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American Journal of  Agricultural Science, 
Engineering, and Technology (AJASET)

Prediction of  Wheat Storage Process Under Climate Change: A Case Study of  
Northwestern Regions of  Tunisia

Amal Barkouti1*, Mohamed Najib Melki1, Abdullah Beyaz2, Slaheddine Khlifi1

Volume 7 Issue 1, Year 2023
ISSN: 2158-8104 (Online), 2164-0920 (Print)

DOI: https://doi.org/10.54536/ajaset.v7i1.1056
https://journals.e-palli.com/home/index.php/ajaset

Article Information ABSTRACT

Received: December 06, 2022

Accepted: December 22, 2022

Published: January 01, 2023

In this work, a simulation of  the climate change impact on the wheat grain storage process 
in Northwestern regions of  Tunisia was investigated based on grain aeration systems. This 
simulation was conducted by implementing the software package called Zephyrus for a peri-
od from 2041 to 2070 during storage season from the 01st of  July to the 30th of  November. 
The model estimates grain moisture content, grain temperature, and dry matter loss. The re-
sults showed a significant potential of  the Zypherus strategy to maintain the grain moisture 
content around 12.2± 0.2% w.b. and to reduce grain temperatures from 35°C to 24 ± 1.5°C 
inside the silo. Consequently, under these values, the wheat storage process is considered 
safe and preserves wheat quality during the simulated storage period. Moreover, the wheat 
dry loss matter was about 0.8% during the whole storage period for each simulated year 
(approximately 0.15% per month).

Keywords
Climate Change, Dry Matter 
Loss, Moisture Content, Wheat 
Preserve Prediction, Zephyrus 
Strategy

1 Higher School of  Engineers of  Medjez El Bab, University of  Jendouba, Research Unit Renewable Energies In Agriculture and  
  Agro-Industry (ERAA), Route Du Kef, Km 5, 9070, Medjez El Bab, Tunisia.
2 Department of  Agricultural Machinery and Technologies Engineering, Faculty of  Agriculture, Ankara University, Dışkapı,  
  Ankara, Turkey.
* Corresponding author’s email: amalbarkouti@gmail.com

INTRODUCTION
Climate change predictions and their repercussions 
have become an increasing issue, that has interested 
considerably the scientific community. In the previous 
century, global mean temperatures have risen by more 
than 0.5 °C (IPOC, 2007), and the Intergovernmental 
Panel on Climate Change (IPCC) predicts that they will 
rise by 1.1 to 5.4 °C by 2100 (Bale et al., 2002). In the 
African continent, the average temperature will increase 
by more than 3°C by 2080 (Asafu-Adjaye, 2013). Of  its 
importance around the world and particularly in African 
countries, agriculture was the first sector to be affected 
by the climate-changing trends (Dinar et al., 2012; Adams 
et al. 1990) as like as world food production (Lobell et 
al., 2011). Climate change will have significant impacts on 
plant growth, agricultural productivity, and trends in the 
world’s food supply (Parry et al., 2005); as a result, it will 
all have a substantial impact on food security worldwide. 
To deal with the situation, numerous mitigating measures 
are being developed (Nayar, 2009). One of  these was 
safe food grain storage which is considered a way to 
achieve food security (Jayas, 2012) and adapt to the 
global changing climates (UNEP, 2010), particularly 
during times when agriculture is ineffective. Grain can be 
kept in silos, warehouses, bags, containers, conventional 
storage buildings, or other predetermined units (Moses 
et al., 2015). The farmer, the miller, the importer, and 
the government can store grain at various points along 
the food supply chain for different reasons. Their main 
objective is to satisfy customer demand for food grains. 
The stored grain is considered an artificial ecosystem that 
is constantly interacting with not only abiotic variables like 
temperature, relative humidity, intergranular CO2 levels, 
and moisture content but also with biotic ones like insect 

pests, fungi, mites, and rodents. With time, interactions 
continue, and unfavorable ones lead to grain degradation 
(Moses et al., 2015). Thus, Physical storage conditions, as 
well as different pests and illnesses that appear during the 
post-harvest phases of  agricultural commodities, have a 
significant impact on product quantity and quality (Rees, 
2004; Dowell & Dowell, 2017). To forecast mass and heat 
transfer in grain bins during the aeration process, some 
researchers have created and tested mathematical models. 
These models have been used to assess grain moisture 
content, temperature, and dry matter loss, making them 
useful tools for more advanced control strategies and for 
improving monitoring processes. (Frank & Howard,1995; 
Canchun et al., 2001; Devilla, 2002; Khatchatourian & 
Oliveira, 2006; Lopes et al., 2008).
Otherwise, the loss in quality and quantity of  grains during 
the storage process compels governments to import 
grains to satisfy citizen demand at a significantly higher 
cost. However, if  grains were protected and well stored, 
demand for imports could be decreased, saving significant 
foreign cash. Reducing losses for grain-exporting nations 
should increase income for the nation and its farmers, 
raising the standard of  life for its population. Therefore, a 
national strategy to provide a suitable infrastructure over 
several years and a suitable education plan via effective 
extension services for grain storage managers can greatly 
boost (Jayas, 2012).
In Tunisia, grain storage, in particular wheat storage, is 
an important process to ensure food security (Lakhoua, 
2019). The wheat sector has a significant gap between 
local demand and production (Chebil et al., 2015). 
Hence, nearly half  of  the wheat consumed during the 
past few decades was imported annually by the Tunisian 
government. Then, the cost of  importing wheat is rising 

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in tandem with its price on the global market, which 
raises the number of  government subsidies given to 
the industry, particularly during the global “food crisis” 
period (Laajimi et al., 2013). As a result, increasing wheat 
productivity and then managing the wheat storage process 
properly in Tunisia became essential for raising the wheat 
self-sufficiency ratio (Chebil et al., 2014; Lakhoua, 2019). 
In addition, Tunisia is one of  the north African countries 
which is affected by the climate-changing trends and many 
studies in the literature have dealt with the prediction 
of  Tunisian wheat production under climate change 
(Lhomme et al., 2009; Bahri et al., 2019) but there is a 
lack of  studies showing the impact of  climate change on 
wheat storage process. Hence, the objective of  this work 
is to study the future potential of  grain aeration during 
the storage process under climate change conditions in 
Tunisia. This study presents the impact of  temperature 
variability on the physical properties of  stored wheat 
using a process simulation and real data acquisition.

MATERIALS AND METHODS
Data and Climate Scenario
To describe the local effects of  anticipated ambient air 
temperature and relative humidity on the future of  the 
ambient aeration storage process, we used Regional 
Climate Models (RCMs). RCMs are frequently used to 
offer more specific information for a specific geographic 
area. RCMs integration is usually performed at a 
horizontal resolution of  10-50 km over a specific region 
of  interest. They can offer detailed temperature and 
moisture information for a particular region by combining 
explicit resolution techniques and parameterizations 
tailored to greater resolutions (IPCC, 2013). In this study, 
the regional climate models developed by the Swedish 
Meteorological and Hydrographic Institute (SMHI) were 
used to provide an hourly prediction of  temperature and 
relative humidity of  the ambient air of  the north-western 
regions of  Tunisia for 30 years period from 2041 to 
2070. The scenario RCP 4.5, often known as a moderate 
scenario, was used to assess the margin of  availability of  
favorable hours for grain aeration.

Storage Process Model
Simulations were conducted by software created based on 
the model presented by Thorpe (2001) and validated by 
Lopes et al. (2015). The program enables the simulation 
of  the aeration process in various air conditions. In this 
research, the aeration of  wheat grains during the storage 
process was controlled by the Zephyrus strategy described 
by Lopez & Steidle Neto (2019). This aeration controller 
is based on the forecasting of  air velocity and variations in 
temperature and moisture while air is circulated through a 
grain bulk. This work focused on wheat grain because it is 
the most grown cereal in Tunisia. It occupies more than 
50% of  the cereal area and contributes to more than 40% 
of  the cereal production (MA, 2012).  Additionally, the 
studied region (Northwestern region) is one of  the major 
producers and consumers of  this crop (Chebil et al., 

2015). The input data for the simulations were initial grain 
temperature (35 °C, the average ambient temperature in 
July when starts the storage process of  wheat grain in 
Tunisia), moisture content (13 % w.b.), grain bulk density 
(763 Kg m−3, durum wheat), geometric characteristics of  
the bin ( diameter 10 m, height 18 m), aeration airflow(6 
m3 h-1 t-1), the local atmospheric pressure and a file 
containing the hourly temperatures and relative humidity 
of  the ambient air for the storage period from July 01 
to November 30 for each year according to the SMHI 
models and according to the RCP 4.5 scenario for the 
period 2041-2070. Data of  ambient dry bulk temperature 
and relative humidity for the Northwestern regions of  
Tunisia were obtained from the website http://digilib.
icpac.net/

Figure 1: Schematic image of  the storage simulation 
process.

RESULTS AND DISCUSSION
Moisture content
Numerous factors, including soil temperature, solar 
radiation, ambient air temperature, and grain temperature, 
have an impact on the moisture content of  grains (Chang 
et al.,1994).
During storage, the grain must be shielded from climate 
variability, insects, and the development of  microbes to 
maintain its quality. The variations in air temperature 
and solar radiation from one season to another generate 
temperature gradients in the grain and thus move 
moisture from warmer to cooler grain areas. Then, the 
moisture buildup in a specific grain area encourages the 
growth and development of  fungi and insects (Hunt & 
Pixton, 1974; Chang et al., 1994).
The study conducted by Fan et al. (1961) on the water 
diffusion in different varieties of  wheat showed that 
the expression of  the diffusion coefficient of  moisture 
in wheat is a function of  the reciprocal of  absolute 
temperature. Jayas (2012) reported that storage at high 
moisture content and high temperature promotes quick 
spoilage of  the stored grain. Hence, to store safely wheat 
grains under tempered weather the moisture content 
should be around 12-13% w.b.
Figure 2 presents predicted wheat grain moisture contents 
for the studied years. For all of  the years under study, 

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Figure 2: Simulated wheat grain moisture content when using the Zephyrus strategy for three future decades years.

safe moisture contents were effectively maintained. All 
simulated moisture contents ranged from 13% to 12.2± 
0.2% w.b. for the whole study period, which corresponds 
to equilibrium relative humidities between 65.8% and 62 
± 0.2% when taking temperatures between 35 °C and 
24±1.5°C (Figure 3) into account. According to Weinberg 
et al. (2008) and Jayas (2012), under these circumstances, 
the growth of  microorganisms can be effectively stopped.
 
Grain Temperature
Figure 3 presents the evolution of  the average bulk grain 
temperatures throughout the whole simulated period. As 
shown, the Zephyrus system reduced grain temperatures 
from 35°C to around 24°C from July to November for 

each studied year.
For the first decade of  years (2041-2050), the grain 
temperatures decrease after almost 7 days from the 
beginning of  the storage process from 35°C to 24±1°C 
then this value was maintained until the end of  the 
month October. From this later the grain temperatures 
were slightly decreased (22°C) which can be explained by 
the decrease of  air ambient temperature in the Autumn 
season. For the two other decades of  years (2051-2060 
and 2061-2070), the same behavior was observed with a 
little bit of  difference in temperature values with 25±1°C 
for the maintained grain temperatures and then 20±1°C 
at the end of  October.

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Figure 3: Simulated wheat grain temperature when using the Zephyrus strategy for three future decades years.

production (Garcia-Cela et al., 2018; Meneghetti et al., 
2021). Figure 4 shows simulated dry matter loss of  stored 
wheat grain for each year of  the three decades years (2041 
- 2070). The behaviors of  the three decades years were 
similar. About 0.8% of  dry matter loss was observed for 

Dry matter loss
Wheat grain dry matter loss is influenced by moisture 
content, temperature, mechanical damage, type and 
severity of  microfloral infection, and insects. It is equally 
linked to the degree of  grain respiration and CO2 

Figure 4: Simulated dry matter losses when using the Zephyrus strategy for three future decades years.

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the whole storage period with about 0.15% per month in 
each year. This result is confirmed by the authors Polat 
(2013) and Kalsa et al. (2019) who reported in their works 
conducted on the wheat storage process in Turkey and 
Ethiopia respectively, a 0.11% dry matter loss per month.

CONCLUSION
The quality of  wheat grains during the storage 
process is mostly affected directly or indirectly by the 
temperature and moisture content. The prediction of  
these later for a period of  30 years from 2041 to 2070 
in Northwestern regions in Tunisia using the Zephyrus 
strategy was investigated. The results showed the safe 
storage of  wheat grains for the whole period. The two 
major factors grain temperature and moisture contents 
were maintained successfully around 24 ± 1.5°C and 
12.2± 0.2% w.b. respectively due to the aeration control 
strategy. This later also makes the dry matter loss amount 
not significant during the whole simulated period of  years 
with a percentage of  0.15% per month in each year.
Under the climate-changing conditions and the armed 
conflict between most cereals producers and exporters 
countries Russia and Ukraine, Tunisia has to enhance 
research and development in wheat grains storage 
techniques to ensure the wheat’s self-sufficiency ratio. 
This study is the first one conducted on the prediction 
of  wheat grains storage under climate change context in 
Tunisia in which results can be improved and completed 
by comparison with others models of  prediction and can 
be extended to study the potential of  the wheat grains 
storage process in other regions in Tunisia.

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