Formation of thermophysical properties of dark-gray forest soil under Phlox paniculata plantations in the Altai Region’s Ob River area

Abstract

Phlox paniculata is a perennial flower crop; selective breeding with this flower has been carried out at the Research Institute of Gardening in Siberia named after M.A. Lisavenko since its foundation. The primary advantage of phloxes is their luxuriant and long flowering. Nevertheless, the thermal properties and microclimate of the soil under plantings of flower crops on variety testing sites are understudied. In this regard, we have defined the research goal and organized the studies of the thermophysical properties and water-thermal regime in the genetic horizons of dark gray forest soil under the plantings of the phlox variety Rumyanets Devushki. The thermal state of the soil is determined by its temperature, thermal capacity, thermal conductivity and thermal diffusivity as well as heat flows arising in its profile. At the same time, these properties are determined by the agrophysical soil indices as moisture content, density, dispersion, temperature and organic matter content. In this case, the maximum impact is exerted by the particle-size composition (conservative substance) and moisture content (dynamic component of influence). In general, the thermophysical profile of the dark gray forest soil in the summer of 2023 remained stationary throughout the observation period. It should be noted that in the first half of the growing season of 2024, there was virtually no precipitation, but August and early autumn were rainy. As a result, the soil horizons were saturated with moisture, especially in the underlying horizons B and BCk where the degree of moistening was almost twice as high as the lowest moisture capacity. As a result, the volumetric thermal capacity of the soil in September increased 2.3 times compared to the absolutely dry state, and the thermal conductivity increased 3.6 times. Thermal diffusivity decreased by 33% only.