Sustainable Water Use in Urban Agriculture: Innovations and Challenges

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. (After: Nielsen 2002)

15. Container yards: Assessment of irrigation methods ++ very good; +good; -bad; --very bad (After: Nielsen 2002)

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

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

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 m3 / 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 After:Brouwer C & Hwibloem M. 1986

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

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

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

29. .

30. System water supply claim m3/ha/hr for different % of coverage and daily precipitation deficit

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., 2002Markafgrøder, 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