2017 ASHS Annual Conference

Methyl bromide and other soil fumigants have been heavily relied upon to control soilborne plant pathogens, nematodes, and weeds in polyethylene-mulched vegetable production in Florida. However, negative aspects of their use on the environment and human health have increased the interest in non-chemical, sustainable alternatives. Many of Florida’s vegetable production soils are generally sandy-textured, low in organic matter, nutrients, and water holding capacity, and therefore inherently low in fertility and highly leachable. Anaerobic soil disinfestation (ASD) is an emerging alternative to the soil fumigation model and is effective against soilborne pests in several crop production systems. Selection of optimal soil amendments and application rates is critical for successful application of ASD. Therefore, the objective of this study was to evaluate the effects of different soil amendments for ASD on cumulative soil anaerobiosis, plant growth, fruit yield, and postharvest quality of fresh-market tomato (Solanum lycopersicum L.). In the field experiment conducted during the fall of 2016 in Immokalee, FL, the six soil treatments included composted broiler litter (CBL, 11 Mg/ha) and molasses [(M, 6.9 m³/ha) ASD0.5], modified ASD with composted yard trimming waste (YTW) at the rate of 26.9 (YTW1+M) or 13.5 Mg/ha (YTW0.5+M), the Soil Symphony program (SSA, Terra Feed, LLC, Plant City, FL), composted YTW (26.9 Mg/ha) only (YTW1), and the combined application of YTW1 and SSA (YTW1+SSA). An untreated check (UTC), and chemical soil fumigation (CSF) treatment [Pic-Clor 60 (1,3-cichloropropene + chloropicrin) at the rate of 224 kg/ha] were used as controls. Excluding UTC, CSF, and SSA, all treatments received 5 cm of initial irrigation after polyethylene mulching and herbicide Reflex before polyethylene mulching. Cumulative soil anaerobiosis was higher in ASD0.5 compared to all the other treatments. Plant growth (stem, leaf, fruit) was greatest with ASD0.5 and the lowest in the UTC. Extra-large fruit yields resulting from all of the amendment treatments were equivalent to CSF and greater than the UTC. Total season marketable yields of CSF (78 Mg ha^-1), ASD0.5 (82 Mg ha^-1), YTW1+M (79 Mg ha^-1), YTW0.5+M (75 Mg ha^-1), and YTW1+SSA (76 Mg ha^-1), were greater than that of UTC (52 Mg ha^-1). Color and titratable acidity were the only fruit quality parameters influenced by soil treatments. Anaerobic soil disinfestation applied using alternative composted amendments and molasses can be a sustainable alternative to CSF producing comparable plant growth, marketable yield, and fruit quality.