187 Effect of Nutrient Source on Quality and Yield of Strawberry Grown in Verticillium-infested Soil
Verticillium albo-atrum, a cosmopolitan pathogen that causes wilt of strawberry, can cause economic losses for growers and increased prices for consumers. This study was conducted in 1998 to assess the impact of organically and inorganically supplied N on fruit yield and quality. `Allstar' (resistant) and `Raritan' (susceptible) varieties of strawberry were planted in V. albo-atrum-infested soil that was amended with poultry compost (organic N) or ammonium nitrate (inorganic N). Fruit quality was assessed as titratable acidity (TA), soluble solids content (SSC) using a refractometer, and reducing sugars concentration using a gas chromatography. Disease incidence was below threshold level and did not affect the results of this study. Plants grown in compost amended plots produced an average of 41 fruit, weighing 354 g, compared to the 34.5 fruit weighing 487 g that were harvested from the inorganically amended plots. TA was not affected by the treatments. Overall, yield of `Raritan' was 40% greater than that of `Allstar'. The SSC of `Allstar' was highest in fruit that were produced in compost-amended soil in contrast to that of `Raritan', which was greatest for plants that were grown in the inorganically amended plots. Fruit grown in the inorganically amended plots generally had a higher concentration of glucose and fructose, but sucrose was found only in fruit from the control plots. Poultry compost may be an alternative source of N for producing strawberries but this needs to be further evaluated because of the slower release of nutrients over time.