Mladen Todorovic & Rossella Albrizio

(CIHEAM-IAMB, Italy)

Ljubomir Zivotic

(Institute for Water Management “Jaroslav

Cerni”, Belgrade, Serbia)

Deficit Irrigation of Sunflowerunder Mediterranean environmental

conditions

STREP EC 6th FPINCO-CT-2004-509087INCO-CT-2004-509087

Objectives

DIMAS overall objective:

to reduce the consumptive use of water by crops in

the Mediterranean agriculture and thereby to release

water resources for other uses

Objectives of the experiment:

to analyse sunflower growth under five water regimes

to determine critical stages of crop growth to water

deficit

to quantify the impact of water stress duration and

intensity

Sunflower characteristics

-Helianthus annuus L. hybrid Sanbro_MR

-Origin Spain

-Early flowering

-Early maturity

-Very good and good mid-late and late early vigour

-Drought and heat tolerant

-High yield potential

-Medium oil content

-Objective density 60000 per hectare

(Valenzano - BA, Southern Italy; 4103’N, 1652’E, 72 m a.s.l.)

Clay loam soil, of 70 cm depth and two layers, avg. SWC 150 mm/m

Agronomic parameters

Sowing on April 10th

Plant density 5.56 plants / m2

Harvesting on August 8th

Water regimes:

Full irrigation

Rainfed conditions

Full irrigation until the flowering and then 70% of CWR

70% of CWR during the whole season

70% of CRW until the flowering and then rainfed conditions

Measured parameters

Plant measurements (11 times during season, each 7-15 days):

-Leaf number, plant height, leaf area index, dry biomass of each plant organ (roots, stems, leaves, heads, seeds)

-FINT values obtained 6 times during a growing season (LI-COR, Light bar)

Soil characteristics:

-Depth, texture, nutrients

Climatic data:

-maximum and minimum air temperature, maximum and minimum relative humidity, solar radiation, wind speed, precipitation

Management data:

-Irrigation water volumes

Estimated parameters

Climatic data:

-reference evapotranspiration FAO P_M equation

Soil parameters:

-Water holding capacity (saturation, field capacity, wilting point), infiltration rate

Plant characteristics:

-each phenological stage (emergence, head visible, flowering, maturity) was considered to occur when it was observed in 80% of plants

-crop coefficient Kc

Management:-soil water balance and irrigation water requirements were calculated on the basis of FAO 56 Irrigation and Drainage paper

Weather data

ETo

Soildata

Crop data

ETc; Rz_SWB; IRR_net; Y/Ymax

IRR_gross

Managementdata

FAO P_MHargreaves

FAO P_M_Rs_mod

variable number of growth stages

variable application efficiency

Optional ETo method

ETomodule

Soil waterbalancemodule

Irrigationmodule

Source: Todorovic, 2006

Root zone soil water depletion for full irrigation treatment

Days after sowing

De

ple

tio

n (

mm

)

0

10

20

30

40

50

60

70

80

90

100

110

0 10 20 30 40 50 60 70 80 90 100 110 120

TAW [mm]

RAW [mm]

Depletion [mm]

8th April 8th August

F M

Days after sowing

De

ple

tio

n (

mm

)

0

10

20

30

40

50

60

70

80

90

100

110

0 10 20 30 40 50 60 70 80 90 100 110 120

TAW [mm]

RAW [mm]

Depletion [mm]

Root zone water depletion for treatment with full irrigation until flowering and then 70% of full irrigation requirements

(slight water stress)

F

M

Days after sowing

De

ple

tio

n (

mm

)

0

10

20

30

40

50

60

70

80

90

100

110

0 10 20 30 40 50 60 70 80 90 100 110 120

TAW [mm]

RAW [mm]

Depletion [mm]

Root zone water depletion for 70% of full irrigation requirements during the whole season

(moderate water stress)

F M

0

10

20

30

40

50

60

70

80

90

100

110

0 10 20 30 40 50 60 70 80 90 100 110 120

TAW [mm]

RAW [mm]

Depletion [mm]

Days after sowing

De

ple

tio

n (

mm

)

Root zone water depletion for 70% of full irrigation requirements until the flowering and then rainfed

(strong water stress)

F

M

0

10

20

30

40

50

60

70

80

90

100

110

0 10 20 30 40 50 60 70 80 90 100 110 120

TAW [mm]

RAW [mm]

Depletion [mm]

Days after sowing

De

ple

tio

n (

mm

)Root zone water depletion for rainfed treatment

F M

Irrigation date DAS Net irrigation supply (mm)

Treatment A

Treatment B

Treatment C

Treatment D

15-Apr-05 7 16.6 16.6 16.6 16.6

28-Apr-05 20 29.1 29.1 20.6 20.6

06-May-05 28 11.6 11.6 8.1 8.1

16-May-05 38 19.3 19.3 9.9 9.9

21-May-05 43 23.3 23.3 18.6 18.6

31-May-05 53 36.6 36.6 25.5 25.5

14-Jun-00 67 55.3 55.3 38.8 38.8

22-Jun-05 75 49.5 34.9 34.9 -

29-Jun-05 82 40.7 29.1 29.1 -

05-Jul-05 88 49.5 34.6 34.6 -

19-Jul-05 102 43.7 30.6 30.6 -

28-Jul-05 111 43.7 30.6 30.6 -

TOTAL (mm) 122 418.9 351.6 298.0 138.2

Irrigation Water management

Total Precipitation during growing season – 110.0 mm (at the beginning of full development, after head apperance/10 days before flowering, between flowering and maturity and one week after maturity)

Cumulative crop ET

0

50

100

150

200

250

300

350

400

450

500

0 10 20 30 40 50 60 70 80 90 100 110 120 130

Days after sowing

ET

c (

mm

)

ABCDE

AB

C

D

E

473.2456.3424.1

293.3

180.4

F

M

Seasonal variation of LAI

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

20 30 40 50 60 70 80 90 100 110 120 130

Days after sowing

LA

I

ABCDE

Flowering

3.69

2.72

1.82

FINT

0

10

20

30

40

50

60

70

80

90

100

30 40 50 60 70 80 90 100 110 120

Days after sowing

FIN

T (

%)

A

B

C

D

E

)1( LAIkePARIPAR Few days before flowering

86%

74%

FINT vs. LAI

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

LAI

FIN

T (

%)

0037.04381.00561.0 2int LAILAIF

R2=0.926

Biomass seasonal variation [t/ha]

0

2

4

6

8

10

12

14

16

18

20 30 40 50 60 70 80 90 100 110 120 130

Days after sowing

Bio

ma

ss

(th

a-1)

A

B

C

D

E

14.9

13.0

9.9

6.6

6.5

FM

YIELD [t/ha]

0

1

2

3

4

5

6

7

A B C D E

Treatments

Yie

ld (

tha-1

)

A

A

B

CC

6.14

5.42

4.22

2.10

2.07

100 100_70 70

70_0 Rainfed

Harvest index

0.41 0.42 0.43

0.32 0.32

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

A B C D ETreatments

Harv

est

ind

ex

100 100_70 70

70_0 Rainfed

0

200

400

600

800

1000

1200

1400

1600

1800

0 100 200 300 400 500 600 700 800

Cumulative IPAR (MJm-2)

Bio

mass

(gm-2

)

A1,B1 A2

B2 C1,D1

C2 D2

E1 E2

E1

A1,B1

C1,D1

E2

D2

C2

B2

A2

Biomass vs. Cumulative IPAR (two stages)

1 – pre-anthesis2 – post-anthesis

Linear regression for pre- and post-anthesis RUE

Treatment Slope (gMJ-1) R2

A1 3.88 0.99

B1 3.88 0.99

C1 3.41 0.99

D1 3.41 0.99

E1 3.43 0.94

A2 0.99 0.71

B2 0.40 0.45

C2 0.31 0.17

D2 -0.81 0.72

E2 0.82 0.39

Full irrigation

70% irrigation

Rainfed

Biomass vs. ETc (three stages)

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0 500 1000 1500 2000 2500 3000 3500 4000 4500

ETc (m3ha-1)

Bio

mas

s (

kg

ha-1

)

A1,B1 C1,D1

E1 A2,B2

C2,D2 E2

A3 B3

C3 D3

E3

E2

A3

C2,D2

A2,B2

E3

B3

C3

D3

A1-E1

1 – initial phase2 – intensive growth3 – post-anthesis

Linear regression for three stages WUE

Treatment Slope (kgm-3) R2

A1, B1 1.37 0.99

C1, D1 1.15 0.99

E1 1.32 0.97

A2, B2 7.88 0.99

C2, D2 6.79 0.99

E2 9.99 0.90

A3 1.45 0.66

B3 0.44 0.44

C3 0.39 0.13

D3 -2.38 0.67

E3 1.62 0.26

1 – initial phase2 – intensive growth3 – post-anthesis

Conclusions

Deficit irrigation (up to 70% of CWR) is an acceptable strategy for sunflower.

Importance of irrigation between head appearance through flowering up to maturity has been demonstrated.

Possible rainfed production under Southern Italy climatic conditions has been observed (early sowing, depends on rainfall distribution, initial soil water content…)

Strong correlation of irrigated water and obtained biomass and yield was observed. Translocation of assimilates is favored under mild and moderate water stress, while harvest index is strongly reduced under severe water stress.

Both RUE and WUE have shown not conservative behaviour for different water regimes

RUE should be presented as a two stages value (pre- and post-anthesis)

WUE should be presented as a three stage value (initial, pre- and post-anthesis)

Acknowledgements:

•EC 6TH Framework Programme (INCO-MED)

•DIMAS Partners

•IAMB Technical staff: Mr. C. Ranieri, Mr. R. Laricchia, Mr. A. Divella,

…

Thank you