La fertilisation de l`amandier

Transcription

Climate Change and Nut
Crops Vulnerability in the
Mediterranean Arid Areas
M. Ghrab,
M. Ben Mimoun, M. Masmoudi, N. Ben Mechlia
Institut de l’Olivier, Sfax, Tunisie
Institut National Agronomique de Tunisie
XVI GREMPA
FAOFAO-CIHEAM NETWORK
ON NUTS
Meknes, May 2015
Almond
- Second crop (200000 ha)
- Important genetic diversity
- Rainfed conditions (94%)
20%
10%
- Irrigated area 6%
70%
60%
Pistachio
- More than 40.000 ha
- Main cultivar Mateur
- Rain-fed conditions
- Arid and semi arid climate
- Irrigated area 4%
30%
10%
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Almond and Pistachio crops are vulnerable to
temperature fluctuations and decreasing water
availability.
Yield response of almond and pistachio to global
warming is evaluated under the arid conditions.
The approach is focussing on chilling and its
incidence on yield, using various chilling models.
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Production zone: Sfax regions as the main almond
production zone.
Trends in Winter Chill and precipitation based on
35 years of daily climatic data (1980-2014).
Three Chilling Models were used:
- Crossa-Raynaud method as chilling hours (CHCR)
- Utah Model as Chill unit (CU)
- Dynamic Model as chilling portions (CP)
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Almond
- Four cultivars Fekhfekh, Ferragnes, Ferraduel and Tuono
from the national almond collection were considered
- Rainfed conditions with no fertilisation
- Survey 2001-2013
- Flowering period and Yield
Pistachio
- Main cultivar Mateur
- Rain-fed conditions
- Survey 1997-2013
- Flowering and Yield
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Chilling Trends
CHCR
80
CU
CP
900
60
600
40
300
20
0
0
1975
Chillig Portions (CP)
Chilling Hours (CHCR), Chill Unit (CU)
1200
1980
1985
1990
1995
2000
2005
2010
2015
Declining trend in winter chill using three models.
Warm winters becomming more frequent (3-4 years).
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250
Precipitation Variability
Deviation from mean
200
150
100
50
0
-50
-100
-150
-200
High variability in annual precipitations with decreasing tendency.
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Climate Variability
Observed increases in temperature and precipitation
variability, induced by global warming, are expected to
have harmful effects on fruit trees, particulary in
rainfed agro-systems.
Almond and pistachio trees are increasingly subjected to
lack of chilling, since warm winters are becoming more
frequent (1997, 2001, 2007, 2010, 2013).
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Flowering and Yield of Almond vs.
Winter chill
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Flowering date (DOY)
80
Fakhfekh
Fgnes-Fduel
60
Tuono
40
20
0
0
100
200
300
400
500
Chilling hours (CHCR)
Flowering date of Almond was related to Winter Chilling.
Severe lack of chilling delays the flowering date (15 days for
Fekhfekh).
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During exceptional warm years (2007 and 2010), increases
of flower buds fail and physiological disorder (double and
triple fruits) occured mainly for Tuono cultivar.
Flower bud fail
Double fruits
Fekhfekh
7.2
10.3
Fduel-Fgnes
11.4
29.6
Tuono
25.7
67.4
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30
Tuono
Yield (Kg tree-1)
Fekhfekh
Fduel-Fgnes
20
10
0
50
150
250
350
Yields of three almond cultivars varied within similar ranges
but seemed to be less affected by warm winters, whereas
one variety (Tuono) seemed to be high sensitive to rainfall
variations.
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Flowering and Yield of Pistachio vs.
Winter chill
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Flowering date (DOY)
130
R² = 0.60
120
110
100
90
80
0
100
200
300
400
Chilling hours (CH)
The beginning of flowering of pistachio was found to be highly
related to winter thermal regimes. The severe lack of chilling
delays the flowering by about one month.
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Pistachio yields varied between 0 and 35 Kg per tree over
the monitoring period (1997-2013),
The yearly variations of pistachio yields are closely
related
to
climatic
conditions.
A
positive
correlation
between nut yield and winter chill accumulation was
obtained.
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Nut yield (Kg tree-1)
30
R² = 0.42
20
10
0
50
150
250
350
An exponential increase of nut yield with winter chill accumulation
until reaching the chilling requirement. After that nut yield seemed
to be unaffected by chilling but rather by precipitation.
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CONCLUSION

Analysis of climatic data revealed
important decline in winter chill in
Central Tunisia.

Warm winters impacted strongly yields
of the pistachio crop cv. Mateur, but
only within some limits those of three
almond cultivars.

Tuono appeared to be more sensitive
to drought.

It will be interesting to consider the
important genetic diversity to mitigate
the harmful effect of global warming.
THANK You
For your
Attention