ASHS 2025 Conference

Maintaining soil health for open field and high tunnel (HT) production of vegetables has become prioritized by growers in recent years. In particular, there have been growing concerns about the sustainability of HT systems. Their hot and dry conditions, compounded by intensive practices, lead to challenges with soil temperature and moisture management, compaction, salinity, and ecosystem health. This report investigates how established and novel mulch types can help growers manage soil temperature, moisture, and health conditions across growing systems and climatic conditions. Tomato and lettuce trials were conducted from 2022 to 2024 in HTs and open-field plots to determine the effect of various mulch treatments (bareground, black plastic film, black woven fabric, paper mulch, white silage tarp and black silage tarp) on soil temperature, moisture, and health. Gravimetric and volumetric soil moisture content were determined weekly and bi-weekly in the lettuce and tomato trials, respectively. Soil temperatures were recorded at 10.2 cm depth throughout the growing seasons for both crops. EC, bulk density, and respiration data were collected at termination of all trials to assess soil health. In tomato, the application of black plastic mulch, fabric mulch, and black silage tarp was associated with higher average soil temperatures (23.7°C-28.9°C), compared to (22.4°C-26.8°C) under white tarp and paper mulch. In the lettuce trials, all mulch types retained soil heat in the early season (0.7°C-2.2°C) compared to bareground. The use of silage tarp maintained up to 21% more soil moisture than the bareground treatment for tomato and all mulches were effective at managing moisture loss. Limited effects on soil health criteria were observed, though higher measurements of bulk density and EC may be associated with increases in soil moisture. Results indicdate that mulch color and material affect soil temperatures and soil moisture in the summer, whereas in fall all mulches may reduce heat loss in the early period of the growing season and soil moisture (5-7%) in the late season. As growers address soil health concerns, an integrated approach will need to be adopted that utilizes multiple practices. This study shows that mulch color and type/material can be selected to alter the microclimate of the soil environment across production systems. More research is needed to determine how these impacts affect long-term soil health. The development of regional growing practices that ensure soil health will be instrumental to support a growing population and using mulches for vegetable production can help achieve this goal.