IRRIGATION PROPERTIES OF WATERS AND THEIR VARIABILITY ON THE EXAMPLE OF WATER BODIES OF ODESA REGION

Abstract

The purpose research consists in improving the method of assessing the danger of irrigation salinization of the soil based on the indicator of the amount of toxic salts in chloride ion equivalents (DSTU 2730:2015) and in testing the proposed method in assessing the variability of irrigation water properties. Methods. The analysis of the empirical material for the presence of gross errors, the determination of the statistical characteristics of the series of observations and the parameters of the laws of distribution of water quality indicators was performed using the methods of mathematical statistics. Results. The article is a continuation of the research published in the previous issue of the journal "Agrarian Innovations" No. 16. In accordance with the purpose of the research, the evaluation of the irrigation properties of water in the work was carried out according to the improved methodology of DSTU 2730:2015 according to the e(rCl–) criterion, other criteria were not considered. The article proposes a detailed typification of irrigation waters based on O.A. Aly-okin's typification of natural waters, improvement of the methodology of DSTU 2730:2015, and a probabilistic approach in assessing the quality of irrigation waters. Based on the improved methodology, an assessment of the risk of soil salinization during irrigation with waters of the Sarata River, Kuchurgansky and Baraboy reservoirs was performed. For each water body, based on the results of observations, the values of the indicator e(rCl–) were calculated, the parameters of the laws of its distribution were established, and the probability was determined (the duration of the total time period in fractions of the warm period of the year (WPY)) of the water quality class for different types of soils. It was established: for sandy and loamy soils, the waters of the Sarata River in its lower part belong to the I or II class of irrigation waters for 40–50% of the WPY, from 50 to 90% of the WPY, the waters are unsuitable for irrigation (class III) for all types of soils; for sandy and sandy soils, the waters of the Sarata River in its upper part belong to class I for 90–95% of WPY, class I or II for 90–99% of WPY for sandy, sandy, light loamy and medium loamy soils; even for clay soils of the I or II class within 70% of WPY; the waters of the Kuchurgan reservoir for sandy and loamy soils during 80–85% of WPY belong to class I soils, and to class I or II – 85–95% of WPY; for light and medium loamy soils up to class I or II – 80–90% WPY; for heavy loam and clay up to class I or II – 60–75%; for clay soils up to class III – 40%; According to the e(rCl–) indicator, the waters of the Baraboy Reservoir are suitable for irrigation of all types of soils (class I) during the entire WPY. Conclusions. During the TPR, the composition and properties of water change, therefore, when classifying the quality of irrigation water, it is advisable to determine the probability of quality classes. According to the e(rCl–) indicator, the waters of the Sarata River (Bilolissya village) are practically unsuitable for irrigation of all types of soil. In the upper part of the Sarat River (Menyailivka village), the irrigation properties of the waters are significantly improved: for sandy, sandy loam, light loam and medium loam soils, they belong to the I or II class during 90–99% of the WPY. Water requires a careful approach when watering most types of soil. The waters of the Kuchurgan reservoir are similar (but a little worse) to the waters of the Sarat River (Menyailivka village): for sandy, loamy, light- and medium-loamy soils, I or II class during 80–95% of WPY; for clayey soils, the waters belong to I or II classes within 60% of WPY. These waters require a careful approach when watering lightly and moderately permeable soils. According to the e(rCl–) indicator, the use of the waters of the Baraboy Reservoir during the WPY is possible for irrigation of all types of soils without restrictions.