THE EFFECT OF SUPPLEMENTAL ASSIMILATION LIGHTING WITH HPS AND LED LAMPS ON THE CUCUMBER YIELDING AND FRUIT QUALITY IN AUTUMN CROP

Abstrakt

The aim of the study was to evaluate the effect of HPS and LED assimilation lighting and LED interlighting on the yielding and as cucumber fruit quality in autumn cultivation cycle. The possibilities of increasing the density of plants due to the use of LED technology were also assessed. The study was conducted in three compartments: I with HPS top light only; II with top light HPS + 2 line LED interlight, III with 100% LED, top LED + 2 line LED interlight. Light level was in every compartment kept at the level of ~320 µmol m^–2 s^–1. PAR. The number and weight of cucumber fruits were investigated. The harvest was carried out every day. To assess the harvest quality for the plants grown in the two terms fruits were then examined for the chemical quality attributes of cucumber fruit, such as the content of total soluble solids (TSS), total sugars (TS), ascorbic acid and nitrate (NO₃) P, K and Ca. Another part of fruits was subjected to sensory analysis performed with the scaling method. The cucumber grown in the autumn growing cycle gave higher yield and the quality of fruits produced appeared more balanced for the plants lighted with HPS+LED or 100% LED as compared to the traditional, overhead HPS lighting. The above, together with the results from the rate of buds’ abortion assessment seem to legitimate the increase in the cucumber crop density when applying LED lighting.