EFFECT OF FERTILIZERS ON FRUIT QUALITY OF PROCESSING TOMATOES

Abstract

Fertilizer research trials were conducted in tomato fields in Central California to determine the impact of slow release fertilizer on fruit quality and yield of processing tomatoes. Quality parameters evaluated were soluble solids content, color of a blended juice sample and total yield. Tomato yield was affected by soil type, type of fertilizer and variety used. Soluble solids content was affected by the different environmental or growing conditions in which the trials were conducted. Level of soil nutrition, type of fertilizer and cultural management of the tomato crop seem to have played a significant role on fruit quality and production. Slow release nitrogen fertilizer in combination with a potassium source fertilizer had a significant effect increasing soluble solids content (°Brix) in one of the sites. Furthermore, the addition of potassium + humic acid increased soluble solids in marginal tomato fields (poor soil types with low levels of residual nutrients). Yield response was similar to °Brix increases. Small yield differences were observed in what is considered good soils (deep sandy loam-class 1 soils). Poor to marginal fields, however, responded better to both yield and soluble solids which could benefit from the use of slow release fertilizers and justify their higher price over conventional fertilizers.