Control of the concentration of the micro element of ferrum in the substrate when growing tomatoes in protected soil conditions

Abstract

Vegetable growing is one of the important branches of agriculture in Ukraine. Numerous scientific studies and the use of their results on practice proved that the use of fertilizers and irrigation in greenhouses can increase the yield of vegetable crops several times. The introduction of industrial cultivation technologies, which are based on full mechanization of the main production processes, reduction of water consumption, and the creation of varieties of cultivated plants with high potential productivity, can contribute to increasing the economic efficiency of vegetable growing. The problem of development and implementation of industrial technologies requires the solution of a whole series of complex tasks, which include: the creation and widespread distribution of varieties of vegetable crops suitable for mechanized harvesting; development of a set of agrotechnical measures, which includes norms, terms and means of applying fertilizers, irrigation regimes, measures to combat weeds, pests and diseases; studying the influence of weather conditions on the growth of crops, the formation of crops, comparison of agroclimatic resources of growing areas with crop requirements, etc. A characteristic feature of modern vegetable growing is its intensification by increasing the proportion of early vegetables in protected soil, application of fertilizers, etc. Tomatoes are one of the main vegetable crops grown in Ukraine. It is known that their harvests on the territory of Ukraine are very high variable and determined by the provision of the territory with light, heat, moisture, nutrients, as well as biological features of the culture. Many factors contribute to the increase in tomato yields, in particular introduction into the production of new, more productive varieties, varietal zoning, which provides for the placement of different prematurity varieties according to the agro-climatic resources of the territory and biological resources features of this culture. Identifying the reasons for fluctuations in the productivity of vegetable crops over time and across the territory, development on this basis quantitative indicators that would make it possible to characterize with sufficient accuracy the amount of crops depending on the weather conditions that occur in certain years in different regions — a rather complex problem that is solved in modern research on agrometeorology. Due to the frequent change in the varietal composition and the large number of varieties with different ripening periods, vegetable crops are a complex object for research. Although most tomatoes are grown in open ground, their cultivation in glass greenhouses or tunneltype greenhouses covered with plastic film is becoming more common to supply local markets with fresh fruit. Mostly tall varieties of tomatoes are grown in closed soil. They make it possible to use the area of greenhouses as efficiently as possible and obtain rich harvests. High concentrations of carbon dioxide (600–1000 ppm) are maintained in greenhouses to improve photosynthesis, growth rate, and yield. This practice is very common in low yield regions and intensive agricultural production systems. Although planting tomatoes in soil in tunnel-type greenhouses is still quite common, most intensive-type greenhouse tomato varieties are grown on substrates such as mineral wool. Fertigation provides adequate nutrient supply and eliminates most of the factors associated with heavy soil characteristics that are difficult to control. Growing tomatoes in greenhouses requires the use of a significant amount of water. To feed tomatoes, their producers also need to take into account the mass and degree of solubility of mineral fertilizers in water. Some elements or compounds present in irrigation water can affect the growth of plants, which is why there is a need to control their level. The paper investigates the effect of the concentration of the trace element ferrum in mineral wool substrate on the growth and development of the tomato variety Biorange (yellow fruits) during the period of mass fruiting in protected soil conditions. It was established that the photoelectrocolorimetric method for determining the content of the trace element ferrum in mineral wool hoods is quite sensitive, simple and recommended for use in serial analyses. The determined average value of the content of the trace element ferrum (1.23 mg/l) was found to be sufficient for growing tomatoes in the period of mass fruiting. Controlling the iron content allows you to significantly prevent tomato diseases such as leaf chlorosis and obtain high-quality crops.