EFFECT OF NITROGEN AND POTASSIUM SUPPLY ON YIELD AND TISSUE COMPOSITION OF GREENHOUSE TOMATO

Does yield of greenhouse tomato benefit from supplemental nitrogen (N) and potassium (K) supplied in amounts greater than taken up by the plants? To answer this question, yield and fruit and leaf tissue composition were compared for tomato plants grown in rock-wool medium and supplied with sufficient N and K, or with N and/or K supply increased by about 30% over the control.
In 1999, supplemental N in the form of NH₄NO₃ decreased yield, a trend that became more obvious as the season progressed.
The K supply had no significant effect.
In 2000, supplemental N in the form of Mg(NO₃)₂ increased early yield and fruit size.
This effect disappeared later in the season.
The different response to supplemental N in the two years may be due to the effect of the form of nitrogen supplied on vegetative tissue.
An NH₄NO₃ supplement increased N in leaf or petiole tissue, more than an Mg(NO₃)₂ supplement.
Supplemental N did not affect composition of the fruit.
Supplemental K increased N and K in leaf or petiole tissue.
It did not affect K in fruit tissue but did decrease calcium in fruit in 1999.

International Symposium on Growing Media and Hydroponics

M.P.N. Gent

Lycopersicon esculentum Mill, ammonium, nitrate

https://doi.org/10.17660/ActaHortic.2004.644.49