Yu. V. Aksenova
The studies were aimed at assessing the current reclamation state of the long-irrigated meadow-chernozem soil used in a vegetable crop rotation. Indicators of soil fertility were determined by generally accepted methods. From 2001 to 2017, humus content in irrigated soil stabilized at an average level of 5% in the layers of 0–20 cm and 20–40 cm. Humus consisted of mainly humic acids, the share of which varied from 45.0% to 54.0%. Their amount did not change under the influence of irrigation. Fractions were redistributed within the groups of humic acids. Under regular long-term irrigation, the content of the fraction of free humic acids in the soil became very low (7.2–9.9%); the content of the acids associated with calcium was average (22.9–27.3%); the content of the acids associated with the mineral part of the soil was high (13.2–19.7%). In the composition of humus, the amount of the fraction of free fulvic acids increased. The type of humus remained stably fulvate-humate, with a ratio of carbon humic acids to fulvic acids of 1.5–1.7. The energy potential of the soil organic matter was at a critical level – from 2143 gJ/ha to 2243 GJ/ha. Under the influence of irrigation, the amount of exchangeable magnesium in the composition of the soil-absorbing complex gradually increased against the background of an increased sodium content (5–7%). In the aggregate composition of the soil, agronomically valuable fractions accounted for 45.0–59.9%, but the aggregates were not resistant to the destructive effects of water. Long-term irrigation contributed to the development of secondary salinization. Against the background of the lack of fodder grass cultivation and the use of organic fertilizers, it led to the deterioration in the quality of soil aggregates, structural state of the soil as a whole, and insufficient content of labile humic acids in the organic matter of the soil.
Keywords: irrigation; humus; humic acids; structural and aggregate composition; labile organic matter.
Author Details: Yu. V. Aksenova, Сand. Sc. (Biol.), assoc. prof. (е-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.).
For citation: Aksenova Yu. V. Agroecological State of Meadow Chernozem Soil under Long-Term Irrigation // Dostizheniya nauki i tekhniki APK. 2019. Vol. 33 No. 12. Pp. 15–19 (in Russ.). DOI: 10.24411/0235-2451-2019-11203.