The production of vegetables in a sheltered ground (i.e. in greenhouses) is currently one of the fastest growing and efficient agriculture industries, which aims to supply the population with fresh vegetables throughout the year.
Development and improvement of greenhouse production is closely interrelated with scientific and technical progress, which covers the entire process of vegetable crops cultivation, including the species and hybrids selection, irrigation and plant nutrition systems, creation of a biologically sound microclimate and its control, as well as cultivation technology.
The following modern technical solutions are used in the production:
- Drip watering system and the repeated use of the nutrient solution drainage.
One of the newest trends of greenhouse production both abroad and in our country is hydroponic vegetable cultivation. Currently, it is the main commercial process for obtaining high yields in greenhouses.
Hydroponic method of growing vegetables in a sheltered ground found international recognition in many countries, and was further developed as a low-volume method of growing plants on various substrates.
- “Ebb and flood” irrigation system of the plant area.
The use of specialized plant area in the greenhouse complexes allows using industrial technology for growing vegetable crop seedlings in order to obtain high-quality, uniform seedlings and reduce their production cost due to the mechanization of planting, watering and handling process.
- Wet pad cooling and post-humidification systems.
In addition to the screen system, wet pad cooling and post-humidification systems are used to reduce the air temperature in greenhouses (fogging) during the summer season. An important condition of this system is to create a certain pressure to produce the atomization (droplet diameter of less than 10 mkm). Due to the evaporation of moisture from the air, the relative humidity increases; this has a favorable effect on plant transpiration and promotes good growth, development, and increased yield.
- Carbon dioxide plant nutrition system.
The content of carbon dioxide in greenhouses has a special significance for the growth and development of plants, because it affects the photosynthetic rate. Under natural conditions, the concentration of carbon dioxide in the air is in the range of 300-400 ppm. Upon its increase up to 700-1100 ppm, the photosynthetic rate also increases, resulting in the improved yields of vegetable crops. Therefore, carbon dioxide nutrition of plants should be an integral part of farming throughout the growing season, beginning with the cultivation of seedlings; special emphasis should be made on the use of carbon dioxide plant nutrition during the flowering and fruiting, which greatly ensures high crop increment.
The most promising source of carbon dioxide supply for modern greenhouse production is waste gases from the boiler stations that use natural gas as fuel; natural gas does not contain sulfur and other contaminants.
- Assimilation lighting system.
Depending on the physiological characteristics, most vegetables efficiently grow and bear fruit with illuminance of 15,000-20,000 lux. Such powerful light energy flux is observed during sunny weather from March to August.
The low intensity of natural light in the autumn and winter period without an additional source of artificial supplementary lighting prevents the greenhouse cultivation of vegetable crops. The latest technology known as photoculture is based on the creation of all the necessary microclimate conditions using artificial supplementary lighting as the main source of light.
Optical radiation energy is a powerful factor that influences the growth and development of plants. When arranging lights in a greenhouse, the design parameters of the greenhouse must be taken into account.