Reclamation features of the hydrothermal regime of dark gray forest soil under iris plantations in the Altai Region’s Ob River area

Abstract

In order to collect more information about the flower crops growing in the Arboretum of the City of Barnaul, the research goal was to study the water and temperature conditions forming in the cenosis of bearded irises (Iris × germanica). In this regard, it was necessary to experimentally control the moisture content and temperature in the root layer of the soil. The temperature regime in the summer of 2024 had its own peculiarities. At depths of 5.10 and 20 cm, the temperatures ranged from 1.0-1.5°C during the entire observation period. At the same time, at a depth of 60 cm in the first half of June, during a cold snap, they turned out to be lower than in the upper part of the profile by 3-5°C. During July, this difference increased to 8-10°C, and by early August, it returned to previous values. In autumn, from September 1 to November 21, the course of temperature curves in the humus layer was the same at all depths ranging from 2 to 4°C, and only in the second ten days it dropped sharply from 23 to 3°C. In winter, from December 21, 2024, to February 21, 2025, the temperature at the studied depths remained stable and equal to +1°C. It should be noted that the winter of 2024-2025 was very warm. In the summer of 2024, the available moisture storage in the root layer of the soil was quite sufficient for the growth of irises. On July 10, the available moisture storage was 1 mm, on August 17, the shortage of available moisture storage (23 mm) appeared in the 0-50 cm layer which disappeared by the end of September. In 2025, the amount of atmospheric moisture in the soil was less than on the previous year. From July 15 to August 8, there was a shortage of plant available water. By the end of the growing season, the amount of available moisture storage was 20-25 mm in a layer of 0-50 cm.