Evaluation of H2Grow as an alternative raised bed design for commercial vegetable production

Improving irrigation efficiency while sustaining crop productivity and nutrient use is important for resilient vegetable production. This study evaluated the H2Grow raised-bed system for its effects on root-zone soil moisture and temperature, irrigation water use, soil and plant nitrogen (N) dynamics, and bell pepper ( Capsicum annuum L.) productivity during the 2024 and 2025 growing seasons in northeast Mississippi. Treatments consisted of two bed types (H2Grow and conventional raised beds) and three N application rates (112, 168, and 224 kg ha⁻¹-N). H2Grow maintained greater soil volumetric water content and a slightly moderated root-zone soil temperature relative to conventional beds. System-level irrigation records indicated approximately 33% and 32% lower seasonal irrigation water use under H2Grow in 2024 and 2025, respectively. Soil NO₃⁻-N, NH₄⁺-N, and tissue N concentrations were influenced primarily by N application rate and growing season, with bed-type effects occurring only at selected sampling periods. Higher N rates generally increased soil and tissue N concentrations, total N uptake, and biomass accumulation, whereas nitrogen uptake efficiency (NUE) declined with increasing N rate and was lowest at 224 kg ha⁻¹-N. Fruit number was greatest at 168 kg ha⁻¹-N, while fruit fresh weight and wall thickness were not affected by N rate. Growing season significantly affected fruit number, fresh weight, and wall thickness, whereas no significant bed-type effects were detected for biomass, yield, fruit number, wall thickness, total N uptake, or NUE. Overall, H2Grow was associated with greater root-zone soil moisture and lower system-level irrigation requirements without significant reductions in bell pepper productivity. These findings support further evaluation of H2Grow as a potential water conservation strategy and alternative to conventional raised bed for commercial vegetable production systems.