Climate change is projected to significantly impact soybean production in Western Brazil through increased temperatures, altered precipitation patterns, and more extreme weather. By 2080 under a business-as-usual scenario, average temperatures are expected to rise 3-4°C and precipitation may decrease by up to 40% in Western regions. This will likely reduce soybean yields substantially and have large economic consequences given the importance of soybean agriculture. Adaptation strategies like improved water use efficiency, developing heat-tolerant soybean varieties, integrated pest management, and modified farming practices will be needed to sustain soybean production under future climate conditions.

1. The Impact of climate change on Soybean production and farming
systems in Western Brazil
With the world population on the rise and the impacts of climate change set to become
more prevalent, it has become of crucial importance to study the impacts of climate
changes on crop yields. Tropical areas especially can be quite vulnerable to climate change.
In Brazil, agriculture is such an important industry as they are one of the largest exporters of
a range of arable goods, with agriculture accounting for over 30% of GDP (Marengo et al.,
2010). Since Brazil is a large country, the impacts of climate change are likely to vary among
the regions. Therefore, the focus of this essay will be on the Western regions (such as Mato
Grosso, Western Amazonia) as it’s predicted that these areas are likely to be quite affected
under a 2080 temperature & precipitation A2 scenario. Also, an emphasis will be placed on
the effects on soybean crops, which is arguably one of Brazil’s most valuable crops and
hence yield changes in this crop are likely to impose a very high economic impact on
Brazilian agribusiness.
In order to tackle these issues, it is necessary to establish climate change estimates for the
worst case scenarios, as to aid farmers with adaptive solutions in order to help sustain crop
yields under any situation.
Future projectedclimate changes
Average temperatures
Figure 1: Change in average annual temperature by 2100 (A2 business as usual scenario)
(Meteorological Office, 2012)

2. Figure 2 – Percentage change in average annual precipitation by 2100 (A2 business as
usual scenario) (Meteorological Office, 2012)
Figure 1 shows that average temperatures are set to increase by at least 3.5oc throughout
Brazil, with increases of 3.5-4oc likely to hit the western areas of Brazil. However,
precipitation models in Figure 2 suggest that there is uncertainty over precipitation changes
in 2100 as estimates range from -10 to 10% throughout the region. These maps from the
MET office were useful as they combined several models together in an attempt to get a
reliable estimate, the sizes of the squares in the key reflects the agreement on values
between the models studied.

3. Temperature variability
Figure 3 – Temperature projections for 2080-2100 (A2 business as usual scenario)
(Marengo, 2009)
Figure 4 – Precipitation projections for 2090-2100 (A2 business as usual scenario)
(Marengo, 2009)
Figure 3 demonstrates that predict that at a minimum, temperature changes are 2-3oC,
throughout most of Brazil, whereas increases of 3-4oC can be expected in the north and 4-6
oC in the North West, which would have detrimental impacts on crop yields.
Figure 4 is a major contrast from Figure 2 as it shows that precipitation changes by 2080 are
likely to be severe, with the North Western areas set to experience rainfall reductions at a
minimum of -20% and a maximum of -40%.

4. SeasonalChanges
Consequently, the above temperature changes imply that the frequency of frost free days
would rise (Marengo et al., 2010), which would present ideal conditions for crops as icy
conditions can be lethal for certain crops.
The periods of warm and dry days are also expected to increase during autumn and winter,
also ‘Veranicos’ (warm and dry days during autumn & winter) along with the occurrence of
dry spells lasting more than two weeks are likely to increase in the future (Marengo et al.,
2010). This could result in implications for crop yields as there would be an increased
demand for irrigation.
Extreme Weather Events
Table 1: Expectedextreme weather events by 2080 (Marengo etal., 2010)
Climatic change Impacts
Heatwaves The number of days above 32oc would
increase
Strong Winds Could make spraying of pesticides difficult
Drought Risk Severe for crop yields
Humidity As a result of rises in temperature and
water vapour, this could increase the
occurrence of diseases in Soybean crops

5. Agricultural Impacts
Brazil currently operates a No-tilling farming systemand multiple cropping where soybean
and maize are grown together (Brazil Ministry of Agriculture, 2015), which is very effective
as it reduces the influence from erosion and ensures that the soils are resilient and sustain
fertility. They also have a useful role in sequestering carbon (Ogle et al., 2012).
Table 2: Importance of crops by harvested area, Quantity and Value (FAO, 2008)
Table 2 shows an overview of that the most valuable crops produced in Brazil, where
soybeans are listed as one of the most valuable crops produced, with an estimated value of
$12.8 billion in 2008.
Table 3: Crop Yield Impacts Overview (Marengo et al., 2010)
Table 3 shows the predicted impacts on individual crops based on available potential area
under different A2 scenarios, and upon observation, soybean is shown as the most affected
crop in the future as it experiences the highest losses in areas from now to 2080 under a
business as usual scenario.

6. Figure 5: Key agricultural commodities in the Brazilian regions by planted area (Strohm et
al., 2012)
Figure 5 shows the importance of soybean across Brazil, where the focus will be on the
impacts on Western areas such as Mato Grosso, where soybean accounts for over 60% of
the total planted area.
Table 4: Estimate of soybean impacts in Mato Grosso (Zullo et al., 2008)
The main impacts of concern are an increased incidence of heat stress, where high
temperatures would be detrimental to soybean yields, where the optimal temperature for
soybeans is predicted to be approximately 23oC (Hatfield et al., 2011). Table 4 is alarming as
it shows the impacts of different temperature increases on soybean yield, and this can have
huge implications on farming in the Mato Grosso, where Figure 5 had highlighted soybean
as the main produce, as a temperature increase of 3oc was studied by Zullo et al. (2008) to
vastly reduce the suitable area available for soybean, along with huge economic implications
for the region, which illustrates the necessity for adopting adaptation strategies to
counteract these consequences.
In Western Amazonia, as well as parts of the Mato Grosso, the changing of land use from
forest to soybean is set to adversely affect the water balance, which would have an impact
on the local climate (Magrin et al., 2014). This would reduce the availability of water for
irrigation and could affect water resources in the area. This suggests the water needs of

7. soybean is set to rise significantly by 2080, coupled with the decrease in precipitation and
therefore measures to sustain water may be crucial for the Western regions of Brazil.
Soybean rusts are also predicted to become prevalent by 2080 (Magrin et al., 2014),
whereby the predicted rises in temperature and humidity are strongly linked to plant
disease as seen from climatic models (Alves et al., 2011).
It’s also important to note that soybean cultivation itself is contributing to climate change in
the western regions, since deforestation would result in a rise in temperature and a fall in
precipitation, especially in the dry seasons (Sampaio et al., 2007). It’s expected that this
clearing of land for cultivation will increase in future, therefore actions would need to be
taken to sustain soybean yields.
Adaptation Strategies
As the current population rate is set to vastly increase in the future to 2050, global soybean
yield would need to increase by 140% to accommodate the world population (Bruinsma,
2009). Therefore, this is quite crucial for Brazil due to its reputation as the second largest
soybean producing nation. In order to battle to sustain soybean yields in Western Brazil, a
variety of adaptation measures are needed.
WaterUse Efficiency
Improving water use efficiency would be necessary to implement pre-2080, in order to be
prepared for the predicted reduction in precipitation by a vast 20-40% in Western Brazil, as
shown in Figure 4. To achieve this, it’s necessary to promote techniques and cropping
systems of higher water use efficiency.
Firstly, it would be advisable to install sub surface drip irrigation on the soybean-Maize
cropped plots, as it is very water efficient in decreasing water demand and irrigation costs to
farmer (Levidow et al., 2014). These are drip lines which maintain irrigation for different
field lengths and helps leave space in the soil to store water from rainfall (Payero et al.,
2005). This technique works by ensuring water is irrigated through the crop, rather than on
the soil surface to reduce evaporation loss (Condon et al., 2004). This may be quite
expensive investment to install, though money would be saved in the long run, since in
order for Brazil to try and sustain their soybean yield nutrients, as shown in Table 4 where
there would be high financial constraints for a loss of yield.

8. Crop resistantcultivars
It would also be useful to invest in adapting new soybean crop varieties that are resistant to
future conditions such as heat stress, drought and diseases. Drought tolerant cultivators
adapted to future conditions is a useful option, as Sadok & Sinclair (2011) imply that taking
advantage of a genotype that helps reduce transpiration on the surface of the leaf and
would help conserve soil water.
Developing Soybean crop varieties adapted to higher temperature is necessary as soybean
optimal temperatures were studied to be around 23-24oC, where temperatures above this
range reduce yields with no yield at 39oC (Hatfield et al., 2011). Heat tolerance from new
crop variations should help farmers cope with future heatwaves that are predicted to
increase in duration (Table 1).
Pests and Diseaseprevention
Since climate change has a large influence on insect pest and pathogen outbreaks, this
would certainly be the case for Western Brazil (Sutherst et al., 2011), and would need to be
tackled in order to sustain soybean yields.
Integrated Pest Management (IPM) would be a good approach to follow, especially as Brazil
are ranked as one of the largest consumers of pesticides worldwide also since phytophagous
arthropods have been known reduce soybean productivity (Bueno et al.,2011). This focuses
on preventing pest influence through a range of methods such as through the use of
resistant cultivators, it also has the advantage of being economical and environmentally
friendly and is compatible with soil tillage, nutrient supply and water management (Juroszek
& Tiedemann, 2011).
Soybean could be at a higher risk of soil borne diseases (Vries et al., 2010), therefore
Cultivar breeding (Juroszek & Tiedemann, 2011) would be necessary to ensure that crops
are adapted to any disease since relative humidity and temperature is predicted to increase
in the future in Western Brazil.

9. Farm management practices
Crop rationing would be a useful practice to consider, to ensure that the water balance stays
stable by decreasing soybean’s water demand to aid in water conservation (Debaeke &
Aboudrare, 2004), this would especially be useful during veranico periods and to minimise
the destructive impacts of land clearance for soybean cultivation in areas such as Western
Amazonia.
Soil management practices such as conservation tillage would be useful to manage soil
fertility and reduce evaporation loss on the soil surface (Levidow et al., 2014). Conservation
tillage helps to maintain both soil fertility and the soil’s ability to hold water through
measures such as scheduling of irrigation at night to lower evaporation (Levidow et al.,
2014).
Making use of crop rotations would be helpful in decreasing the risk of disease in soybean,
the rotations would weaken pathogens that inflict soil borne diseases (Strand, 2000).
In addition, the planting dates of soybean would need to be modified to help sustain high
soybean yields, as Travasso et al. (2008) observed improved productivity in regions of
Uruguay and Argentina. Therefore, sowing soybean crops earlier the summer can prove
beneficial to sustaining yields in the future.

10. Conclusions
Climate change in Western Brazil is likely to result in temperature increases of
approximately 3-4oc and an annual precipitation decrease of up to 40% by 2080 under a
business as usual scenario. This would also result in extreme weather events such as
heatwaves, drought and an increase in humidity which would have drastic effects on
soybean yields. This is a huge concern for Brazil as soybean yield reductions would have a
heavy economic impact on Brazil’s agri-business sector and farmer’s income, especially in
regions such as Mato Grosso where soybean is the main crop. Adaptation strategies are
essential for Western Brazil, notably as land clearance for soybean would alter the local
climate further. Sustainable farm management practices, alongside strategies such as
improved water use efficiency, developing crop resistant cultivars and a controlled pest
management system would prove a worthwhile invest and can counteract the projected
yield declines predicted from a worst case climate scenario.

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