FUNDAMENTAL SCIENTIFIC RESEARCH WORK ON VEGETABLE GROWING IN PLANT-GROWING STRUCTURES IN THE USSR
From the point of view of economic solution of engineering and construction problems of hotbed and greenhouse construction the southern regions have the advantage. Building constructions there are considerably lighter owing to the small snow accumulations as a result of which their cost diminishes.
The sharp reduction in the envisaged temperature difference cuts heating costs and the comparatively high mean temperatures of the outside air and the considerable solar radiation curtail the expenses for heating the plant-growing structures.
Based on these investigations, a suggestion was put forth to combine the development of vegetable growing in the open with that in hotbeds and greenhouses in the South with a view to supplying the more northern regions with vegetables. In recent years numerous investigations were carried out to perfect the hydroponic method of growing vegetable crops. Cultivars have been chosen, schemes worked out for the size and configuration of the nutrient area, substrates selected, the technology of using the substrates and solutions is being developed and specified. This progressive method of raising vegetable crops ensures the production of 18–20 kg/m2 cucumbers, 8–14 kg/m2 tomatoes and cuts labour input by 17–40 per cent.
The collaborators of the Institute for Vegetable Growing studied the root nutrition of cucumber plants grown in hotbeds on artificial medium. It was found that during the first year the use of keramsite as a substrate