteratur KVL-Bogladen. 376 sider. Mogensen V.O., Jensen C.R 2004 Mekaniske Vandingssystemer. Kompendie Nielsen HK 2002. Vandingsystemer til containerpladser. Høyskoleforlaget. Norge. P. 127 Nakayama FS, Bucks DA 1986. Trickle irrigation for crop production. Design, opration, mangemant. Development in Agricultural Engineering 9 Stewaret et al. (Co.editors) 1990. Irrigation of agricultural crops. Agronomy No. 30. ASA