PROPER PRE-HARVEST STRESS INCREASES PERCENT SOLIDS WHEN USING BURIED DRIP IRRIGATION IN PROCESSING TOMATOES

Buried drip irrigation was first used in California in the late 1980’s.
Drip irrigation resulted in considerable dollar savings where water costs are high and irrigation efficiency is low.
Tomato yields were higher when drip, rather than furrow, irrigation was used, but solids were lower.
Processors demanded solids of 5% or more, so drip growers tried the early water cut off used in furrow irrigation, with some increase in solids, but significant reduction in fruit quality and yields.
Trials in 1992 to 1995 were conducted at the West Side Research Center, using moisture reduction levels of 25%, 50%, and 75% of ET_c, 40 or 60 days before harvest vs no stress (110% ET_c) with a water cut off 10 days before harvest.
Data from these trials show that on a clay loam soil, reducing irrigation using 75% of ET_c 60 days before harvest, resulted in minimal yield loss and increased solids 25%, comparable or better than when using furrow irrigation.
More agressive ET_c reductions have increased solids as much as 6%, but yield losses are significant, up to 12 tons per acre.
Forty-day reduction was poorer than the 60-day.
Where processors are not paying growers for solids, the more moderate is used.

II International Symposium on Irrigation of Horticultural Crops

D.M. May, J. Gonzales

Subsurface irrigation, fruit quality, evapotranspiration, tomato

https://doi.org/10.17660/ActaHortic.1997.449.45