Abstract

The shift from traditional irrigation methods to pressurized irrigation has become essential, particularly considering the water scarcity in the US Southwest. In this context, this study evaluated the effects of different irrigation systems and rates on crop yield (Y) and water productivity (WP) within a multi-cropping system consisting of cantaloupe (Cucumis melo L.), broccoli (Brassica oleracea var. italica), and silage corn (Zea mays L.) under arid conditions in Arizona. Field experiments compared flood (F) and subsurface drip irrigation (SDI) systems at two crop evapotranspiration (ETc) replacement levels (100% and 80%), resulting in four treatments: F100, F80, SDI100, and SDI80. Seasonal total water applied (TWA), crop yield, water productivity, and silage corn forage-quality parameters were measured. The effects of irrigation systems varied among crops, whereas cantaloupe achieved the highest yield under flood irrigation, with maximum production observed in F100 (63.8 t ha−1). Meanwhile, cantaloupe yields declined under deficit irrigation and SDI treatments (57.2, 39.8, and 27.4 t ha−1 for F80, SDI100, and SDI80, respectively). In contrast, broccoli and silage corn generally performed better under SDI, where more frequent water applications might have improved root-zone moisture conditions and enhanced water productivity. Deficit irrigation substantially increased WP relative to full irrigation without significantly affecting yield for broccoli and silage corn. Broccoli WP ranged from 3.9 kg m−3 (F100) to 6.3 kg m−3 (SDI80), while silage corn WP increased from 8.7 to 8.8 kg m−3 under flood irrigation to 11.6–12.8 kg m−3 under SDI. Silage corn forage-quality parameters were not significantly affected by irrigation system or irrigation rate, indicating that moderate water deficits improved seasonal water use without compromising nutritive value. Overall, deficit irrigation reduced seasonal water use and improved WP, with the greatest benefits observed under subsurface drip irrigation. The results demonstrate distinct crop-specific responses to irrigation management, highlighting the necessity of customized optimization strategies. Moreover, our findings highlight that the SDI with moderate deficit irrigation (80% ETc) can provide an effective balance between water conservation and productivity, enhancing WP without compromising yield or quality under arid conditions.

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