The global climate is changing, and projections have been made that the rate will be extreme by this century (Zhang et al., 2024; Zhang et al., 2023). The global temperature is expected to be higher, which may lead to drought and water scarcity (Shariot-Ullah, 2024; Boehm & Bischel, 2019; UNICEF, 2021). Moreover, extensive utilization of irrigation water for agriculture (approximately 69% of world’s freshwater) is pressurizing the limited fresh water resources (Manocha et al., 2024; Sepaskhah & Ahmadi, 2010). Specifically, in arid and semiarid regions, water scarcity threatens socioeconomic and environmental progress, as water plays an important role in the production process of food (Sentlinger & Writer, 2015; Slama et al., 2019). Agriculture is taking the major share (approximately 70%) of freshwater and climate change-induced water scarcity affecting food security and has received global attention in the last few decades. This challenge to food security is a great threat to achieving sustainable development goals (Nouri et al., 2019; UNDESA, 2014; Wu et al., 2021a). Therefore, understanding the changes in irrigation requirements of major crops is important to ensure water and food security under climate change.
The limited land is reducing, and the population is increasing in Bangladesh. Therefore, Bangladesh needs to produce more food in less land to satisfy the food security goal (Jahan et al., 2016). Potato is one of the major crops that requires a short time to grow. It can be one of the substitutes for rice both in terms of nutrition and high carbohydrate contents and can reduce the pressure on rice and wheat as rice production is projected to be reduced (approximately 12.44% yield loss for the 1.5°C scenario) in Bangladesh in the future due to climate change. People of all classes in Bangladesh consume potato as vegetables. Fortunately, potato production has increased significantly over the years. The production of potato increased from 3.281 Metric ton in 1970-71 to 19.647 Metric ton in 2014–2015 (BBS, 2018; Hoque, 2001; Wu et al., 2021b). However, water management in potato cultivation is critical as this plant is one of the most water stress-sensitive plants due to its shallow rooting system.
Tang et al. (2021) simulated the optimization of the water requirement using the combination of irrigation (irrigation requirement 10–100 mm) and nitrogen fertilizer (0-210 kg h−1 on potato yield in North China from 1981 to 2010 by using the APSIM-potato model and reported an increase in yield (35.2 t ha− 1) for the irrigation requirement of 10 mm, which was obtained under middle APE (agro-pastoral ecotone). Waqas et al. (2021) supplied delayed irrigation to observe the effects on the yield parameters and water productivity of potato under furrow and drip irrigation and observed that 35% of the depleted available plant water gave the highest water productivity, although the control treatment gave the highest yield. Thirty-five percent of plant water depletion increased water productivity by 13.31 kg m− 3, saving 40.44% of water compared to the control. As production is increasing, more irrigation and optimization are needed to produce more potato now and in the future. Salam & Al-Mazrooei (2007) carried out an experiment in Kuwait on potatoes in loamy sandy soil by using the CropWat model by using 43 years of meteorological data and found that the annual average reference crop evapotranspiration over the past 43 years was 2882.5 mm and varied from 2.75 mmd-1 to 14.0 mmd-1 in January and June, respectively. They also observed the varied irrigation water requirement and other crop water requirement indexes with the date of planting. Vishnoi et al. (2012) also reported the same finding that water requirements vary with planting date. They estimated the crop water requirement of potato by CropWat at Uttarakhand and Pantnagar and reported the total water requirement at late date (226.7 mm was higher than the earlier date (212.5 mm)). Mojid et al. (2020) estimated crop evapotranspiration and irrigation requirements along with the trend by using CropWat and MAKESENS for the major crops in the northwestern part of Bangladesh (Bogura and Rajshahi districts) from 1985 to 2013 and reported a decreased irrigation requirement for potato cultivation in Bogura, although the scenario started to change after 2000. An increase in total crop evapotranspiration (ETc) was observed for potato, which gives a sign of a shift from wheat to potato.
The yield and quality of potatoes depend on the water availability and shortage and vary with the texture of the soil. For commercialized potato cultivation, maintaining optimum irrigation is essential, as it is water sensitive, and this practice is practiced globally. The yield may start to decrease if the water deviates even from the optimum. Therefore, to maximize the yield of potato, it is a prerequisite to quantitatively manage irrigation (King et al., 2020).
Future projection depicting that agriculture will have to face the severe adversity of climate change in upcoming years and will impact significantly on agricultural water management, especially in the climate change hotspot in southern Europe and semiarid regions since the water for irrigation is approximately 80% and 25% in Europe and in some of the Mediterranean countries, respectively, which is a great threat to food security (Masia et al., 2021). The excessive use of water threatens this essential resource and becomes crucial to address the pathways for the proper planning and management of irrigation. To support optimized planning for proper irrigation water management, a crop-growth model is a powerful tool and is being used worldwide (Kelly & Foster, 2021). One of the major ways to estimate and optimize irrigation water management is crop water modelling in the future to provide guidelines for policymakers and farmers to adopt necessary strategies to cope with future climate-induced challenges in water sectors (Vishnoi et al., 2012).
Although this is important to address the scenario for the future, research in this field is scarce in the water-scarce northwestern part of Bangladesh. Thus, this study aimed to understand the changes in irrigation requirements for sustainable potato production under climate change to ensure water and food security goals.