Download Annex N Sunflowers and Climate Change

Sunflowers and Climate Change
1
SUMMARY
Global temperatures have been rising over the past 25 years by approximately 0.2°C per
decade and this has been attributed to an increase in greenhouse gas emissions. The main
sources of these gases and aerosols are burning of fossil fuels for energy supply, transport and
industry, with an increasing amount coming from residential and commercial, forestry and
agriculture. Central England temperatures have seen a 1ºC rise during the twentieth century,
whilst the occurrence of hot summer days (>25ºC) almost doubled during the first half of the 20th
century. The UK Climate Impacts Programme (UKCIP) was set up by Defra in 1997 to provide a
research framework for the integrated assessment of climate change impacts in the UK. An
updated set of climate change scenarios for the UK were produced in 2002 and it is these that
have been used in this report. The principle factor determining the rate of physiological
development in sunflower is the accumulated air temperature (mean daily air temperature over
a 6°C). The projections from UKCIP02 data indicate that the area suitable for sunflower
production will increase to approximately 79% of the land area of England by 2050. There will
be a substantial increase in the number of varieties that will be suitable for use in the UK.
Rainfall levels will decrease but this will suit the drought tolerant nature of sunflowers. Diseases
currently experienced such as sclerotinia and verticillium wilt may become more important and
botrytis less important in future. Phomopsis and phoma are also likely to become more
prevalent.
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INTRODUCTION
The climate of the British Isles and the world is already changing. According to the latest and
fourth assessment (4AR) of the International Panel on Climate Change (IPCC)
‘warming of the climate system is unequivocal, as in now evident from observations in global
average air and ocean temperatures, widespread melting of snow and ice, and rising global
temperatures’ (IPCC, 2007, 1).
The global mean average temperature has increased 0.74ºC (+/-0.19 ºC) between 1906 to
2005, and over the past 25 years has been rising at about 0.2 ºC per decade (+/-0.05 ºC)
(IPCC, 2007, Jenkins et al., 2007). Furthermore, 11 of the last 12 years (1995 to 2006) rank
among twelve of the warmest in the instrumental record of global surface temperature since
1850. Rising global sea levels are also consistent with global warming- global sea level has
been increasing at an average rate of 1.8 mm/yr since 1961 and at 3.1 mm /yr (+/-0.7mm /yr)
since 1993 (IPCC 2007). Other evidence of global climate change include the reduction in the
extent of sea ice, with satellite studies showing the average annual Arctic sea ice extent
decreasing by 2.7% per decade (IPCC, 2007).
2.1
Drivers of Climate Change
Climate change arises from variations in the energy balance of the earth. The earth receives its
energy from the sun in the form of short wave radiation. This energy passes relatively easily
through the atmosphere and is absorbed by the earth and re-emitted as long wave energy.
Some of this long wave energy escapes out to space, whilst some is trapped by greenhouse
gases. These gases, keep our earth’s temperature 30 ºC warmer than it otherwise would be.
Both changes to the amount of solar radiation entering the atmospheric system and the amount
of greenhouse gases in the atmosphere can cause climate change.
The causes of climatic change are natural. For example, changes in solar activity, the orbit of
the earth around the sun or natural oscillations within the climate system such as the North
Atlantic Oscillation or El Nino Southern Oscillation (ENSO). Volcanic eruptions are also an
important driver of natural climate change. These changes have occurred throughout the earth’s
history, and have resulted in cooler and warmer periods such as the Little Ice Age and the
Medieval Warm Period. Anthropogenic or human induced changes on the climate arise from
1
activities that increase the concentrations of greenhouse gases and aerosols in the earth’s
atmosphere, preventing long wave radiation from escaping to space and thereby cause
anthropogenic ‘global warming’.
The current observed warming of the earth’s global climate is happening at a much faster rate
than previously experienced in history. The recent global climate models show that the current
warming trend cannot be explained by natural variations alone and that for the models to agree
with current observations, anthropogenic effects must be included (Hulme et al., 2002, IPCC
2007, Jenkins et al., 2007).
It is very likely (>90% probability) that the main cause of the recent observed global climate
changes is an increase in anthropogenic Greenhouse Gas emissions (IPCC, 2007). The Fourth
Assessment Report (4AR) from the IPCC states that between 1970 and 2004 there has been a
70% increase in anthropogenic Greenhouse Gases. The main sources of these gases and
aerosols are burning of fossil fuels for energy supply, transport and industry. Residential and
commercial, forestry and agriculture have also increased as a source of Greenhouse Gases, but
at a much slower rate.
Different Greenhouse Gases and aerosols have different radiative properties and lifetimes in the
atmosphere and therefore varying warming effects. The most important anthropogenic
Greenhouse Gas is Carbon Dioxide, which is very long lived (100 year life span) and is mainly a
consequence of burning fossil fuels and to a lesser extent land use (e.g. deforestation). Carbon
Dioxide concentrations have increased by 80% between 1970 and 2004. Pre industrial levels of
Carbon Dioxide were 280 ppm but by 2005 reached a level of 379 ppm (IPCC 2007).
Methane, nitrous oxide and halocarbons are also important and long lived Greenhouse Gases.
The main anthropogenic source of methane is agriculture and land use whilst nitrous oxide is
mainly from agriculture. Methane has increased from 715 ppb pre industrial levels to 1774 ppb
in 2005 (4AR, IPCC 2007). Nitrous oxide has increased from 270 ppb to 319 ppb in 2005 (4AR,
IPCC 2007). Agriculture is therefore affected by and contributing to climate change.
2.2
Observed Climate Change
We do not have to look back very far in our recent climate history to understand the impact of
climate change on agriculture and our society as a whole in the UK. For example, the hot
summer of 2003, the floods of autumn 2000 and summer 2007. The UK climate has changed
over the 20th Century, which is consistent with the warming in global climate (Hulme et al.,
2002). Some of the headline messages for the UK published by UKCIP are summarised in the
Table below.
Some of the main points are as follows:
•
Central England temperatures have seen a 1ºC rise during the twentieth century, whilst the
occurrence of hot summer days (>25ºC) almost doubled during the first half of the 20th
century (IPCC 2007). August 2003 saw the hottest maximum temperature ever recorded in
the UK, 38.5 ºC in Faversham, Kent.
•
Air frosts have been declining in frequency
•
Predictions suggest that the UK will continue to get warmer with summers being hotter and
drier
•
Winters have been getting wetter and there is a larger proportion of heavy rainfall events
throughout the year (Hulme et al., 2000).
•
Winters will continue to get milder and wetter.
2
Table 1 Summary of UK Predicted and Observed Climate Changes (source: Hulme et al., 2002,
Jenkins et al., 2007, Perry 2006).
Climate
variable
UK Observations (Jenkins et
al 2007, Hulme et al 2002 and
Perry 2006)
UK Predictions (UKCIP 02)
Average
Annual
Temperature
Regions of the UK have seen a
significant rise between 0.47 and
1.18 ºC between 1916 and 2006.
Since 1961 and 2006 all regions
have seen a significant increase
between 1.05 and 1.67 ºC.
By 2040 an increase of 0.5 and 1 ºC and by 2100 an
increase of 1 and 5 ºC. (High confidence)
Average
Summer
Temperatures
Increased between 0.55 and
1.02 ºC between 1916 and 2006
and between 1.24 and 1.9 ºC
since 1961
By 2040 expected to increase by 0.5 to 2 ºC depending
on region. By 2100 rises between 1 and 6 ºC expected
depending on region and scenario (High confidence).
Summer Heat
waves
Average duration of summer
heat waves has increased in all
regions between 4 and 16 days
since 1961 (UKCIP 02)
Number of very hot days expected to increase, with high
temperatures similar to August 2003 or July 2006 (>3 ºC
above average) predicted to be more frequent under low
emissions scenario (medium confidence)
Average
Winter
Temperatures
Increased significantly since
1961 by between 1.22 and 2.02
ºC across the UK.
Expected to increase between 0.5 and 1 ºC by 2040 and
between 1 and 4 by 2100 (high confidence)
Temperature
extremes
Warming will be greater in SE compared to NW (high
confidence) and greater for summer and autumn than
winter and spring (Medium confidence).
Number of very hot days increases, especially in
Summer and Autumn (high confidence)
Heating
Degree Days
Heating degree days across UK
regions have decreased by 12 to
18% between 1961 and 2006.
Decrease across the UK (high confidence)
Air Frost
Days of air frost have decreased
by between 19 and 28 days
across UK regions between
1961 and 2006
Expected to decrease (high confidence)
Cooling
Degree Days
Change between 2.5 and 32.3
days between 1961 and 2006
over the UK
Increase everywhere across the UK (high confidence)
Thermal
Growing
Season
Increased by up to 30 days since
1900
Season will continue to lengthen, with largest increases
in the SE (high confidence)
Soil Moisture
Content
Annual
Precipitation
Soil moisture contents in summer and autumn are
expected to decrease (high confidence)
Not changed significantly since
records began in 1766 with high
inter annual variability; except for
3
Climate
variable
UK Observations (Jenkins et
al 2007, Hulme et al 2002 and
Perry 2006)
UK Predictions (UKCIP 02)
Scotland which has seen an
increase by up to 23%.
Summer
Rainfall
Decreased in most regions by up
to 16.7% - although not all
regions see a decrease or a
significant trend. Small decrease
in contribution of heavy rainfall
days for some region by up to
1.8 days but not significant.
By 2100, up to 50% reduction depending on scenario
and region (medium confidence)
Winter
Rainfall
All regions have shown an
increase in winter rainfall since
1961, varying between 11 and
66%. Small increase in the
contribution of heavy rainfall
days (> 1mm) by between 1.4
and 8.6 days, but not significant.
By 2100, up to 30% increase depending on scenario
and region (high confidence) i.e. wetter winters
Precipitation
Intensity
Increases in winter (high confidence)
Snowfall
Number of days with >50% snow
cover has decreased by between
3.5 and 18.6 days between
1961/2 and 2004/5 (Perry, 2006)
Snowfall amounts expected to decrease (high
confidence) and many regions will have no snow for
multiple winters (low confidence)
Storminess
Severe wind storms around the
UK have become more frequent
in last few decades, although not
as stormy as 1920’s. Windiest
periods coincide with positive
NAO index.
Winter depressions
confidence)
Relative
Humidity
Annual relative humidity values
across the UK have seen a
decrease between 0.8 and 4.3%
between 1961 and 2006.
Specific humidity increases throughout the year (high
confidence). Relative humidity decreases in summer
(medium confidence)
Sea Level
Pressure
Annual changes in sea level
pressure have been small and
not significant between 1961 and
2006 across the UK.
Sea Surface
Temperatures
Increased over the last 30 years
by 0.7 ºC around UK
Sea surface temperatures expected to increase but not
as rapidly as air temperatures (high confidence)
Sea Level
Increase of 1mm/yr in 20
Century, corrected for land
movement and even higher in
the last few decades.
th
Extreme sea levels are expected to occur more
frequently and by 2100 storm surge events could occur
20 times more for some coastal locations (medium
confidence)
become
more
frequent
(low
Significance level refers to 95% significance level in the table. Period trend analyses is conducted on is
1961 to 2006 unless otherwise stated.
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3
BACKGROUND TO CLIMATE CHANGE SCENARIOS
Climate change scenarios are plausible descriptions of how things may change in the future
(Hulme et al., 2002). The UK Climate Impacts Programme (UKCIP) was set up by Defra in 1997
to provide a research framework for the integrated assessment of climate change impacts in the
UK (Holman et al., 2007). The first climate change scenarios were released in 1998 (UKCIP98)
as documented in Hulme and Jenkins (1998). In 2002, UKCIP published a new set of climate
change scenarios for the UK, which were based on the Met office Hadley Centre global climate
models, and a Regional Climate Model (RCM) which allowed the projections to be downscaled
over Europe to give greater spatial detail at 5km (Hulme et al., 2002). The UKCIP02 scenarios
are the most up to date scenarios available to the research community at this time.
It was hoped that UKCIP 08 data, the fifth generation of UK climate change scenarios, would be
available for this project. However, due to a delay in the release of the data, the now called
UKCIP 09 data is not available for this work. The advantage of the UKCIP 09 data over the
UKCIP 02 data is the provision of probabilistic climate projections, which provide greater
understanding of the uncertainties associated with the modelling outputs. For further information
on the UKCIP 09 data, please refer to http://www.ukcip.org.uk/.
As a result, this study uses UKCIP02 scenarios. The UKCIP02 scenarios are averaged over 30
year periods centred on the 2020’s, 2050’s, and 2080’s. There are four emission scenarios
which take into account variation in demographic, economic and technological driving forces
that result in different Greenhouse Gas emissions, as summarised in the Table below. The low,
medium-low, medium high and high scenarios are based on the global emission scenarios from
the IPCC Special Report on Emission Scenarios (SRES, 2000). The scenarios predict increases
of global Greenhouse Gas emissions of between 25-90% (CO2 equivalent), for the period 2000
and 2030. Note that typically the 1961-1990 climate period is used as the comparison baseline
for the scenario predictions and that for the 2020s scenarios, predicted climate changes are
similar for all scenarios because they are linked to our past emissions to which we are
committed due to inertia in the climate system (Hulme et al., 2002).
Table 2 Summary of the UKCIP 02 Emission Scenarios (adapted from UKCIP 2008, Glynn 2008)
SRES
UKCIP02
Description
A1F1
High
Emission
s
Rapid economic growth, global population peak
mid century and then declines, rapid introduction
of new technologies but continued reliance on
fossil fuels.
3.9
810
A2
MediumHigh
Emission
s
A heterogeneous world with high population
growth. Regional focus to economic development
and local identity remains strong. Technological
change is slower and more fragmented than
other scenarios.
3.3
562
B2
Medium
Low
emissions
An intermediate population and economic growth
rate with local solutions to economic, social and
environmental sustainability. Technological
change is less rapid and less diverse than in high
and low scenario.
2.3
562
B1
Low
emissions
A convergent world with regional and global
solutions to economic, social and environmental
sustainability. Global population as in high
emissions scenario but with rapid changes in
economic structures towards a service and
2.0
525
Mean Global
Temperature
(C) in 2080s
5
Atmospheric CO2
Concentration
(ppm) in 2080s
information economy and introduction to clean
and resource efficient technologies
There are a number of uncertainties associated with future climate change scenarios and
specifically the UKCIP02 predictions. These uncertainties must be considered when assessing
climate change impacts and risks (Arkell et al., 2007, Hulme et al., 2002). The main
uncertainties associated with the UKCIP02 predictions are summarised below.
Table 3 Uncertainties associated with climate change scenarios (based on UKCIP (2008b)
Uncertainty
Description
Emissions
Emissions used in the climate models are estimated and depend on future population and
world technological development. A range of emissions from low to high is provided to
mitigate this uncertainty.
Model
Although the models used to generate the climate change scenarios are the best available
in the world, they do not allow a full quantitative description of climate sensitivity and not all
climate feedbacks are fully understood and represented in the models (e.g. North Atlantic
Drift). Various models handle different climate processes differently and is the reason why
UKCIP 08 will use ensemble predictions to quantify this uncertainty.
Natural
climatic
variability
The natural variability in the climate system cannot yet be modelled, and neither can the
climate feedbacks. This means that the uncertainty in extreme events is greater than
seasonal or annual means, as the uncertainty in the longer term trends is less.
Impacts
There is also some uncertainty in the impacts that climate change will have on different
sectors- based on current understanding and do not account for future policies.
UKCIP 02 scenarios provide useful information on long term average climate changes, but do
not give much indication for extreme events. Vulnerability to climate change is often determined
by the frequency and magnitude of extreme events.
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DATA
4.1
1971-2000 Climatology
To understand the current climate for growing sunflowers in the UK, data from the Met Office
1971-2000 climatology and the Met Office Agricultural Land Classification (ALC) 1971-2000
climatology has been used. The 1971-2000 Met Office climatological database is the most
recent official 30 year climatology available.
The following parameters, which are important for sunflower growing in the UK, have been
summarised.
•
Mean monthly 30 cm soil temperatures for April and May, to estimate soil temperatures
on 1st May (ALC 1 km database)
•
Mean accumulated air temperatures above 6 ºC. This parameter is estimated from the
1971-2000 mean maximum and minimum temperatures (Met Office 5 km database).
•
Mean monthly rainfall rate (mm/ month) (ALC 1km database).
•
Mean monthly number of rain days (>0.2 mm per day) and wet days (>1.0 mm per day)
(Met Office 5 km database).
4.2
Climate Change Data
The UKCIP 02 medium-high scenarios are used to represent the future climate of the UK in the
2020’s and 2050’s. The UKCIP parameters used in the study were as follows:
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Accumulated temperatures above 6 ºC, estimated from the UKCIP02 mean temperatures at
5km resolution
• Mean monthly rainfall rate (mm /month) at 5 km resolution
Unfortunately, there are no soil temperatures available in the UKCIP02 database, and there are
no known methods for estimating soil temperatures from the available parameters.
Furthermore, wet and rain days are not available parameters in the scenarios.
•
5
RESULTS
A review of UK sunflower production completed in 1998 (Cook et al.,, 1998) identified the
parameters for successful sunflower production. Soil type, fertility and lack of water were
unlikely to be limiting. There were two major constraints on production:
1. The period available for production determined by the earliest date on which sowing
was practicable (minimum soil temperature)
2. the latest date at which maturity is completed and harvesting can no longer be delayed
(accumulated air temperature)
5.1
Soil temperature
Sunflowers are drilled when soil temperatures at 5 cm are 6-8 °C, which usually occurs between
mid-April and mid-May in the UK. This is approximately equivalent to the soil temperature of 10
°C at 30 cm. Temperatures at 30 cm give a greater degree of consistency than at the soil
surface.
The mean soil temperature at 30 cm for the 1st May, was derived from the Met Office
Agricultural Land Classification dataset at a resolution of 1 km. As only monthly values are
available, the mean soil temperature on the 1st May was estimated by taking the mean of April
and May soil temperatures.
Soil temperatures in excess of 10 °C are found in a broad area to the south of a line from the
Wash to the Severn estuary. Values greater than 10°C can also be found in small areas along
the Welsh coast, parts of Shropshire and around the Wirral (Figure 1).
No soil temperatures are available in the UKCIP02 database but it could be concluded that with
the rise in air temperature that soil temperatures would rise similarly (Harrison and Butterfield,
1996). Sunflowers would then be able to be sown earlier and on a greater area than currently
suitable.
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Figure 1 Mean soil temperature at 30 cm on 1 May (1971-2000 data).
5.2
Accumulated air temperature
Accumulated air temperature (mean daily air temperature over a base value) is the principal
factor determining the rate of physiological development in sunflower. The base value for
sunflower is 6 °C (Hutley-Bull, unpublished) the same as for maize.
For both the observed 1971-2000 climatology and the UKCIP 02 climate projections, the mean
accumulated air temperatures (measured in Degree Celsius Days above 6 ºC), were estimated
from the gridded mean temperatures. For the UKCIP 02 scenarios, the mean monthly
temperatures were provided. For the Met Office 1971-2000 climatology, mean monthly
temperatures were estimated from mean of the minimum and maximum monthly temperatures.
The relationship between mean monthly temperatures and daily mean accumulated
temperatures above a base of 6 ºC was derived from observed daily data. Eight meteorological
stations, representative of geographically diverse areas of the UK, were chosen to derive the
regression relationship. The monthly accumulated temperatures above 6ºC were calculated for
each station, for the period 1980 to 1995. The mean monthly temperatures were calculated from
the 1971-2000 air temperatures for each of the stations.
A regression analysis between the monthly accumulated temperatures and the monthly
temperatures was performed for April to October, since these are the months which are
important for growing sunflowers. A strong relationship with a R2 of 0.995 was found. The
relationship, as stated in equation 1, was subsequently applied to the 5km gridded mean
monthly temperatures in the 1971-2000 and UKCIP 2020 and 2050 scenarios.
Act = (0.9363 * Tave)- 4.9324) * No. of Days in Month
Where; Act = Monthly Mean accumulated temperature above 6C (°C days)
8
(eq 1)
Tave= Monthly mean temperature
A total of 1400 ºC days heat input is the minimum needed to produce a crop of semi-dwarf
sunflower defined by CETIOM as très précoce which are the type of sunflower grown in the UK.
In order to achieve a total of 1400 ºC days during most years, the seasonal mean value would
have to be higher. From statistical tables it is calculated that to exceed the thermal sum
threshold during nine years out of ten, the mean value would have to be 1.282 standard
deviations greater. The standard deviation of the seasonal totals from the Met Office sites was
100 ºC days. This gives a required mean total of 1400 + 1.282 (100) = 1528 °C days.
Three seasonal periods were assessed (a) May to October (b) May to September (c) April to
September. The seasonal values were calculated by summing the monthly mean accumulated
temperatures above 6 ºC (°C days) for the relevant months. These scenarios must be
considered in relation to the suitability of sunflowers within local rotations and cropping patterns,
where low soil temperatures discourage early drilling and where severe frosts in October make
harvesting impracticable.
Currently sunflowers are drilled early May when soil temperatures reach threshold and
harvested in early October when mature. Production outside this period can occur but very
rarely. The past 2 seasons, 2007 and 2008, have been very poor for sunflower production in the
UK due to high rainfall and low temperatures. The area suitable for sunflower production based
on accumulated air temperature is shown in Figure 2 and is limited to an area south of a line
drawn between the Wash and the Severn and accounts for approximately 22% of England. The
UKCIP scenarios for 2020 (Figure 3) and 2050 (Figure 4) indicate sunflowers could be grown
successfully, in England, south of the Humber and into north east Yorkshire, accounting for 50%
of the area by 2020 and 79% by 2050.
With the increase in temperatures the varieties currently grown (semi-dwarf types) would mature
earlier bringing harvest forward to September, currently this is rarely achieved (Figure 5) but
would be more likely in 2020 and 2050 (Figure 6 and Figure 7). The likely outcome of
temperature increases would bring drilling dates forward to April and harvest to September;
currently this is not a viable option except for small areas of southern UK (Figure 8). In 2020 the
area suited to production becomes more widespread south of the line between the Wash and
the Severn (Figure 9). By 2050 the area suited for production is south of the Humber and
including NE Yorkshire (Figure 10). It would be likely that the current vary early sunflower
varieties would be grown in the northern areas possibly using a later drilling date whilst the
increasing temperatures would enable southern UK growers to grow a wider range of early, midseason and possibly late varieties as now grown in France (CETIOM, 2008). Varieties with
resistance to disease and different oil profiles will be available to UK growers.
Successful harvest of sunflowers could be routine during August and September under the
projections for 2020 and 2050.
5.3
Rainfall
Sunflower can produce reasonable yields where rainfall is as low as 420 mm per annum and
much depends on the seasonal distribution, the crop primarily needing moist conditions for
establishment. The crop is most responsive to irrigation as the flower bud forms through to
early maturity as the back of the heads turn yellow. CETIOM (2008) advise that 30-100mm of
water at this time will be sufficient but this depends soil water reserves and the state of the crop.
Too much irrigation can make crops lush and more susceptible to disease.
Projections for rainfall (Figure 11, Figure 12 and Figure 13) indicate less rainfall over the UK
which would suit the crop more so than current spring crop alternatives. Irrigation may have to
be applied at the susceptible growth stages.
9
5.4
Disease implications
In 2020 and 2050 sowing date could have moved back into April, temperatures and therefore
seedling disease problems will therefore be similar to the current situation. Many soil-borne
pathogens are active above specific temperature thresholds, but also require adequate soil
moisture (Smith and Gladders, 2009). The main periods of activity can therefore be defined.
Sclerotinia’s apothecial activity could extend throughout the year with a 2ºC temperature rise.
Whilst higher temperatures are expected to increase disease severity, the more critical factor is
likely to be rainfall distribution. Soils must be moist for several days for sclerotia of S.
sclerotiorum to germinate and produce apothecia. This must continue for a further period to
allow ascospore production and dispersal. However, periods of several weeks without rainfall do
not necessarily stop sclerotinia activity, as noted in April 2007 when sclerotia germinated in soil
cracks or from moist soil several centimeters below the soil surface (Gladders et al., 2008). Dry
soils in summer and high temperatures could inhibit spore production, with temperatures >26ºC
also inhibiting ascospore infection (Koch et al., 2006). Under climate change, there may be
changes in the strains of S. scleriotiorum that affect crops, if some types are adapted to higher
temperature conditions. Rainfall is expected to be less frequent, but be more intense. Infection
events are expected to occur, but may be less numerous than at present in summer. Infections
that do occur may develop more rapidly. On sunflower the damage caused early in the season
may increase, whilst late season infection is decreased by high temperatures.
In contrast to sclerotinia being dependent on moist soils and days with rainfall, verticillium wilt is
likely to be more damaging when summer temperatures are higher and crops are under
moisture stress. Host infection requires moist soils and soil temperatures above 15ºC.
Thereafter, the disease has a soil temperature optimum of 24ºC (Schnathorst, 1981) and would
be more damaging when rainfall was low.
Botrytis has been most damaging when it caused severe head rot on late harvested crops.
Under climate change, the adoption of early maturing varieties and completion of harvest during
September should reduce the severity of attacks. Again, rainfall distribution will be influential as
heavy rain over 2-3 day periods is likely to sufficient for sporulation, infection and lesion
development to occur.
It appears likely that sclerotinia and verticillium wilt may become more important and botrytis
less important in future. As the changing climate will resemble parts of northern and eastern
France, other diseases such as Phomopsis and Phoma are likely to become more important.
Care must be taken with choice of varieties, crop rotations and avoidance of irrigation at full
flower to ensure that future disease risks are managed.
6
CONCLUSIONS
•
UKCIP projections for 2050 indicate that the area suitable for sunflower production in the UK will
increase to approximately 79% of the land area of the UK.
•
Decreasing rainfall levels will suit the drought tolerant nature of sunflowers.
•
Diseases currently experienced such as sclerotinia and verticillium wilt may become more
important and botrytis less important in future.
•
Phomopsis and phoma are also likely to become more prevalent in crops.
10
Figure 2 Average Accumulated
Temperatures 1971-2000 (B) May to
October (6 months)
11
Figure 3 Average Accumulated
Temperatures 2050’s Scenario (B) May to
October
Figure 4 Average Accumulated Temperatures
2050’s Scenario (B) May to October
Figure 5 Average Accumulated
Temperatures 1971-2000 (A) May to
September (5 months)
12
Figure 6 Average Accumulated
Temperatures 2020’s Scenario (A) May to
September
Figure 7 Average Accumulated
Temperatures 2050’s Scenario (A) May to
September
Figure 8 Average Accumulated
Temperatures 1971-2000 (C) April to
September (6 months)
13
Figure 9 Average Accumulated
Temperatures 2020’s Scenario (C) April to
September
Figure 10 Average Accumulated
Temperatures 2050’s Scenario (C) April to
September
Figure 11 1971- 2000
Figure 12 2020’s Medium-High Scenario
14
Figure 13 2050’s Medium-High Scenario
© Crown Copyright 2002. The UKCIP02 Climate Scenario data have been made available by
the Department for Environment, Food and Rural Affairs (Defra). Defra accepts no responsibility
for any inaccuracies or omissions in the data nor for any loss or damage directly or indirectly
caused to any person or body by reason of, or arising out of any use of, this data
7
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Written by Sarah Cook, ADAS UK Ltd. [email protected]
This document was funded through the Defra Innovation
Network, led by the University of Warwick
(www.warwick.ac.uk/go/climatechange/innovation-network), G B
seeds Ltd (www.gbseeds.co.uk) and HGCA (www.hgca.com) .
January 2009
For more information visit:
http://www.hgca.com/content.output/3308/3308/Crop%20Research/Crop%20Research/Sunflowers.mspx
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