The Gambia is at the western end of West Africa, located at 13˚28.02' North 16˚34.02' West. The total territory area of the country is approximately 11,300 km², which is divided into landmass and water surface areas of approximately 1300 km² and 10,000 km², respectively, thus making the country one of the smallest in mainland Africa ( Ampomah et al., 2012 ; Belford et al., 2023 ). The country is situated in the tropical sub-humid ecoclimatic zone, with annual rainfall ranging from 800 to 1200 mm annually ( Kargbo et al., 2021 ). There are two seasons experienced in this climate zone: a rainy season (June to October) and a dry season (November to May) consisting of approximately six to seven months of dry period ( Josephine et al., 2020 ; Barrow et al., 2020 ). During the dry season, the climate is dominated by dry, and dusty winds, which originate from the Sahara Desert ( Kargbo et al., 2021 ).

The socio-cultural activities are associated with customs, lifestyles, and values, which characterize the demographics, religion, attitudes, economic status, class, and language ( Mutsikiwa & Basera, 2012 ). The 2013 Population and Housing Census revealed that The Gambia has a population of 1,882,450 with a density of 176 persons per km² ( Gambia Bureau of Statistics (GBoS), 2013 ; Josephine et al., 2020 ). The country has six Agricultural Administration Regions and an Urban Region, which comprises of Kanifing Municipal Council and Banjul. According to Jaiteh and Saho (2003) , the main ethnic groups were as follows: Mandingoes (36%), Fulani (22%), Wollofs (15%), Jolas (11%), Sarahuli (8%), Serer (2.5%)), Manjaku (1.7%) and others (4%) ( Badgie, 2018 ).

The Gambia is among those countries most vulnerable to climate change ( Camara, 2013 ). The Coastal wetlands, tidal flats, marshes, colluvial slopes, and uplands along the River Gambia characterize the topography of The Gambia. Rice and other crops are cultivated in all these highly variable environments, with land preparation and cropping techniques depending on the soil type, hydraulic conductivity, and tidal flows ( Engel-Di Mauro, 2012 ) ( Figure 1 ).

A cross-sectional study was conducted in the six Agricultural Regions of The Gambia from Number 2022 to March 2023. Primary data was used for the study. Primary data used was in the form of structured (quantitative research) questionnaires, Focus Group Discussions (FGDs), and Key Informant Interviews (KIIs) in 2023. The FGDs and KIIs used unstructured questionnaires (qualitative research). The structured questionnaires were administered to 432 crop farmers. Both the questionnaires (quantitative and qualitative) covered farmers’ knowledge and perceptions of the effects of climate variability and pollution on crop production and their varying adaptation strategies in The Gambia. The combination of both quantitative and qualitative approaches provides a more holistic understanding of the research question than either approach singly ( Creswell & Angeles, 2006 ).

Participants were carefully chosen using a random sampling approach. Adopting Al Mansour (2020) formula, where n is the sample size, z is the standard error associated with the chosen level of confidence (1.96), p is the estimated prevalence (0.50), q is 1 − p (0.50), and d is the acceptable error (0.05):

n = Z² × p (1 − p)/d²

From the above formula, a sample size of 384 was obtained, which was multiplied by 10% for sampling error to obtain 432 as the number of participants ( Al Mansour, 2020 ). Two districts from each of the five regions already described were randomly selected and within each selected district, two farming communities were purposively chosen for data collection. The purposive method of choosing the two communities for data collection stemmed from the fact that not all the communities were seriously engaged in crop farming but only the chosen communities were more involved in farming. In CRR-S, three districts such as Janjanbureh, Lower Fulladu, and Lower Fulladu West were chosen with one farming community in each of them except in Lower Fulladu West where two farming communities were chosen for data collection. The survey was conducted using 432 structured pre-tested questionnaires (228 males and 204 females) administered to crop farmers. The questionnaires were made up of both closed and open-ended questions, which were interpreted orally in the local languages (Mandinka, Fula, and Wolof) to the farmers and later translated back to the English Language consistently to enhance their applicability in various contexts.

Microsoft Excel spreadsheet program was used to manage the raw data. Epi info 7.2.5.0. Software statistical analysis tools were used to analyze and interpret the data. The obtained data was analyzed using descriptive statistics. The relationships between the predictor variable (gender, age, ethnic group, religion, marital status, and level of education) with knowledge and perceptions variables were examined using Pearson’s chi-square and Binomial Logistic Regression. P-value < 0.05 was considered statistically significant.

Out of the 432 crop farmers that participated in this study, 228 (52.78%) are males while 204 (47.22%) are females. About one-quarter of the participants 92 (21.30%) were between 40 - 49 years old, about half of the respondents 194 (44.91%) were between 50 and 59 years old, and about a quarter of the respondents 117 (27.08%) were 60 years and above. The findings showed that the main population engaged in crop farming is the aged population (50 years and above), which accounted for about 72%. This is attributed to the fact that most people believed that farming was meant for the illiterates, the less educated, and the poor. In contrast to the study conducted in Uganda by Ahaibwe et al. (2013) , which revealed that young farmers were concentrated more on agricultural production than adults despite the fact that the majority of them are less educated. The majority of the respondents 157 (36.34%) are Mandinkas by ethnicity followed by Fulas 107 (24.77%) and then Wolof 75 (17.36%) and others accounted for the rest of the respondents. On marital status, 354 (81.94%) of the respondents are married while 58 (13.43%) were single and the rest are either widowed or divorced. Regarding educational status, the highest number 171 (39.58%) of the respondents were illiterate followed by those who only attained primary education 82 (18.98%) ( Table 1 ).

Participants in this survey were asked about the main crop they grow, the type of farmland, whether they have changed crops in the past 20 years, and if they have changed crops, what the reason for the change of crops was. The results showed that 138 (31.94%) of the respondents grew rice, 212 (49.07%) grew groundnuts, 21 (4.86%) grew maize, 41 (9.49%) grew millet, 9 (2.08%) grew cassava and the rest grew one of the following crops; banana, lettuce, okra, and onion as shown in Table 2 . A similar study was conducted in the Central River Region of The Gambia, which indicated that 46.8% of the respondents grew rice, 45.2% grew groundnuts, while 1.4%, 5.3% and 2.08% grew maize, millet, and cassava respectively, and the rest grew other crops in the study area ( Badgie, 2018 ). About the type of farmland, 6 (1.39%) of the respondents cultivated their crops on state land, 81 (18.75%) cultivated their crops on communal land, 304 (70.37%) cultivated on individual land and 41 (9.49%) grown on rented land ( Table 2 ). In contrast, Badgie (2018) revealed that 18.75% of respondents cultivated their crops on communal land, 49.3% on individual land, and 9.49% on rented land. On the question of change of crops in the last 20 years, 421 (97.45%) of the respondents agreed that they have changed crops in the last 20 years and 11 (2.55%) said they have not changed crops in the last 20 years. The reasons for the change of crops were as follows; 135 (31.25% of the respondents argued that they changed crops due to short rainfall duration, 43 (9.95%) of them said because of drought, 175 (40.51%) attributed their change of crops to low soil fertility and 79 (18.29%) opined that incidence of pest and disease compelled them to change crops. Although these findings were supported by Seo and Mendelsohn, (2008) in South American farms, they pointed out that this may not be the case if the adjustment requires heavy investment. These findings are contrasted by the study conducted by Crane et al. (2011) , which reported that high climatic variability and unpredictable rain have led not only to changes in crops but almost every farmer now practices mixed agro-pastoralism and may also intermittently engage in fishing and hunting when possible. The diversification of crops and other sectors of the economy would minimize the total failure of the enterprises should the farmer encounter extreme climate events.

The perception of farmers on the effects of climate variability on crop production shows that, 426 (98.61%) respondents reported being aware of climate change. Almost all the respondents except for salt intrusion 241 (55.79%) reported that they have observed and experienced a change in temperature 422 (97.69%), rainfall pattern 430 (99.54%), erosion 427 (98.84%), windstorm 426 (98.61%, drought 418 (96.76%) and flood 432 (100.00%) over the past 20 years ( Table 3 ). According to meteorological evidence from Cham et al. (2018) , rainfall has decreased, the period of the rainy season has decreased, minimum temperatures have decreased, maximum temperatures have increased and the frequency of severe weather events such as drought and dust storms has increased in The Gambia over the past 60 years. This study revealed that crop farmers in The Gambia are very aware of the effects of climate variability on crop production. Except for salt intrusion, the overwhelming majority of more than 95% of the respondents are aware of climate change and perceived changes in temperature and rainfall patterns, a frequent occurrence in erosion, windstorms, drought, and flood as the main hazards caused by climate variability in the study area. A similar study was conducted in Ebonyi State, Nigeria, which demonstrated the majority of rice farmers perceived climate change events such as unpredictable rainfall patterns and distribution, prolonged dry season, frequent floods, increased temperature, and severe windstorms, which are in consonant with other scientific data resulting in poor yields and products ( Onyeneke et al., 2021 ). Another similar study in Uganda also revealed almost 99% of the respondents had perceived a change in the climate in the last decade ( Okonya et al., 2013 ). The farmers’ views on the causes of climate variability on crop production in The Gambia in the last 20 years are consistent with the study conducted in South Africa which shows that the risk of unprecedented high January-March (JFM) average temperatures is increasing, posing a growing threat to Agriculture ( Bradshaw et al., 2022 ). The majority (98.61%) of the respondents in The Gambia perceived the effects of climate variability on crop production. This is similar to the study conducted in Pakistan which reported that 91% of respondents in Pashawar perceived droughts as a major threat caused by weather and climate variability ( Khan et al., 2020 ). During the FGDs and KIIs with stakeholders, it was established that all the informants from the selected communities and institutions respectively were fully aware of climate variability and its effects on crop production.

Under the causes of climate variability, 71 (16.67%), 76 (17.59%), and 76 (17.59%) of respondents attributed climate change, temperature change, and change in rainfall to natural causes, whereas 100 (23.47%), 105 (24.31%) and 101 (23.38%) opined that it is due to human-induced activities. In contrast, the other respondents 245 (57.51%), 244 (56.48%), and 251 (58.10%) argued that both natural and human-induced activities are the causes of change in climate, change in temperature and change in rainfall respectively while 10 (2.34%), 7 (1.62%) and 4 (0.93%) said that they do not know the cause of climate change, change in temperature and change in rainfall respectively ( Table 4 ).

The findings as shown in Table 4 , revealed that more than 50% of the farmers attributed the causes of climate variability such as temperature and rainfall to the interplay of both natural and human-induced activities. A similar study was conducted in Nigeria, which opined that changes in climate and environmental conditions occur as a result of both natural and human factors ( Nwankwoala, 2015 ). This is in consonant with the study conducted by Hartter et al. (2018) in eastern Oregon (USA), where most of the respondents did not accept human causation as the only agent of climate change. However, a large majority (85% - 86%) of them agree that the climate is changing, either by natural or human-induced causes ( Hartter et al., 2018 ). In contrast with the study conducted by Perkins-Kirkpatrick et al. (2022) which opined that extreme events that influence climate change are attributed to anthropogenic activities.

The perception of crop farmers towards the effects of elevated temperature on crop production shows that 400 respondents (92.59%) reported a decrease in crop production, 20 (4.63%) stated an increase, 8 (1.85%) believed that the elevated temperature has no effect, and 4 (0.93%) were unsure of any effects ( Figure 2 ). This is in consonant with the research conducted in Slovakia by Varga (2021) , which argued that the impacts of climate change would be felt in agriculture leading to reduced production in warmer areas due to temperature stress, risk of erosion as a result of more extreme weather conditions, the occurrence of new pests, etc.

The crop farmers were asked about the effects of changes in rainfall patterns on crop growth, development, and production. The results show that 403 (93.29%) reported that they observed reduced crop growth, development, and production, 22 (5.09%) stated that there was an increase in crop growth, development, and production, 3 (0.69%) said that it does not affect crop growth, development, and production while 4 (0.93%) reported that they had no idea about the resultant effects of changes in rainfall pattern on crop growth, development, and production ( Figure 3 ).

Figure 4 shows the various effects of climate variability and pollution on the environment such as high temperatures 198 (45.83%), less or erratic rainfall 48 (11.11%), floods increase on farms 28 (6.48%), late onset of rains 34 (7.87%), less crop yield 79 (18.29%), increased winds before rains 17 (3.94%) and land degradation 28 (6.48%). A similar study in Nigeria pointed out that the majority (more than 70%) of farmers perceived an increase in temperature and a decrease in precipitation patterns ( Sofoluwe et al., 2011 ).

A study conducted by Agwu et al. (2018) showed that farmers in Nigeria are well aware of climate change, and its impact on crop productivity stressing that the variability of the Harmattan season influences fruit production of the Garcinia kola. Mertz et al. (2009) , which analyzed the perceptions of climate change and the strategies for coping and adaptation in the savannah zone of central Senegal agreed that households are aware of climate variability and identified wind and occasional excess rainfall as the most destructive climate events. The findings of Odewumi et al. (2013) in Ibadan, South-western Nigeria, on farmers’ perception of the effect of climate change and variations on urban agriculture indicated that 89.6% of the respondents had agreed that climate is changing. Similarly, research has revealed that about 89% of the farmers perceived a significant increase in temperature, 72% perceived high evapotranspiration rates, 68% showed that there had been violent rain and hailstorms, and 65% experienced delayed rainfall and early cessation ( Chalchisa & Sani, 2016 ).

Table 5 shows Pearson chi-square results on farmers’ perception of the effects of climate variability on crop production in The Gambia. The analysis indicates that marital status is the only demographic variable that showed a significant association with all questions about climate variability effects on crop husbandry in The Gambia. Furthermore, the chi-square analysis test showed that the highest level of education is significantly associated with farmers’ perception of the effects of erosion, windstorms, and salt intrusion on crop production in their communities. These findings suggest that crop farmers in The Gambia know the adverse effects of climate variability on food security. Furthermore, the chi-square analysis tests also showed that age and ethnic group were also significant in determining crop farmers’ perception of the effects of salt intrusion on crop production in their communities. In contrast, a study conducted in the Nile Basin of Ethiopia by Deressa et al. (2011) , showed only age as being significantly related to farmers’ perception of climate change.

*= significant difference at P < 0.05; ^ns = not significant.

Table 6 shows the binomial logistic regression result of how crop farmers perceived the contamination of agricultural land in The Gambia. This result shows that farmers’ ages (CL −0.135 to −0.020 and P = 0.008) and ethnic groups (CL 0.068 to 0.188 and P ≤ 0.001) were the main factors significantly influencing their perception of the awareness of HM pollution on land. Farmers’ ages (CL −0.167 to −0.054 and P ≤ 0.001) and ethnic groups (CL 0.053 to 0.171 and P ≤ 0.001) were also highly significantly associated with their awareness of threats posed by HM contamination in soil and water.

The age of the respondents represents experience in farming and research has shown that experienced farmers are more likely to perceive climate change ( Ishaya & Abaje, 2008 ; Deressa et al., 2011 ).

Table 7 shows the responses of crop farmers about their perceptions of the contamination of agricultural land. The majority of 358 (82.87%) of the informants had experienced soil and water pollution on their farms. These findings revealed that although the farmers in The Gambia had never experienced HM pollution on their farms, 109 (25.23%) of them are aware of the threats posed by these recalcitrant substances to the environment ( Table 7 ). This may be because there is little or no analysis of the content of heavy metals in the fertilizers, chemicals, and pesticides used on the arable soil. With this little knowledge of HM contamination in The Gambia, bioremediation technology, which is not only meant for HM removal but also those contaminants with organic substances origin, is an exotic phenomenon. In contrast with the study conducted in Lankao County, China by Ren et al. (2018) , which showed from the questionnaire that the content of heavy metal in various arable soils is closely related to the input of fertilizer, pesticide, farmyard manure, etc. In addition, another study conducted by Lu (2019) , opined that farmers in China believe that their cultivated land is moderately polluted by heavy metals and they have a strong awareness of HM pollution in locally cultivated land. Research conducted by Ren et al. (2018) revealed that HM contamination remediation of arable soil indicates that the adoption of appropriate treatment measures can reduce the HM content of arable soil to some extent, such as the adjustment of planting patterns, deep ploughing for soil amelioration, formula fertilization, and adoption of phytoremediation (an aspect of bioremediation), etc.

Figure 5 shows the main soil and water pollution in The Gambia. The findings revealed that the main soil and water pollution emanates from both organic and inorganic contaminants, 163 (45.53%) attributed the pollution to chemical fertilizers, 39 (10.89%) said that pesticides cause the pollution, 81 (22.63%) argued that industrial and agricultural wastes cause the pollution, 74 (20.67%) of them opined that their farmlands are polluted by sewage and 1 (0.28%) of the farmers said that other agents cause the pollution ( Figure 5 ). Similarly, the research of Srivastav (2020) , showed that several researchers have reported the risks to environmental systems due to overuse and prolonged application of chemical fertilizers and pesticides, which would invariably promote soil health deterioration along with environmental pollution.

It was also revealed in the FGD sessions that, most of the upstream farmers were less affected by pollution than those farmers in the coastal and riverine agricultural areas. Contrastingly, the research conducted in the United States by Chakraborti (2021) concluded that point sources have a significant negative impact on ambient water quality net of non-point sources of contamination at upstream locations. However, during the FDG sessions, the coastal and riverine farmers complained of pollution emanating from indiscriminate disposal of plastic bags, agrochemicals, pesticides, salt intrusion, oil spillage, and runoff from dump sites, to name a few. HM pollution was not mentioned which could be attributed to the fact that there is little or no evidence of any study on HM pollution in The Gambia.

The field surveys showed ( Table 8 ) the challenges faced in responding to climate variability in the study area. Inadequate access to credit facilities and efficient inputs was ranked first with a high number of respondents 288 (66.67%) each in militating against farmers in their response to climate change. This was followed by labour constraints, inadequate access to the market, inadequate access to water and irrigation facilities, inadequate access to information, and use of poor skills, salt intrusion, and inadequate access to ideal land as they ranked third 240 (55.56%), fourth 239 (55.32%), fifth 222 (51.39%), sixth 165 (38.19%), seventh 134 (31.02%) and eighth 101 (23.38%) respectively. These findings are in consonant with that of Idrisa et al. (2012) who reported that inadequate financial resources (credit), inadequate access to extension services, poor access to technologies required for adaptation and inadequate weather information were the challenges confronting farmers’ adaptation to climate change in Borno State, Nigeria. However, research conducted in India by Satishkumar et al. (2013) had a divergent perspective which revealed that personal constraints like the small size and fragmented landholdings, low literacy level, and inadequate knowledge of how to cope or build resilience are the main hurdles confronting agrarian industry. The same research also pointed out that the farmers faced poor extension service on climate risk management, non-availability of drought-tolerant varieties, lack of access to weather forecasting technology, poor reliability, and dependence on monsoon were the major institutional and technological constraints.

The agrarian industry has over the years proven to have the capability of responding to changing climate events by adopting various strategies and innovations as the circumstances may deem fit. The survey shows the most common adaptation strategies employed by farmers to cope with the changing climate ( Table 9 ).

The possible adaptation strategies employed by farmers in The Gambia towards climate change indicated that about 141 (32.79%) of the farmers specified that planting drought-resistant crop varieties would help solve challenges and increase their crop yields. This is in agreement with research conducted in Nigeria, Senegal, Burkina Faso, and Ghana, which pointed out that smallholder farmers have used, drought-resistant crop varieties as an adaptation method to climate change ( Akinnagbe & Irohibe, 2015 ). Again, 187 (43.29%) of the informants opined that the adoption of crop diversification has helped a great deal to reduce the loss they normally encountered on their farms. According to them, if the government can supply them with various crop varieties to grow, some may fail because of the harsh climatic conditions but others will thrive. Similar research conducted in Tanzania revealed that farmers diversified crop varieties as a way of spreading risks on the farm ( Orindi & Eriksen, 2005 ; Adger et al., 2003 ). Crop diversification can serve as insurance against rainfall variability ( Akinnagbe & Irohibe, 2015 ).

Other respondents representing 60 (13.89%) indicated that improved irrigation efficiency would enable them to grow their crops all year round. This would ensure the availability of food security at all times instead of seasonality. A study conducted by Akinnagbe and Irohibe (2015) stressed that the impacts of climate change have resulted in elevated crop water demand due to high evapotranspiration ( FAO, 2006 ). In addition, 61 (14.12%) of the respondents argued that afforestation and agroforestry would help prevent erosion and maintain soil fertility, eventually boosting their crop yields. Research has revealed that a practice similar to this has been described in the southwestern part of Nigeria to raise shade-tolerant crops, such as Dioscorea spp., and cocoyam in essentially permanent forest settings. In the drier parts of the Sahel, African baobab (Adansonia digitata) and acacia (Acacia spp.) trees are usually planted by local farmers since they are also economically valuable trees, especially during the hot and dry parts of the year ( Akinnagbe & Irohibe, 2015 ). Another 118 (27.31%) of the respondents opined that the practice of a crop rotation system would help replenish the depleted soil nutrients thereby improving crop yield. Further, 101 (23.38%) of the respondents pointed out that the use of chemical fertilizers could also help enhance their adaptation to climate change and reduce the losses incurred on farms. They cried out that the price of fertilizers set by the government was too high for average farmers hence most of them could not afford them. Almost half 215 (49.77%) of the respondents settled for the use of organic manure as a means of adaptation strategy to mitigate the effect of climate change. Although zero tillage is not a familiar method used by farmers in The Gambia to reduce the adverse effects of climate change on their crop production, few 27 (6.25%) of them embraced the strategy to improve crop yields. The majority 254 (58.80%) and 252 (58.33%) of the respondents employed early maturing varieties and migration to different locations respectively as crop adaptation strategies towards climate change. These findings are in line with a survey conducted in the Zou Department of South Benin, which revealed that farmers adopted many strategies such as mulching, organic fertilizer, the use of improved varieties, chemical fertilizers, and pesticides in response to climate change: agroforestry and perennial plantation diversification of income-generating activities ( Fadina & Barjolle, 2018 ). Although the findings of this research show some similarities with research conducted by Akinnagbe and Irohibe (2015) , the common agricultural adaptation strategies adopted by farmers in Nigeria were the use of drought-resistant varieties of crops, crop diversification, changes in cropping patterns and calendar of planting, conserving soil moisture through appropriate tillage methods, improving irrigation efficiency, and afforestation and agro-forestry. In the West African Sahel, recent studies have shown that the region has suffered a prolonged drought for much of the past three decades and one way that farmers have adapted is by sending young men and women in search of wage labour after each harvest. However, how far they travel depends, in part, on the success of the harvest ( Akinnagbe & Irohibe, 2015 ). More generally, environmental migrants are, most of the time, people affected by long-term and permanent climate variations in temperature and precipitations; hence, they consider the migration process as a long-run adaptation strategy ( Falco et al., 2018 ). This study showed that adaptation strategies such as improved irrigation efficiency, afforestation and agroforestry, and zero tillage were not always used ( Table 9 ).

However, participants in the KIIs stressed that activities such as the use of clean energy (solar, windmills, hydrogen-powered vehicles), afforestation, selective exploitation, avoidance of excessive use of fertilizers, the use of anti-littering policy, crop rotation, bush fallowing, adoption of climate-smart agricultural practices (minimum tillage, improved crop varieties, farmyard manure, water-saving technology, biopesticides, etc.), raise awareness through campaigns would help attitudinal change towards the environment and environmental policy formulation and implementation can help mitigate the effects of climate change.