Mitigation of agricultural drought using deficit but supplemental irrigation methods and practices

This paper presents the hydro-meteorological analysis of the Indus Basin of Pakistan, and compares it with the crop water demands and canal water supplies to identify agricultural drought prone canal command areas. Monthly rainfall data for 35 years (1960-95), from twenty-six weather stations spread across the Indus Basin, was used for the meteorological analysis. Crop water demands at various stages of crop growth was calculated using reference evapotranspiration (ET0) value obtained from CROPWAT, and canal water supplies were calculated from daily gauge readings recorded at head of the canal. Participatory Rural Appraisal (PRA) was made in these drought prone canal command areas to comprehend the experiences of different farmers in addressing dry spells and water stress conditions. PRA results revealed that farmers rely more in using groundwater to meet the irrigation water demands, and farmers had tendency to over irrigate their cropped lands using canal water conjunctively with groundwater 'an approach that runs counter to the conservation of scarce resources. SWAP was used to evaluate these current practices on long-term basis, and concluded that these had tendency to create problems of land degradation and consequent crop yield reductions. Therefore, to address these anticipating problems, the idea of deficit but supplemental irrigation methods and practices was evaluated using SWAP, and the developed guidelines were tested under farmers' management with a purpose of promoting sustainable use of available water resources (quantity and quality) to address dry spells and water stress conditions. Due to socio-economical implications associated with the proposed interventions used for implementing the developed guidelines, both private and public sectors should play their respective roles more actively in educating farmers by introducing the research results to the farming communities.