Irrigation A key component of high quality. Farming Systems Research division Ian Goodwin, Senior research scientist

Transcription

1 Irrigation A key component of high quality Farming Systems Research division Ian Goodwin, Senior research scientist

2 Weather Conditions (sunlight, wind, humidity and temperature) Orchard water balance CROP WATER USE Tree Architecture Planting Arrangement Leaf Area Density Understorey Water Use WATER SUPPLY Microjet Drip Wetting Pattern Soil Type Root Distribution Weather Conditions (rainfall)

3 Crop Water Use > Water Supply Water Stress

4 The effects of water stress Yield 100 Yield potential (%) Yield penalty Drainage losses Water Crop supply water relative supply relative to crop to water CWRuse

5 The effects of water stress Fruit size Fruit volume (cm3) % 50% 74% 100% 162% Royal Gala /10 22/10 11/11 01/12 21/12 10/01 30/01 19/02 Date

6 The effects of water stress Total soluble solids Royal Gala Cripps Pink Total soluble solids ( o Brix) LSD (P=0.05) 2008/ / / /12 Total soluble solids ( o Brix) LSD (P=0.05) 2008/ / / / % 50% 74% 100% 162% Treatment 13 38% 50% 74% 100% 162% Treatment Water stress Water stress

7 The effects of water stress Antioxidants Royal Gala ORAC (micromol TE/100g FW) LSD (P=0.05) 2008/ / /11 Total polyphenols (mg GAE/g FW) LSD (P=0.05) 2008/ / / % 50% 74% 100% 162% % 50% 74% 100% 162% Treatment Treatment Water stress Water stress

8 The effects of water stress Cracking Fruit number per tree Total fruit Split fruit Cripps Pink 0 0% 50% 100% 150% 200% Treatment (% of grower practice)

9 The effects of water stress Sunburn Cripps Pink 800 Fruit number per tree Total fruit Sunburned fruit Sunburn necrosis 0 0% 50% 100% 150% 200% Treatment (% of grower practice)

10 The effects of water stress Fruit temperature Temperature (deg C) Air temperature Fruit temperature - 38 % West Fruit temperature % West 0 22/2/12 23/2/12 24/2/12 25/2/12 26/2/12 Date

11 Weather Conditions (sunlight, wind, humidity and temperature) Orchard water balance CROP WATER USE Tree Architecture Planting Arrangement Leaf Area Density Understorey Water Use WATER SUPPLY Microjet Drip Wetting Pattern Soil Type Root Distribution

12 Crop water use Orchard water use = Tree water use + Understorey water use

13 Crop water use Tree water use = 1.3 x EAS x ET o Understorey water use = K e x ET o ET o is reference crop evapotranspiration (water use of grass) EAS is the effective area of shade (convert grass to tree water use) K e is the understorey (soil evaporation) coefficient (convert grass to understorey water use)

14 Reference crop evapotranspiration (ET o ) solar radiation, wind speed, humidity, temperature BOM -

15 Tree water use Effective area of shade (EAS) - the fraction of the orchard floor shaded by the tree - = Shade (am) + Shade (midday) + Shade (pm) 3 i.e. 10 am, 1:30 pm and 5 pm summer time

16 EAS tree size training system planting arrangement leaf area density

17 EAS

18 EAS Row width = 4.5 m Gap fraction of shade = 0.75 Length of shade = 3.5 m Percent shade = Length of shade x Gap fraction of shade Row spacing = 3.5 m x m x 100 = 58 %

19 Understorey water use Irrigation system Microjet K e = 0.2 Drip K e = 0.1

20 Orchard water use Example Microjet irrigated apple orchard ET o = 7 mm EAS = 40 % Understorey coefficient = 0.2 Tree water use = 1.3 x 40 % x 7 = 3.6 mm Understorey water use = 0.2 x 7 = 1.4 mm Orchard water use = = 5.0 mm

21 Weather Conditions (sunlight, wind, humidity and temperature) Orchard water balance CROP WATER USE Tree Architecture Planting Arrangement Leaf Area Density Understorey Water Use WATER SUPPLY Microjet Drip Wetting Pattern Soil Type Root Distribution Weather Conditions (rainfall)

22 Available soil water Unavailable Available Soil Water Unavailable Drainage Readily Available Water (RAW) Deficit Available Water (DAW) Minimally Available Dry Saturation Field Capacity Wilting Point Oven dry soil infinity Soil Water Tension (kpa) Readily Available Water (RAW) GV topsoil = 8 % GV subsoil = 6 % Sandy soil = 4 %

23 Available soil water (1) Total root-zone Readily Available Water When to initiate irrigation - Root distribution - Soil type (i.e. RAW) Example: Fibrous root-zone depth = 400 mm Lateral root distribution = 75 % RAW = 8 % Total root-zone RAW = 400 x 75 % x 8 % = 24 mm

24 Available soil water (2) Wetting pattern Readily Available Water Optimum irrigation run time (hour) - Fibrous root-zone depth (400 mm) - Emitter rate and coverage - Soil type (i.e. RAW) Soil type Drip Microjet 1.6 l/h 2.3 l/h 25 l/h 35 l/h (r = 1.4 m) (r = 1.8 m) Sandy clay loam 7 h 5 h 5 h 4 h Clay loam 8 h 6 h 6 h 5 h Sand 3 h 2 h 3 h 3 h

25 Water budgeting Apple Orchard Water Budget Month Long-term Effective Basal Crop Soil Evaporation Orchard Average Soil Stress Irrigation Average ETo Area of Shade Coefficient Coefficient Water Use Rainfall Reserve Coefficient Requirement (mm) (%) (mm) (mm) (mm) (mm) September October November December January February March April May TOTAL (mm) TOTAL (ML/ha) Effective Rainfall (%) 75 Soil Water Reserve in Root-zone Layer Root-zone extent Soil RAW or DAW Soil Reserve Depth (mm) Lateral (%) Texture (%) (mm) sandy loam clay loam TOTAL ETo 160 Water Use 140 Irrigation

26 PIPS-ET Calculator

27 Irrigation scheduling plan Irrigation Scheduling Plan Location Manjimup Tree Spacing (m) 2 Block south east Row Spacing (m) 5 Variety Royal Gala Emitter Output (litre/hour) 30 Clone Emitter Spacing (m) 2 Rootstock Laterals per Row 1 Month Irrigation Irrigation Long-term Basal Soil Stress Tree x Daily Irrigation Run Time Amount Average Crop Evaporation Coefficient Row Water Interval ETo Coefficient Coefficient Spacing Use (hour) (litre/tree) (mm/day) (square m) (litre/tree) (day) September October November December January February March April May

28 Real-time irrigation scheduling

29 Soil moisture monitoring Fine tune: Irrigation run time Crop coefficient (i.e. orchard water use) When to irrigate after rainfall

30 Soil moisture monitoring

31 Soil moisture monitoring sensors

32 Satellite remote sensing Orchard water use ET/ETR JAN NDVI Source: O Connell, PhD thesis

33 Orchard stress monitoring

34 Orchard water use and stress monitoring

35 Thank you Questions