Increasing the effective use of water in processing tomatoes through alternate furrow irrigation without a yield decrease

Surface irrigation represents >85% of irrigated agriculture worldwide. Partial root zone drying (PRD) is a technique for improving crop water productivity (WP), and in practice can be applied as alternate furrow irrigation (AFI). A series of research station and on-farm trials were conducted in two consecutive years and three soil types to evaluate processing tomato crop performance under AFI vs every furrow irrigation (EFI). Crop growth and leaf gas exchange, fruit biomass and quality, soil moisture and water applied were evaluated, and changes in irrigation WP (WPi) determined in response to PRD. The AFI was consistent in maintaining fresh yields across cultivars and environmental conditions (i.e., years and soil textures) with at least 25% lower irrigation volumes than commonly applied under EFI. WPi increased by >29% and maintained fruit quality under AFI. Canopy growth was slightly lower, and a tighter plant regulation of stomatal conductance (gs) with only a small decrease in photosynthetic rates (Pn) was observed under AFI. Our results demonstrate that for California processing tomatoes AFI is effective in reducing agricultural water needs. Because of the extent of furrow irrigation worldwide, AFI can contribute to maintain highly productive agricultural land under production with lower water supply.