IRRIGATION AND NITROGEN MANAGEMENT AS THEY AFFECT FRUIT QUALITY AND YIELD OF PROCESSING TOMATOES

This study was designed to measure the effect of stress from three levels of irrigation during fruit development; with three different irrigation cut-offs during fruit ripening; and four rates of nitrogen, to find out the role each plays in yield, fruit peelability, percent solids, and viscosity.

Whole pack or diced tomato products are generally the most profitable part of the tomato business in California. Since whole peeled tomatoes utilize 25% of the raw product, 75% must be used as paste or juice. We cannot ignore management strategies that will maximize the paste yield.

Moisture stress during fruit development reduced yield and viscosity, did not significantly increase solids, but did increase peelable fruit. Irrigation cut-off before harvest (stress during fruit ripening) significantly increased solids and paste. The stress also decreased yields, viscosity, and peelable fruit.

The low nitrogen fertilizer rate of 57 kg/hectare reduced yield but there was no effect between rates of 168 kg/hectare to 392 kg/hectare. Nitrogen rates had no effect on solids or viscosity, but the 392 kg/hectare rate had significantly more peelable fruit than the 168 kg/hectare rate.