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Composition of tomatoes and tomato products in antioxidants (WG1) page 47
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Table 21. Main effect of increasing rate of phosphate fertilizer combined with nitrogen
and of increasing rate of nitrogen fertilizer combined with phosphorus on ascorbic acid
Fertilizer
treatment
concentration in tomato fruit juice (after Sharma and Mann, 1971)
Total soluble solids (%) Ascorbic acid (mg/100
ml juice)
Ascorbic acid (mg/kg
total soluble solids) (1)
Winter Summer Winter Summer Winter Summer
1963-64 1964 1965 1963-64 1964 1965 1963-64 1964 1965
30 P2O5 5.86 6.17 5.93 20.15 21.06 21.20 3438 3413 3575
60 P2O5 5.91 6.09 5.81 21.78 22.14 21.99 3685 3635 3784
90 P2O5 5.99 6.02 6.02 22.19 22.76 22.42 3704 3780 3724
P effect NS NS NS ** ** **
50 N 5.41 5.83 5.72 20.21 21.14 20.83 3735 3626 3641
100 N 6.14 6.13 5.94 21.60 21.67 21.86 3517 3535 3680
150 N 6.20 6.31 6.10 22.31 23.15 22.92 3598 3668 3757
N effect ** ** ** ** ** **
(1) added calculation
NS : non significant
** : significant at p = 0.01%
In tomato cultivated in sand pots, vitamin C content was reduced to one third in the
less sulphur (65 mg/kg) and nitrogen (70 mg/kg), and to half in -Mg (110 mg/kg), -K (114
mg/kg), -P (135 mg/kg) and -Ca (140 mg/kg) compared to control (210 mg/kg) (Dube and
Misra, 1975). In field experiments tomato fruit vitamin C content was significantly increased
by increasing levels of both nitrogen (up to 150 kg/ha) and phosphorus (up to 140 kg/ha), the
variation range being from 24 to 29mg/100ml juice (Patil and Bojappa, 1984).
Audisio et al.(1993) have cultivated tomato cv. Arletta in non heated greenhouse on
sandy-loam soil poor in organic matter. Organic fertilizing yielded a low production of fruit
rich in vitamin C (414 mg/kg fresh matter) while fertilizing with mineral or mineral + organic
fertilizer yielded a high production of fruit poorer in vitamin C (280 mg/kg fresh matter). In
glasshouse, Premuzic et al.(1998) have grown tomatoes cv. Platense on two substrates (pure
sand and peat-perlite) hydroponically irrigated with a complete nutrient solution and on two
organic substrates (100% vermicompost and 50% vermicompost:50% soil) irrigated with