Outline of todays discussion WUE o Total amount per crop o Timing of - - PowerPoint PPT Presentation

Outline of todays discussion

 WUE

• Total amount per crop
• Timing of water applications
• Understanding the critical stages of crops
• Irrigation scheduling

 Prioritising watering when water in short supply  Rotations (water profile)

Comments / Questions?

 Depends on type of crop  Crop water use changes with the stage of growth  Evapotranspiration is the term used to describe the

combined losses by evaporation and transpiration (plant water use).

 When a crop is actively growing the majority of water use is

transpiration.

1.

Solar radiation

2.

Humidity

3.

Wind speed

4.

Temperature

1.

The stage of growth of the crop

2.

The depth of the plant/ crop root system

3.

The field capacity of the soil



The amount should fill the rooting zone and no more.

1.

The area of transpiring surface

2.

The rate of transpiration

3.

The rate of evaporation from the soil

4.

The field capacity of the soil

(mm of water per 1 metre depth of soil)

 Sand

30

 Loamy sand

40

 Sandy loam

50

 Sandy loam with OM

80

 Loam

90

 Clay

40

 Well structured clay

70

Crop Irrigation Depth (mm) Irrigation (ML/ha) Potatoes 300 – 400 3.5 – 6.0 Peas 100 – 200 1.0- 2.0 Poppies 150 – 300 1.5 – 2.5 Green Beans 200 2 – 2.5 Pyrethrum 100 – 150 1 – 1.5 Carrots 350 3.5 Onions 350 – 400 3.5 – 4.0 Broccoli 200 – 250 2.0 – 4.0 Lucerne 350 – 550 3.5 – 5.5 Pasture 350 - 550 3.5 – 5.5

“Law

• f
• f th

the minimu mum” m”

B Cu Ca K S Fe Zn Mg N Mn Mo

“Law

• f
• f th

the minimu mum” m”

Diseases Sow date water

• log

Nutrition Insects Plant density Weeds Tiller density frost Radiatio n Variety Environmental lodge

10 20 30 40 50 60 70 80 90 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Monthly r ly rainfall ( ll (mm) GSR = 523 m = 523 mm

Attainabl tainable grain in yield d (Hag Hagley)

= (water u use se – ET) x x WU WUE = (525 = (525 + 50 + 50 – 125) x 125) x 20 20 = 450 = 450 x 20 20 = = 9000 9000 k kg/ha

Monthly r ly rainfall ( ll (mm) GSR = 459 m = 459 mm

10 20 30 40 50 60 70 80 90 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Attainabl tainable grain in yield d (Cre ressy)

= (water u use se – ET) x x WU WUE = (450 = (450 + 25 + 25 – 125) x 125) x 20 20 = 350 = 350 x 20 20 = = 7000 7000 k kg/ha

plants/ s/m2 ear ars/pla lant spikele lets/ear grai ains/spikele let grai ain w weight

Sadras and McDonald, 2012

 15

15 t/ha

• irrig

igat ated d 6X 6X @ @ 40 m 40 mm ie ie 240m 40mm

• GS

GSR = = 505 m 505 mm

 Yi

Yield - 40% 40% higher o r over 4 r 4 yr yrs

 Ears/m

s/m2 - no dif difference

 Grain

ins/e s/ear ar - 13 13% highe her

 Grain

n wt wt - 22% 22% hi highe her

WATER F R FOR R PR PROFI FIT

Water Use Efficiency, Critical crop Stages and Timings for Optimal Water Use, Pastures, Grass Seed, Clover Seed, Carrot Seed, Onions and Brocolli Tom Graesser

Irrigated P Pastur ures

• Dairy Tas aim 1000 kg Dry matter per 100mm per ha

(1ML)

• $2-300 Drymatter per ML water?
• Healthy perennial pastures(rye/white clover)
• Pasture water use approx.= Full Pan evaporation
• Rooting depth generally less than

60 cm

• Need efficient system cost wise to

pay for fully irrigated(5-6 ML/Ha)

• Most efficient use is to start off a

newly sown pasture or strategic water.

Lucern rne

• Deep rooted, 1m or more
• More efficient moisture use than ryegrass/white clover
• Approx $600 gross value Lucerne per ML water (well

managed, 2t/ML)

• 4-5 ML/ HA per season
• Critical to have well watered

to about 3-4 days before cutting and fertilized and irrigated immediately after hay/silage removed

Ryegr egrass S Seed ed Prod

• duction
• Oregon and NZ work- Extra 4-8 kg clean seed per mm

($1000/ ML)

• Most critical growth stage 2 weeks leading up to

flowering

• Second most responsive period 1-3 weeks after start

flowering (ie up to within week of windrowing)

• Anecdotally, in dry year like last

year, big gains from maintaining adequate moisture after closing through to flowering.

White Clover r Seed

• Approx $1200/ML
• Critical stages are establishment early in Autumn

and spring bulking up Mid Oct to Mid Nov

• During Bulking up, need full Pan Evaporation

replacement, aiming for about 3t drymatter by start flowering

• During flowering and seed fill;

controlled moisture stress-growthy paddocks about 33% full evaporation, others about 50%. More is not better!

Onions ns

• 3-4 ML/ha, $2000/ML
• Even establishment critical
• Adequate moisture and growth 3-8 leaf stages for

good symmetrical bulb shape

• Water use drops to about 80

% of Pan Evaporation from mid bulbing onward

• Night time irrigations best to

Minimize Botrytis

Hybri rid Carrot S Seed

• 5 ML/ha, $2000/ML
• Establishment critical
• Full Irrigation/rain up to flowering
• Flowering to Harvest; Drip better Germination,

yield and lower disease than overhead irrigation BUT overhead OK if overnight only and 20+ mm applications.

• Anecdotally restrict moisture to

about 25mm per week (60% full evaporation) during flowering/seed fill.

Broc

• ccol
• li
• 3-4 ML/Ha,
• Even establishment of crop critical to keep harvest

costs down and maximize yields; Green Harvest

• Shallow rooted- mature crop only

about 40cm depth, first week 4cm.

• Final week suggest under-watering

Slightly to minimize risk of wet harvest (70% evaporation).

 Sprout development  Vegetative growth  Tuber initiation  Tuber bulking  Maturation

Questions?

 Establishment  Post herbicide  Run up  Hook  Flowering  Stripey Capsule

Questions?

 Soil moisture deficit reduces

growth and can impact on nodulation

 Moisture stress during

flowering and pod fill can severely limit yield and quality

 Excess water can limit yield

(yellowing)

Questions?

 Beans should be planted into moist soil

and irrigated soon after

 Beans are sensitive to water stress

during flowering, pod set and pod enlargement.

 Avoiding moisture stress during crop

growth will aid in creating a moist, crisp bean.

 Lower production may be experienced if

inadequate water is provided during pod enlargement leading up to harvest.

Thank you