The Soil Moisture during Dry Spells Model and Its Verification

Abstract

<jats:p>The objective of this study was the development and verification of a model of soil moisture decrease during dry spells—SMDS. The analyses were based on diurnal information of the occurrence of atmospheric precipitation and diurnal values of soil moisture under a bare soil surface, covering the period of 2003–2019, from May until October. A decreasing exponential trend was used for the description of the rate of moisture decrease in six layers of the soil profile during dry spells. The least squares method was used to determine, for each dry spell and soil depth, the value of exponent α , which described the rate of soil moisture decrease. Data from the years 2003–2015 were used for the identification of parameter α of the model for each of the layers separately, while data from 2016–2019 were used for model verification. The mean relative error between moisture values measured in 2016–2019 and the calculated values was 3.8%, and accepted as sufficiently accurate. It was found that the error of model fitting decreased with soil layer depth, from 8.1% for the surface layer to 1.0% for the deepest layer, while increasing with the duration of the dry spell at the rate of 0.5%/day. The universality of the model was also confirmed by verification made with the use of the results of soil moisture measurements conducted in the years 2009–2019 at two other independent locations. However, it should be emphasized that in the case of the surface horizon of soil, for which the process of soil drying is a function of factors occurring in the atmosphere, the developed model may have limited application and the obtained results may be affected by greater errors. The adoption of calculated values of coefficient α as characteristic for the individual measurement depths allowed calculation of the predicted values of moisture as a function of the duration of a dry spell, relative to the initial moisture level adopted as 100%. The exponential form of the trend of soil moisture changes in time adopted for the analysis also allowed calculation of the duration of a hypothetical dry spell t, after which soil moisture at a given depth drops from the known initial moisture θ0 to the predicted moisture θ. This is an important finding from the perspective of land use.</jats:p>

Which index is better for assessing the success of reclamation: Naturalness or hemeroby?

“…Soil aeration indicators increase during reclamation for all lithozems and do not change in pedozems. The overall trend of aeration growth cannot be recognized as favorable due to the risks of soil hyperaeration and excessive soil moisture loss (Biniak-Pieróg et al, 2020). The increase in aeration can be explained by the influence of abiotic processes of swelling and shrinkage, which result in cracking of monolithic pads and formation of aggregates.…”

Sustainable Innovation: Turning Waste into Soil Additives

“…Wrocław is located in SW Poland, in the moderate climate zone. The annual precipitation in Lower Silesia is between 560 and 600 mm [ 37 , 75 ].…”

Mesoclimatic Analysis of Non-Precipitation Periods in Lithuania

“…The water balance of soil is mainly determined by the amount of precipitation and the intensity of evaporation, which becomes particularly significant during long periods without precipitation. They involve intense drying of the soil profile, which may lead to meteorological drought and, subsequently, soil drought (Gomboš et al, 2019;Biniak-Pierog et al, 2020). Processes in which the soil absorbs moisture directly from the atmosphere can only partially compensate for the lack of precipitation (Dawid & Janik, 2018).…”