An analysis on evaluation of virtual water index of horticultural and field crops grown in Iran

Understanding the virtual water content of agricultural products is a key step toward improving water-use efficiency in water-scarce regions. Iran, characterized by its predominantly arid and semi-arid climate, faces severe water limitations that challenge the sustainability of its cropping systems. This study quantified the virtual water content of major horticultural and field crops in Iran using ten-year data (2013–2023) to evaluate agricultural water-use efficiency under arid and semi-arid conditions. Based on the crop water consumption index (L kg⁻¹), crops were categorized as high- or low-water-demand using a 400 L kg⁻¹ benchmark. Results showed a wide variation in virtual water content, ranging from 26.5 to 6,327.7 L kg⁻¹. Among horticultural crops, pistachio (6,327.7 L kg⁻¹) and nectarine (405.7 L kg⁻¹) represented the highest and lowest values, while sesame (4,157.4 L kg⁻¹) and clover (696.5 L kg⁻¹) were the extremes among field crops. High-water-demand crops accounted for 92.5% of total virtual water use, indicating a heavy dependence of Iran’s current cropping pattern on water-intensive species. The results highlight that horticultural crops, particularly nuts and fruits, consume more virtual water than field crops, while low-water-demand field crops exhibit slightly higher averages than low-water-demand horticultural species. These findings underline the urgent need for optimizing crop selection, improving irrigation management, and incorporating virtual water accounting into agricultural policy. Shifting production toward low-water-demand crops such as citrus, tomato, and cucumber could significantly enhance water productivity and contribute to sustainable resource management under climate change.