Estimates of Tillage and Rainfall Effects on Unsaturated Hydraulic Conductivity in a Small Central European Agricultural Catchment

Abstract

In arable land, topsoil is exposed to structural changes during each growing season due to agricultural management, climate, the kinetic energy of rainfall, crop and root growth. The shape, size, and spatial distributions of soil aggregates are considerably altered during the season and thus affect water infiltration and the soil moisture regime. Agricultural topsoils are prone to soil compaction and surface sealing which result in soil structure degradation and disconnection of preferential pathways. To study topsoil infiltration properties over time, near-saturated hydraulic conductivity of topsoil was repeatedly assessed in a catchment in central Bohemia (Czech Republic) during three consecutive growing seasons, using a recently developed automated tension minidisk infiltrometer (MultiDisk). Seasonal variability of soil bulk density and saturated water content was observed as topsoil consolidated between seedbed preparations. Topsoil unsaturated hydraulic conductivity was lower in spring and increased in the summer months during two seasons, and the opposite trend was observed during one season. Temporal unsaturated hydraulic conductivity variability was higher than spatial variability. Cumulative kinetic energy of rainfall, causing a seasonal decrease in soil macroporosity and unsaturated hydraulic conductivity, was not a statistically significant predictor.

Aggregate and Particle Size Distribution of the Soil Sediment Eroded on Steep Artificial Slopes

“…This means that the particles before using ultrasound were coarser than those analyzed after its use. This proves that the eroded soil is clustered into the soil aggregates [18]. As the table presents all samples which were collected under different conditions (slope, initial condition), the particle size distribution curves of the samples without aggregates had less SD and were more consist than those with aggregates.…”

“…The infiltration of water through the soil aggregates is influenced by their spatial arrangement. The destruction of soil aggregates by rainfall leads to soil degradation and increased soil erosion [18]. The aggregate size distribution can be determined by using a laser diffractometer [19,20].…”

Special Issue “Soil Hydrology in Agriculture”

“…Thus, a major objective for soil scientists and hydrologists is to develop practical procedures for measuring SHP and their spatial distribution. The paper by Zumr et al [13] investigated the seasonal variability of the nearly saturated hydraulic conductivity of topsoil-due to agricultural management, climate, kinetic energy of rainfall and crop and root growth-by using an innovative automated tension minidisk infiltrometer. The main outcome was that the temporal k(h) variability was higher than the spatial variability.…”

Vlastnosti uměle generovaných srážek využívaných pro studium eroze půdy

“…Tyto empirické závislosti byly přejaty z literatury [21][22][23][24] a jsou běžně využívány pro odhad kinetické energie přirozeného deště i v podmínkách kontinentální Evropy (např. [25,26]). Z porovnání plyne, že kinetická energie simulovaného deště je nižší než kinetická energie přirozených srážek.…”