Anaerobic soil disinfestation impact on soil nutrients dynamics and nitrous oxide emissions in fresh-market tomato

Anaerobic soil disinfestation (ASD) is proposed as a pre-plant, non-chemical soil disinfestation technique to control several soilborne phytosanitary issues. Limited information is available on the impact of ASD on soil fertility, plant growth, and potential nutrient loss. The objectives of the current study were to evaluate the effects of ASD applied using composted poultry litter (CPL) and molasses as amendments, on soil redox potential, pH, temperature, soil nutrient content, plant biomass and nutrient accumulation, and nitrous oxide (N₂O) emissions. A field study was conducted on fresh-market tomato (Solanum lycopersicum L.) at two sites, Immokalee and Citra, FL, comparing ASD applied using a mix of CPL at the rate of 22 Mg ha⁻¹ and two rates of molasses [13.9 (ASD1) and 27.7 m³ ha⁻¹ (ASD2)] as a carbon-source to chemical soil fumigation (CSF). ASD treatment had a significant impact on soil redox potential, but did not affect soil pH or temperature. Soil treatment did not affect nitrous oxide emissions from intact polyethylene mulched beds at either location. Emissions ranged from 0 to 0.378 μg m⁻² h⁻¹ and from 8.8 to 39.8 μg m⁻² h⁻¹ in Immokalee and Citra, respectively. However, on day 21 after punching holes in the polyethylene film to transplant, N₂O emissions ranged from 1.56 to 4.83 and from 303.4 to 1480.1 μg m⁻² h⁻¹ in Immokalee and Citra, respectively. Emissions were higher in ASD than in CSF plots in Citra, but not in Immokalee. Molasses and CPL used in ASD treatments increased soil nutrients content, and particularly the availability of P and K. Results show no clear evidence of an increased risk of N loss with ASD compared to CSF. However, pre- and post-planting nutrient management should be adjusted to take into account the nutrients provided through the molasses and CLP application.