Mladen Todorovic

1
Deficit Irrigation of Sunflowerunder
Mediterranean environmental conditions
STREP EC 6th FP INCO-CT-2004-509087

• Mladen Todorovic Rossella Albrizio
• (CIHEAM-IAMB, Italy)
• Ljubomir Zivotic
• (Institute for Water Management Jaroslav Cerni,
  Belgrade, Serbia)

2
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

3
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

4
(Valenzano - BA, Southern Italy 41?03N,
16?52E, 72 m a.s.l.)
Clay loam soil, of 70 cm depth and two layers,
avg. SWC 150 mm/m
5
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

6
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

7
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

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Weather data
ETo module
Optional ETo method
FAO P_M Hargreaves FAO P_M_Rs_mod
ETo
Soil data
Crop data
Soil water balance module
ETc Rz_SWB IRR_net Y/Ymax
variable number of growth stages
Management data
Irrigation module
IRR_gross
variable application efficiency
Source Todorovic, 2006
9
Root zone soil water depletion for full
irrigation treatment
F
M
Days after sowing
8th April
8th August
Depletion (mm)
10
Root zone water depletion for treatment with full
irrigation until flowering and then 70 of full
irrigation requirements (slight water stress)
F
Days after sowing
M
Depletion (mm)
11
Root zone water depletion for 70 of full
irrigation requirements during the whole
season(moderate water stress)
Days after sowing
F
M
Depletion (mm)
12
Root zone water depletion for 70 of full
irrigation requirements until the flowering and
then rainfed(strong water stress)
Days after sowing
F
Depletion (mm)
M
13
Root zone water depletion for rainfed treatment
Days after sowing
Depletion (mm)
F
M
14
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)
15
Cumulative crop ET
M
473.2
A
B
456.3
F
C
424.1
293.3
D
180.4
E
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Seasonal variation of LAI
Flowering
3.69
2.72
1.82
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FINT
Few days before flowering
86
74
18
FINT vs. LAI
R20.926
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Biomass seasonal variation t/ha
M
F
14.9
13.0
9.9
6.6
6.5
20
YIELD t/ha
6.14
5.42
A
A
4.22
B
2.10
2.07
C
C
70_0
Rainfed
100
70
100_70
21
Harvest index
70_0
Rainfed
100
70
100_70
22
Biomass vs. Cumulative IPAR (two stages)
1 pre-anthesis 2 post-anthesis
A2
B2
C2
A1,B1
D2
E2
E1
C1,D1
23
Linear regression for pre- and post-anthesis RUE
Full irrigation
70 irrigation
Rainfed
24
Biomass vs. ETc (three stages)
1 initial phase 2 intensive growth 3
post-anthesis
A3
B3
C3
A2,B2
E3
D3
E2
C2,D2
A1-E1
25
Linear regression for three stages WUE
1 initial phase 2 intensive growth 3
post-anthesis
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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)

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Acknowledgements

• EC 6TH Framework Programme (INCO-MED)
• DIMAS Partners
• IAMB Technical staff Mr. C. Ranieri, Mr. R.
  Laricchia, Mr. A. Divella,

Thank you