Articles
LATE-SEASON DEFICIT IRRIGATION IS A RELIABLE TOOL FOR SOLUBLE SOLIDS IMPROVEMENT IN DRIP-IRRIGATED PROCESSING TOMATO PRODUCTION
Article number
724_6
Pages
61 – 65
Language
English
Abstract
Soluble solids concentration (SSC) is an important quality factor for processing tomatoes (Lycopersicon esculentum Mill.). The use of drip irrigation often results in undesirably low SSC. The effects of late-season deficit irrigation on fruit yield and SSC was investigated in 5 commercial, drip-irrigated field trials in 2004. In each field the grower’s irrigation regime was compared to a treatment receiving 25-50% less water over the final 4-7 weeks before harvest, a period corresponding to fruit ripening.
In all fields the growers utilized a deficit irrigation strategy, applying only 32-67% of reference evapotranspiration (ET°) over this period, averaging 53%; the reduced irrigation treatment varied from 20-46% of ET°), averaging 38%. Across fields, the grower irrigation regimes averaged 147 t ha-1 total fruit yield and 5.5 °Brix.
The reduced irrigation treatment reduced total fruit yield by only 6 t ha-1, and a corresponding increase in SSC resulted in no net loss of Brix yield (yield x °Brix). Fruit sampling throughout the ripening period confirmed that the SSC of late-maturing fruit was significantly increased by deficit irrigation, but that the SSC of early-maturing fruit was not increased by stress imposed after they had ripened.
We conclude that processing tomatoes can tolerate significant late-season moisture stress without loss of Brix yield, and that late-season deficit irrigation provides a flexible tool for fruit SSC management.
SSC monitoring of ripening (pink stage) fruit can help determine the severity of late-season deficit irrigation required to achieve desirable fruit SSC.
In all fields the growers utilized a deficit irrigation strategy, applying only 32-67% of reference evapotranspiration (ET°) over this period, averaging 53%; the reduced irrigation treatment varied from 20-46% of ET°), averaging 38%. Across fields, the grower irrigation regimes averaged 147 t ha-1 total fruit yield and 5.5 °Brix.
The reduced irrigation treatment reduced total fruit yield by only 6 t ha-1, and a corresponding increase in SSC resulted in no net loss of Brix yield (yield x °Brix). Fruit sampling throughout the ripening period confirmed that the SSC of late-maturing fruit was significantly increased by deficit irrigation, but that the SSC of early-maturing fruit was not increased by stress imposed after they had ripened.
We conclude that processing tomatoes can tolerate significant late-season moisture stress without loss of Brix yield, and that late-season deficit irrigation provides a flexible tool for fruit SSC management.
SSC monitoring of ripening (pink stage) fruit can help determine the severity of late-season deficit irrigation required to achieve desirable fruit SSC.
Authors
T.K. Hartz, P.R. Johnstone, M. LeStrange
Keywords
Lycopersicon esculentum, irrigation management, evapotranspiration, soluble solids
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