CLIMATE CHANGE EFFECTS AND ADAPTATION MEASURES FOR CROP PRODUCTION IN SOUTH WEST COAST OF BANGLADESH

Adaptive measure, Climate change, Water scarcity, Salinity A survey was conducted to determine the effect of climate change on crop production and water quality in 12 villages of Deluty and Garaikhali unions under Paikgacha upazila of Khulna district, Bangladesh. Total of 100 farmers were interviewed using a pre-tested questionnaire. The climatic hazards as reported on the study area are salinity, cyclone, drought, hailstorm, river erosion and waterlogging, of them salinity is the most dominant hazard. Due to salinity the cropping system has undergone changes. Many crops and varieties have been either extinct or their cultivation has come down. Both soil and water are severely affected by salinity. Most of the farmers (90%) use pond water for irrigation and the majority farmers use pond and rain waters for drinking purpose. Results of the present study serves as a good basis for in-depth study to achieve successful crop production in the south west coastal area of Bangladesh.


INTRODUCTION
Bangladesh is often cited as one of the most vulnerable countries to climate change in the world (MoA and FAO, 2013).The vulnerability to climate change is high due to a number of hydro-geological and socio-economic factors (Ahmed, 2004(Ahmed, , 2006)).The country often experiences natural disasters as an effect of climate change, particularly in coastal areas.Crop agriculture is often constrained by different hazards and disasters such as floods, droughts, soil and water salinity, cyclones and storm surges (MoEF, 2009).Salinity is a great constraint to growing crops, especially in rabi season (dry months) when water and soil salinity arises and reaches to the peak in March-April before monsoon starts (Haque et al., 2008(Haque et al., , 2014)).
The main crop grown in the saline areas is local transplanted aman rice which has low yield potential.Haque (2006) reported that most of the coastal areas are located over medium highlands, where flooding depth ranges from 0.3-0.9meter.This category of land is suitable for the minimum two crops and three crops could be possible if some suitable interventions are done.Kim et al., (2016) described that the decrease in crop yields with the increase in the salinity of irrigation water was caused by disturbances in physiological and biochemical activities under saline conditions.
Salinity causes unfavorable environment and hydrological situation that restrict the normal crop growth.The factors which contribute significantly to the development of saline soil are tidal flooding during wet season (June-October), direct inundation by saline water, and upward or lateral movement of saline ground water during dry season (November-May) (Karim et al.,1990).The prevailing salinity intrusion due to climate change has severely affecting the crop productivity in the saline regions of Bangladesh (Haque, et al., 2015).Although people of the south-west region of the country are mostly dependent on crop farming, most of the farmers do not know how to address soil salinity by modern techniques for better crop production.The present study was done to find out the effects of climate change with special focus in salinity on crop production and to identify the adaptation measures used by the farmers to cope with salinity.

Selection of the study area
Recent rapid industrialization in the developed countries and deforestation increased global warming.Due to global warming sea level is raised and ultimately low laying area of the world is inundated by saline sea water.Due to deltaic geography of Bangladesh, the country is most vulnerable to climate change.Among the thirteen coastal districts, Khulna is most affected by climate change.Under this district Paikgacha upazila is one of the worst affected upazilas by natural disasters such as salinization, cyclone, drought, hailstorm, river erosion and waterlogging.This situation is a big threat to successful crop production.To achieve the objectives a survey work was done at 12 villages of Paikgacha upazila under Khulna district.The villages were Fulbari, Bigordana, Gobipagla, Horinkhola, Hatbari, Senerber, Kalinagar, Telikhali, Noldanga, Darunmallik, Kumkhali and Bainbariya covering two unions -Deluty and Garaikhali.

Population and sampling
Total 100 farmers across the villages were randomly selected.In order to estimate the existing hazards with their severity and adverse effects on crop production, the respondents were asked some common questions.

Data collection and analysis
Before data collection, an interview schedule was prepared keeping in view the objectives of the study.Then it was pre-tested among the population who were not included in the sample.After necessary corrections and modifications, a final questionnaire was prepared and multiplied.Data were collected through face to face interview with the respondents.The data generated from this experiment were entered in Microsoft Excel Worksheet, checked, organized and processed for further analysis.Frequency and percentage for different variables were estimated with help of SPSS 17 computer software.

Socio-economic status of the farmers
The socio-economic status in the present study includes age, education and land ownership of the farmers.It is summarized and presented in Table1.It was found that 14% of the respondents belonged to young aged group (15-30 years), followed by 33% middle aged group (31-45 years), 36% 46-60 years aged group,15% 61-75 years aged group and only 2% old aged group (76-90 Year).About 47% of the farmers received secondary education followed by 30% primary education, 8% higher secondary education, 6% illiterate, 4% can sign only, 3% above higher secondary education and 2% can read and sign only.In case of household size,46% households were small (1-4), 49% medium (5)(6)(7)(8), 5% large and 1% was very large.

Temporal variability of crop cultivation
Cultivation of crops markedly varied with advancement of years.Variation was recorded from past 15 years to the present year (Table 2).The most common crop in the area is T. aman rice followed by bitter gourd.Ausrice cultivation ceases and Boro cultivation is minimum.In case of Aus rice, watermelon, sweet potato, jute, dhaincha, melon and cucumber cultivation, a decreasing trend was found.Ten percent of the farmers were engaged in Aus rice cultivation in 10-15 years ago but now Aus rice is no more cultivated.In this salt affected area transplanted Aman rice (July-November) is the dominant crop and farmers mainly cultivate it.But a decreasing trend also found in case of Aman rice due to salinity.Rahman et al.(2015) reported that risk of cyclone occurrence is high in April -May (pre-monsoon) and October -November (post-monsoon).Local farmers cultivate pulse, T-aus, T-aman and some minor vegetables during pre and post monsoon and these crops are highly vulnerable to cyclone and storm surges.
Presently the farmers have started to use drought and salinity tolerant crops and varieties as adaptive measures.These crops include bitter gourd, sweat gourd, okra, sesame, ridge gourd and bottle gourd.Cultivation of bitter gourd has remarkably increased.

Major climatic hazards
While investigating farmer's perception, different farmer emphasize on different problems that constrain crop production, it is shown in Table 4.It is clear that salinity, cyclone and monsoon storm is the most impacted hazards in crop agriculture.Next to them, drought, continuous rain,hailstorm, river erosion and waterlogging are the common limitations for crop production in the area.As per World Bank report (2001), 14, 32, and 88 cm sea level rise will occur in 2030, 2050 and 2100, respectively which may inundate about 8, 10 and 16% of total land of Bangladesh.Sea level is rising by about 3 mm/year.Cyclone, floods and tidal surges are common disasters in the coastal regions.Table 4 also indicates that the frequency of salinity, drought and continuous rain are increasing with time.About 95% respondents opine that in the previous year their crops were heavily affected by salinity.

Names of major hazards
Year-1 1- Adaptation measures to cope with the salinity Table 5 demonstrates the existing adaptation options against the climate stress in the study area.It appears that salinity, cyclone, monsoon storm, excessive rain, waterlog, river erosion, droughts and hailstorms are the major climate stresses across the regions.Different types of adaption options are found from the study areas against the climate stresses to minimize the loss and damage.Adaptation practices varied depending on the technical and financial capacity of the farmers.Most of the farmers (65%) prefer homestead cultivation, appropriate fertilization (56%) and mulching (28%) as adaptive measures to suppress salinity.

Causes of salinity
There are two main causes of salinity, one is natural causes and another is human induced causes.In case of natural causes, the majority farmers (70%) emphasized on tidal flooding.They also mentioned sea level rise (37%), increasing temperature (23%), increase of saline intrusion (32%), reduced dry season flow in the Shoilmari River (3%) and cyclone (11%) as a natural causes of increasing salinity in their locality.On the other hand, according to farmer's perception extensive shrimp cultivation, construction of Farakka barrage, faulty management of coastal polders and faulty management of sluice gate are human induced causes of increasing salinity (Table 6).

Salinity effects on farming enterprises
Crop agriculture is highly affected by salinity and farmers are the direct victims.Farming enterprises affected by salinity is summarized and presented in Figure 1.It was found that 95% of the farmer thought that their crops are affected by salinity followed by homestead by 32%, fisheries by 18% and livestock by 3%.

Sources of sweet water for irrigation
Data analysis shows that in the current study area there are very limited sources of sweet water for irrigation.About 70% farmers view that there is unavailability of sweet water for irrigation, they have accessibility to use only four types of sweet water sources for irrigation namely pond water, tube well, rain water and canal water.
Farmers widely use pond water as irrigation water and the rest of the sources have very limited use.About 90% of the farmers use pond water while tube well by 1%, rain water by 1% and canal water by 2%.

Adaptation measures in collecting drinking water
Table 7 is designed to identify the adaptation measures followed in collecting drinking water to cope with salinity both at individual and community levels.Different farmers follow different methods but in few cases they have high They collect water from far distance, harvest rainwater, dug well, conserve pond water, install tube-well and purchase water as methods of individual effort.Among these methods most of the farmers follow collecting water from far distance and harvesting rainwater.On the other hand in case of community basis effort farmers emphasize on use of pond and filter water (34%) followed by conservation of pond water (29%), digging of pond (11%) and installation of deep tube-well (4%).

Organizations involved in salinity mitigation
Figure 3 shows that government, some international and some local organizations have programmes to mitigate salinity in their locality, and however they did not mention any private sector or any other organizations.About 37% of the farmers tell that government organization do this job where 13% by international organization and 16% by local organization.

Figure 3. Organizations involved in mitigation of salinity
In study there were seven indicators of adaptive measure to assess the degree of measures that taken by different organization (Table 8) through asking the farmers.It revealed that almost all of the adaptive measures were taken by different organizations.In case of government organization farmers emphasized on Department of Agricultural Extension (DAE), Water Development Board (WDB), Local Government Engineering Department (LGED) and Soil Resource Development Institute (SRDI).In case of international organization they emphasized on Blue Gold and in case of local non-government organization they suggest two organizations-Sofol and Soliderist.

Table 1 .
Socio-economic status of the farmers

Table 3 .
Temporal variability in cropping patterns in the study area

Table 5 .
Adaptive measures used by the farmers to cope with salinity

Table 6 .
Percent respondent perception about causes of increasing salinity in the study area

Table 7 .
Adaptation measures followed by farmers to cope with salinity