Impacts of Biofumigation and Anaerobic Soil Disinfestation on Strawberry Production

Due to the phase-out of methyl bromide, there is a need for alternative, nonchemical fumigation treatments in strawberry production. Anaerobic soil disinfestation and biofumigation are two non-chemical methods for controlling soilborne plant pathogens of strawberry. This study was designed to observe strawberry fruit nutrition and soil volatiles of a strawberry field being treated with biofumigation treatments, anaerobic soil disinfestation treatments, and a combination of the two alternative methods. A trial was conducted with 11 pre-plant soil-incorporated treatments arranged in a randomized complete block design with 6 rows (blocks). Biofumigation treatments consisted of deactivated mustard meal, deoiled mustard meal, mustard pellets, and Biofence mustard seed meal. Other treatments included dried molasses as a carbon source for an anaerobic treatment and a Basamid® chemical treatment. Additional combination treatments of deactivated mustard meal combined with molasses, deoiled mustard meal combined with molasses, and molasses combined with soybean meal (to lower amendment Carbon:Nitrogen ratio) were also applied, as well as an untreated control. Soil samples were taken at designated times post irrigation application in order to measure sinigrin and allyl isothiocyanate simultaneously. Harvested fruit were counted, weighed, and graded into marketable and non-marketable categories, and were then analyzed for sugars (fructose, glucose, and sucrose), organic acids (malic and citric), and mineral content (B, Na, Mg, P, S, K, Ca, Fe, Cu, Mn, and Zn). The combination of deoiled mustard meal and molasses can provide a comparable marketable yield as the chemical treatment Basamid®. Fruit sugar and organic acid content did not consistently differ among most treatments. Likewise, there were no consistent patterns of differences among treatments in mineral content of either fruit or leaf tissues. In general, the alternative methods of biofumigation and soil anaerobic disinfestation produced fruit of equal quality to that produced using the Basamid® chemical treatment. Future work will evaluate pathogen and soil nutrient dynamics affecting productivity in these alternative soil disinfestation treatments.