The yield of fruit vegetables is mainly dependent on the size,
harvest date and fresh weight of individual fruit at harvest, and
the total fruit fresh weight per plant. It has a strong influence on
the market price and economic benefit of fruit vegetable crop production.
Therefore, the market puts an increasing demand for an
accurate prediction of yields (Marcelis and Gijzen, 1998). Cucumber
(Cucumis sativus), as one of the main greenhouse crops in the
world, occupies 60–70% of total greenhouse area in China (Li and
Xiao, 2003). Like other fruit vegetables, cucumber shows a cyclic
growth pattern where periods of high fruit setting and slow fruit
growth alternate with periods of low fruit setting and rapid fruit
growth (Kato and Tanaka, 1971;Marcelis, 1992a). The seasonal fluctuation
of source/sink ratio is the main cause of this cyclic growth
pattern. How to control the cyclic growth pattern or the source/sink
ratio to achieve smooth and maximum yield is the problem faced
by cucumber crop management. Nitrogen has strong impacts on
leaf photosynthesis and dry matter partitioning. Therefore, optimization
of nitrogen management is one of the useful approaches
to control crop growth and source/sink ratio. For the optimization
of nitrogen management for cucumber crop production, it is essential
to quantify the effects of nitrogen on cucumber leaf and fruit
growth and yield.