ALTERNATIVE IRRIGATION SYSTEMS. Marc van Iersel Associate Professor, Floriculture Griffin Campus, UGA

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1 ALTERNATIVE IRRIGATION SYSTEMS Marc van Iersel Associate Professor, Floriculture Griffin Campus, UGA

2 Any unconventional way to water a crop Not: Hand watering Overhead sprinklers Drip irrigation

3 Why use alternative irrigation systems? Reduce nutrient + pesticide run off Water conservation Economics!

4 Two types of watering systems Open cultural systems Closed cultural systems (recirculating)

5 Background Much of the knowledge comes from plant nutrition experiments (both systems and nutrient solutions) Most famous: Hoagland Solution (1950)

6 Specific Systems Hydroponics (nutriculture) The culture of plants in an inert substrate Fertilizer has to contain all nutrients Substrate does not alter nutrient solutions

7 Possible substrates: Air Water Gravel Sand Rockwool Expanded clay

8 Two common hydroponic systems Nutrient Film Technique (NFT) Rockwool culture

9 Nutrient Film Technique Plants are grown in sloped (1-4%) channels Nutrient solution is pumped into the top of the channel and drains back into nutrient solution tank

10 Nutrient Film Technique Channels need to be covered: Minimize evaporation Prevent algal growth Control root temperature Prevent inhibition of root growth by light

11 Nutrient Film Technique Vegetables Cut flowers Herbs

12 Nutrient Film Technique Advantages No soil pasteurization Water and nutrient conservation Automation

13 Nutrient Film Technique Disadvantages Higher cost Threat of disease spread Long channels can cause nutrient deficiencies

14 ROCKWOOL CULTURE Plants are grown in slabs of rockwool Rockwool Not biodegradable Low CEC Not buffered

15 ROCKWOOL CULTURE Transplants are grown in small rockwool blocks These blocks can then be placed in or on larger rockwool slabs Plants are watered several times per day with nutrient solution (Open or closed system)

16 ROCKWOOL CULTURE Because plants are grown in rockwool slabs, they cannot removed Most suitable for: Herbs Vegetables Cut flowers

19 ROCKWOOL CULTURE Advantages No soil pasteurization need Can be re-used (but must be pasteurized) Excellent inert substrate Light substrate; plants can easily be moved

20 ROCKWOOL CULTURE Disadvantage: Disposal of rockwool

21 EBB-AND-FLOW (Ebb-and-flood, flood-and-drain, flood floor) Closed sub-irrigation system Plants are grown on a watertight bench Nutrient solution is pumped onto the bench and drained back into tank Suitable for any container-grown crop

22 EBB-AND-FLOW Plants are normally grown in standard soilless media Some fertilizer can be mixed into the medium (lime, P) Ebb-and-flow systems can also be built into greenhouse floor (flood floors)

26 EBB-AND-FLOW Nutrient solution can be maintained automatically with EC, ph controllers and float valve or Replenished periodically

27 Advantages: Little disease spread Foliage is kept dry Water, fertilizer savings Reduced labor requirements Very flexible Uniformity

28 Disadvantages: Expensive Possibility of high RH Possible fertilizer accumulation

29 TROUGH CULTURE Combination of NFT and Ebb-and-Flow Potted plants are grown in sloped, watertight troughs Closed system, nutrient solution is recycled Plants are watered as needed, long enough to wet the growing medium

31 TROUGH CULTURE Advantages: Cheaper than ebb-and-flow Better air circulation

32 TROUGH CULTURE Disadvantages: Not very flexible Inefficient use of greenhouse space if troughs and pot size are not matched

33 CAPILLARY MATS Plants are grown on porous mats and subirrigated by keeping the mat wet The mat needs to be kept moist at all times (hard to rewet)

34 CAPILLARY MATS Advantages: Very flexible Low cost, easy installation Almost no run-off Keeps foliage dry

35 CAPILLARY MATS Disadvantages: Good contact needed between mat and pots (no trays!) Possibility of algae (use black plastic as cover) Raises humidity Salt build-up at medium surface Roots may grow into mat

36 There is an important difference between overhead irrigation and subirrigation

41 IMPROVEMENTS IN SPAGHETTI TUBING DRIP EMITTERS Slow and steady flow of water Allows for better water distribution Most emitters can be turned on or off individually

45 IMPROVEMENTS IN SPAGHETTI TUBING PULSE IRRIGATION Plants are watered with spaghetti tubing, but only for short periods at a time Plants need to be watered more frequently than with regular spaghetti tubing Can easily be automated Needs to be designed carefully to achieve even watering

46 MONITORING FERTILIZER LEVELS EC dsiemens/m (ds/m) msiemens/cm (ms/cm) msiemens (ms) mmho

47 MONITORING FERTILIZER LEVELS Optimal range: ds/m ph ( )

48 POUR THROUGH METHOD Simple way to monitor EC and ph

51 The End

Plant Propagation for Successful Hydroponic Production

Plant Propagation for Successful Hydroponic Production Hye-Ji Kim Assistant Professor of Sustainable Horticulture Crop Production Oct 14, 2017 What is Hydroponics? Hydroponics = hydros + ponos Water labor