Articles
NUTRIENT MANAGEMENT FOR HIGH SOLUBLE SOLIDS PRODUCTION IN AUSTRALIAN PROCESSING TOMATOES
Article number
724_8
Pages
75 – 83
Language
English
Abstract
Apart from genetics, crop management can have a major impact on soluble solids (TSS) production in processing tomatoes.
The effects of crop nutrition (particularly N, P and K) on fruit soluble solids levels have been widely reported.
Still, Australian processing tomato growers do not have guidelines on how to manage a complete nutrition program under their production conditions to achieve high soluble solids levels in high yielding crops.
A survey, conducted in the 2001/02 season, established that the Australian industry has undergone a rapid transformation of production practices, led by the introduction of sub-surface drip irrigation in the 1990s.
A decline in grower numbers has been matched with expanding production areas per grower.
A major driver of these changes was the need to increase yield per hectare to maintain commercial viability.
Sub-surface drip irrigation has also led growers to change from fertiliser topdressing to fertigation.
It has also affected rotation practices.
Under drip irrigation, tomatoes are grown continuously for up to four years to make use of the high capital investment in irrigation infrastructure.
These changes coincided with an overall decline in soluble solids.
Fertigation technology allows exact irrigation and nutrition, and thus reliable quality, if inputs are monitored and managed to achieve established target levels.
The 2002/03 and 2003/04 seasons have been used to generate target nutrient levels for processing tomato petiole sap, and total nutrient uptake figures (accumulated nutrients) for major and trace elements.
In addition, TSS levels in first red fruit and petiole sap were investigated as early indicators of soluble solids development in tomato crops.
The aim was to ‘correct’ soluble solids levels in time for harvest, if the indicator showed that levels may be low and nutrient uptake was not balanced.
The effects of crop nutrition (particularly N, P and K) on fruit soluble solids levels have been widely reported.
Still, Australian processing tomato growers do not have guidelines on how to manage a complete nutrition program under their production conditions to achieve high soluble solids levels in high yielding crops.
A survey, conducted in the 2001/02 season, established that the Australian industry has undergone a rapid transformation of production practices, led by the introduction of sub-surface drip irrigation in the 1990s.
A decline in grower numbers has been matched with expanding production areas per grower.
A major driver of these changes was the need to increase yield per hectare to maintain commercial viability.
Sub-surface drip irrigation has also led growers to change from fertiliser topdressing to fertigation.
It has also affected rotation practices.
Under drip irrigation, tomatoes are grown continuously for up to four years to make use of the high capital investment in irrigation infrastructure.
These changes coincided with an overall decline in soluble solids.
Fertigation technology allows exact irrigation and nutrition, and thus reliable quality, if inputs are monitored and managed to achieve established target levels.
The 2002/03 and 2003/04 seasons have been used to generate target nutrient levels for processing tomato petiole sap, and total nutrient uptake figures (accumulated nutrients) for major and trace elements.
In addition, TSS levels in first red fruit and petiole sap were investigated as early indicators of soluble solids development in tomato crops.
The aim was to ‘correct’ soluble solids levels in time for harvest, if the indicator showed that levels may be low and nutrient uptake was not balanced.
Authors
D. Blaesing, A. Murray, M. Schulz, M. Stewart
Keywords
fruit yield and quality, brix, petiole sap nutrients, nutrient uptake
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