Evaluation of soil structure and physical properties influenced by weather conditions during autumn-winter-spring season - Maja Bryk; Beata Kołodziej; Anna Słowińska-Jurkiewicz; Monika Jaroszuk-Sierocińska (2017)
Physical state of the upper soil layer is susceptible to external factors, including weatherconditions. It concerns in particular a soil without plant cover or mulching. Significant soilstructure transformations could arise especially due to the globally observed climate changewhich e.g. increases the possibility of extreme precipitation events. Therefore, we evaluatedthe seasonal changes of structure of the uncovered 0–5 cm soil layer and their effect on otherphysical properties in relation to precipitation and air temperature. Both the direct evaluationof soil structure by quantitative image analysis and the measurements of structure-dependentparameters as water and air contents and permeabilities were conducted to describe soilphysical state in detail. Soil samples were taken on 4 dates during the 2009/2010 season froma Haplic Luvisol developed from loess-like deposits. The largest alterations of soil structurewere detected in spring, after the soil had thawed completely and had been affected by theheavy and long-term precipitation. During the season soil structure transformed fromaggregate into non-aggregate one and the rearrangement of soil pore size distributionoccurred. Soil showed very high available water capacity and mostly medium saturatedhydraulic conductivity, but field air capacity and corresponding air permeability decreasedbelow values required for good plant condition. The total volume of pores correlatednegatively with precipitation and temperature. Actual water content was strongly positivelycorrelated with the precipitation amount shortly before sampling. There was no statisticallyvalid correlation between saturated hydraulic conductivity and precipitation or temperature.Furthermore, air permeabilities for selected groups of pores showed contrasting trends withprecipitation, dependent on the studied span of time. The temperature influenced the intensityof soil drying and freezing-thawing processes. Most of the identified alterations of soilphysical state could be attributed however to mechanical impact of rain which remodelledpores and solid phase in the studied soil layer.
Keywords: air and water permeability; pore and solid phase element size distribution; structure