Albedo of the soil cover as a factor of the temporal dynamics of readily available soil moisture in the technosols of the Nikopol manganese ore basin

The simulation of moisture content in Nikopol manganese ore basin technosols was performed using the Penman-Monteith approach and evaluate the role of the dependence of soils surface albedo from the humidity in the intensity of evapotranspiration. The sod lithogenic soils on loess-like loam and pedozem were chosen as the objects of the investigation. The research was conducted during 2012–2014 years at the investigation station of the remediation within Nikopol manganese ore basin (city Pokrov, Ukraine). The evapotranspiration from the soil surface was calculated by means of Penman-Monteith equation. Root zone moisture depletion is evaluated as the difference between soil water content at field capacity (pF = 2.3) and actual soil water content. The Ks value which is a water stress factor equals 1.0 as long as soil water content is higher than readily available water. If soil water content is lower than readily available water, Ks decreases linearly from one to zero according to total available soil water consumed. The soil water balance is performed in ISAREG with a daily time. The evaluation of readily available water content was carried out based on Penman-Monteith model taking into account meteorological data, technosols water-physical properties and the dependence of soil surface albedo on soil humidity. The color of the surface of the sod-lithogenic soil on the loess-like loam varies from yellow (2.5Y 4/2) in wet condition to yellow-red (10YR 6/5) in the dry condition. Albedo of this soil depended on the humidity varies in the range 0.17–0.31. The surface color of the pedozem varies from very dark gray (10YR 3/1) in wet condition to light-gray (2.5YR 6/2) in the dry condition. Albedo of this soil depended on the humidity varies in the range 0.10–0.31. There is a linear relationship between the moisture content in the soil and albedo of the soil surface. Albedo changes along with the humidity are most significant in the sod-lithogenic soils on loess-like loams. This is confirmed by the greatest regression coefficient. Albedo changes along with the moisture content are least significant in the pedozem. The distributionі of this index for different teсhnosols are characterized by a high level of similarity of shape due to the fact that the overall climate factors are crucial in shaping the dynamics of moisture. The distributions can be most good represented as a complex mixture of normal distributions. It was found that water supplies monitoring before the start of the growing season can provide valuable information necessary for the selection of crops for cultivation in the current year. The results indicate the urgency of measures to save the winter rainfall on the fields.