Dynamics of moisture storage and temperature in the of dark gray forest soil profiles under Phlox paniculata plantations

Abstract

The research goal was to study the seasonal features of the thermal and water regimes of the soil in the phlox agrocenosis under the conditions of the high Altai Region’s Ob River area. The soil cover was represented by dark gray forest soil. It was characterized by a light loamy particle-size composition. The temperature measurements showed that the end of May and the first days of June 2024 were characterized by high soil temperatures. From August 01, there was temperature decrease. There was no freezing of the soil in winter, as the snow cover was set before severe frosts. On December 01, the soil temperature at a depth of 5 cm was 1.0°C, and at a depth of 60 cm it was 2.0°C. By December 21, it decreased by one degree, and then remained unchanged until the end of February. In the spring of 2025, the stationary state of the temperature field persisted until April 01. The accumulated temperature during July and early August 2024 remained constant (66-68°C). The autumn was very warm. In the first ten-days of December, the temperature gradually decreased and reached two degrees by the end of the month, after which it stabilized until spring. In the first ten-days of June 2024, the moisture content in the root zone was at the field capacity level. However, in the second ten-days of the month, rainfall increased the moisture content to 15% of the soil weight. In the third ten-days of July, the soil moisture content decreased dramatically. In the humus horizons, it dropped below the withering moisture content. In general, there was a lack of moisture from the end of July to the middle of August, so the flowers required watering in the amount of 200 to 250 m³ ha. In 2025, during the first half of the growing season, the flower crops were in the conditions favorable for their growth and flowering but during the second half, they required irrigation.