Irrigated agriculture R&D underpinning practice/change: - - PowerPoint PPT Presentation

Department of Sustainability and Environment Department of Primary Industries

Irrigated agriculture R&D underpinning practice/change: hydrology research

Lucy Finger February 2008

Hydrology group research

• Salinity impacts of water trade
• Water use efficiency benchmarking
• Irrigation Futures
• Scenario development – agriculture adaptation to climate change
• Improving irrigation practices (dairy industry)

– Border-check irrigation – Irrigation technology comparison – Sprinkler irrigation – Subsurface drip irrigation

What is subsurface drip irrigation?

• Water supplied to rootzone via tube
• Low operating pressure, low flow rates (<5 L/hour)
• Continuous or pulsed application
• Fertigation
• Costs $6000 - $8000/ha

Wetting pattern in SSD irrigation

Water supply Irrigation Controller Pump Filter Mainline Submain Control valve (solenoid) Air and vacuum release valve Air and vacuum release valve Connector Drip tape (with emitters) Connector Flushing manifold Flushing valve

L a b o r a t o r y E x p e r i m e n t s P r o j e c t 1 : U n i v e r s i t y o f M e l b o u r n e F o c u s : T a r g e t e d e x p l o r a t i o n o f l i m i t i n g c r i t e r i a P r o j e c t 2 : D e p a r t m e n t o f P r i m a r y I n d u s t r i e s F o c u s : F e a s i b i l i t y i n d a i r y c o m m e r c i a l o p e r a t i o n s a n d c a t c h m e n t i m p l i c a t i o n s S c e n a r i o B u i l d i n g

G e o t e c h n i c a l F o r d i f f e r e n t s o i l s : C o m p a c t i o n b e h a v i o u r V e g e t a t i o n i m p a c t P u g g i n g t h r e s h o l d s

  

C h e m i c a l E n g i n e e r i n g W a t e r q u a l i t y t o l e r a n c e s : E m i t t e r t y p e s & c l o g g i n g F i l t r a t i o n r e q u i r e m e n t s B i o f o u l i n g L i f e s p a n & m a i n t e n a n c e

    F i e l d S t u d i e s ( D o o k i e )

I m p a c t o f w a t e r q u a l i t y a n d g r a z i n g i n t e n s i t i e s . P l o t t r i a l s , w i t h t h r e e t y p e s o f t a p e , t w o s p a c i n g s a n d t w o i n s t a l l a t i o n d e p t h s U s i n g w o r k s h o p s a n d D a i r y M o d . M o d e l l i n g s c e n a r i o s t o i d e n t i f y t h e p r a c t i c a l i t y

• f S S D i r r i g a t i o n , a n d

w h e r e t h e g r e a t e s t e c o n o m i c a a n d p r o d u c t i o n b e n e f i t s w i l l

• c c u r ( f a r m a n d

p a d d o c k s c a l e )

C a t c h m e n t s u p p o r t i n f o r m a t i o n F a r m C o n t r o l l e d E x p e r i m e n t s F a r m s c a l e i n f o r m a t i o n      

B e s t b e t d e s i g n s & v a r i a t i o n s I r r i g a t i o n s c h e d u l i n g G r a z i n g m a n a g e m e n t W a t e r u s e & p a s t u r e p r o d u c t i o n W a t e r a n d s o l u t e m o v e m e n t O t h e r e n v i r o n m e n t a l a s p e c t s

    

P r o d u c t i o n a n d w a t e r u s e W a t e r f l o w a n d s o l u t e m o d e l l i n g T h r e s h o l d i d e n t i f i c a t i o n S u c c e s s F a c t o r s E c o n o m i c a n a l y s i s

A n a l y s i s a n d M o d e l l i n g ( f a r m & c a t c h m e n t s c a l e s )  

C h a n g e s t o w a t e r a n d s o l u t e b a l a n c e s C a t c h m e n t i m p l i c a t i o n s ( w a t e r q u a l i t y a n d w a t e r m a n a g e m e n t )

 

F e a s i b i l i t y a n d b e n e f i t s A p p r o p r i a t e d e s i g n , i r r i g a t i o n s c h e d u l i n g a n d m a n a g e m e n t , g r a z i n g c r i t e r i a , f o r v a r i e t y o f s o i l t y p e s

S u b s u r f a c e d r i p i r r i g a t i o n o f g r a z e d d a i r y p a s t u r e s

O b j e c t i v e : T o e x p l o r e , e v a l u a t e a n d d e m o n s t r a t e t h e f e a s i b i l i t y a n d w i d e r b e n e f i t s o f u s i n g s u b s u r f a c e d r i p i r r i g a t i o n f o r p a s t u r e p r o d u c t i o n , a n d t o m a k e c l e a r r e c o m m e n d a t i o n s a b o u t i t s a p p l i c a b i l i t y t o t h e d a i r y i n d u s t r y

Experiment overview

• Conducted between July 2006 and June 2009
• Two sites (one “light” soil, one “medium” soil)
• Controlled experiments on commercial dairy farms

Treatments

• Three tape spacings and two irrigation frequencies
• Fertigation regime constant (apply 25 kg N/ha after each grazing)

Measurements

• Pasture production and composition
• Water use, water balances, solute movement and water quality
• Soil structure indicators, performance & longevity of SSD system

Tape installation, September 2006

~ 19 km tape at Byrneside ~ 11 km tape at Bunbartha

Head works at Bunbartha, October 2006

Experiences with pasture establishment, Byrneside (medium soil)

Wetting patterns after 30 mm of water applied, October 2006, Byrneside

0.6 0.6 m m 1.0 1.0 m 1.4 1.4 m m

1.4 m spacing, 19 Oct 2006, 9 days after irrigation started (84 mm)

1.4 m spacing, 14 Dec 2006, 65 days after watering commenced.

1.4 m spacing, 25 March 2007

Experiences with pasture establishment, Bunbartha (light soil)

1.0 m 1.4 m 0.6 m Different wetting patterns, after 185 mm water

Wetting up dilemma: spreading water vs excessive ponding

1.4 m spacing, 16 nov 2006

1.4 m spacing, 15 Dec 2006

1.4 m spacing, 05 March 2007

First grazing, December 2006/January 2007

Experiences with pasture establishment, Byrneside (medium soil)

Pasture growth for the different tape spacings, May 2007

1.4 1.4 m 1.0 1.0 m 0.6 0.6 m

Experiences with pasture establishment, Bunbartha (light soil)

0.6 0.6 m 1.0 1.0 m 1.4 1.4 m

Pasture growth for the different tape spacings, April 2007

Effects of grazing

Results 2006/07 season: Water balance 01/10/06 to 15/05/07

Et: 1052 mm P: 125 mm RO: ~0 mm D + errors: 39 mm I: 962 mm ΔS: 74 mm

Byrneside Bunbartha

P: 147 mm Et: 1074 mm RO: ~0 mm I: 1188 mm ΔS: 23 mm D + errors: 238 mm

Results 2006/07 season: Bunbartha rootzone soil moisture

50 100 150 200 250 01/10/2006 20/11/2006 09/01/2007 28/02/2007 19/04/2007 08/06/2007 moisture (mm)

Bunbartha 0.6 m Bunbartha 1.0 m Bunbartha 1.4 m ESfsl wilting point ESfsl saturation

Trouble with pump, 20 Dec to 19 Jan (affected 1.4 m bays)

Results 2007/08 season: Rootzone soil moisture (neutron probe)

50 100 150 200 250 300 01/07/2007 20/08/2007 09/10/2007 28/11/2007 17/01/2008 soil moisture in rootzone (mm)

Byr 0.6 m Bba 0.6 m Byr 1.0 m Bba 1.0 m Byr 1.4 m Bba 1.4 m Ll wilting point Ll saturation ESfsl wilting point ESfsl saturation

Irrigations commenced 17/09/07

Results: Rootzone soil moisture (Bunbartha)

1.4 m 1.0 m (4D) 0.6 m 1.0 m

Results 2006/07 season: Pasture production

1 2 3 4 5 6 7 8 9 10 15/08/2006 4/10/2006 23/11/2006 12/01/2007 3/03/2007 22/04/2007 11/06/2007 DM (t/ha) Byr - total grown Byr - total consumed Bba - total grown Bba - total consumed

Results: Pasture composition

Change in pasture composition

10 20 30 40 50 60 70 80 90 Summer 2006/07 Autumn 2007 Spring 2007 % in pasture sward (by weight) Byr ryegrass Byr clover Byr weeds Bba ryegrass Bba clover Bba weeds

Results 2006/07: Efficiency measures

1.4 m 1.0 m 0.6 m Agronomic WUEI (kg.ha-1.mm-1) 6.5 6.0 6.2 Byrneside 96 97 98 Byrneside 5.9 6.3 7.6 Bunbartha 5.2 5.6 6.8 Bunbartha 7.4 6.8 7.1 Byrneside 1.4 m 1.0 m 0.6 m Agronomic WUETW (kg.ha-1.mm-1) 92 91 90 Bunbartha 1.4 m 1.0 m 0.6 m Irrigation Efficiency (%) Tape Spacing Measure

Findings – 2006/07 season

• Subsurface drip irrigation maintained pasture production despite drought

conditions

• Subsurface drip irrigated pasture can be grazed in summer without pugging or

damage to irrigation system

• Pasture establishment and germination:

– If possible, germinate and establish pasture using rainfall – On medium soil, can use SSD irrigation to establish pasture using relatively little water – On light soils, do not use SSD irrigation for establishment (significant water loss)

• Differences in pasture production but compromised