MODELING LIGHT-ABSORPTION AND CANOPY NET PHOTOSYNTHESIS OF GLASSHOUSE ROW CROPS AND APPLICATION TO CUCUMBER

A model of light absorption and photosynthesis applicable to glasshouse row crops is constructed and applied to cucumber. Light absorption is calculated using a method suggested for discontinuous canopies; photosynthesis is modelled with a non-rectangular hyperbola. The predictions of this model are compared with experimental data in the preceding paper. Here the model is used to simulate responses to light and CO2 concentration and especially to examine the effects of varying the parameters of the crop that can be controlled by the grower. These include the number of plants in each row, the number and width of the rows, the gap between rows, and the height of the crop. For example, it is shown that, for high values of crop net photosynthesis, the number of rows is more important at high light than at low light, whereas crop height is more important at low light than at high light. The implications of these and other findings are discussed.