A guide to irrigation requirement of wheat crop in FAO-developed agro-climatic zones of Punjab, Pakistan

Water scarcity is a global concern exacerbated by human activities, including water mismanagement. The water shortage intensely impacts food production, as inadequate water is applied to the field for irrigation. Proper irrigation systems help to boost crop productivity and ensure food security. In arid and semi-arid regions, a limited amount of rainfall demands an understanding of crop water requirements (CWR). Climate change is the major suspect that further complicates irrigation management because as the temperature rises, evapotranspiration increases, leading to greater water demand by crops. Changes in rainfall patterns contribute to drought or floods that adversely affect crop production. To address these challenges, irrigation scheduling is essential to mitigate the effect of climate change on crop yield. This study determines the CWR and irrigation scheduling of Wheat in six districts of Punjab across the agro-climatic zones defined by the Food and Agricultural Organization (FAO), using CROPWAT software. Evapotranspiration was calculated using the Penman–Monteith method that utilize the climate data from 2013 to 2023. The selected station includes Mandibahauddin (MBD), Faisalabad (FSD), Toba Tek Singh (TTS), Bahawalpur (BWP), Bahawalnagar (BWN), and Khanpur (KNP). The results indicate that CWR varies in different stages of the crop; the lowest water requirement is in the initial stage, and the highest water requirement is in the mid-stage during crop development. During the dry season, the water requirement is high because rain can’t fulfill the crop’s water needs. Notably, southern Punjab BWP and KNP show maximum irrigation water requirements of 179, and 184.2 mm due to the dry climate compared to central region MBD, highlighting the influence of climatic variations. Unlike the previous studies focusing on specific districts, this research paper provides comprehensive irrigation scheduling across Punjab’s agro-climatic zones. Future studies should expand to include other crops to refine irrigation practices further.