Temporal variations of the hydraulic conductivity characteristic under conventional and conservation tillage

Kreiselmeier, Janis, Chandrasekhar, Parvathy, Weninger, Thomas, Schwen, Andreas, Julich, Stefan, Feger, Karl-Heinz and Schwärzel, Kai, (2019). Temporal variations of the hydraulic conductivity characteristic under conventional and conservation tillage. Geoderma, 362 1-12

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  • Sub-type Journal article
    Author Kreiselmeier, Janis
    Chandrasekhar, Parvathy
    Weninger, Thomas
    Schwen, Andreas
    Julich, Stefan
    Feger, Karl-Heinz
    Schwärzel, Kai
    Title Temporal variations of the hydraulic conductivity characteristic under conventional and conservation tillage
    Appearing in Geoderma
    Volume 362
    Publication Date 2019-12-26
    Place of Publication Amsterdam, Netherlands
    Publisher Elsevier Inc.
    Start page 1
    End page 12
    Language eng
    Abstract Conservation agriculture promotes as one of its three key principles the reduction of tillage intensity to minimize soil physical disturbances. The choice of tillage system alters hydraulic conductivity at (Ks) and near saturation. Drier regions of the hydraulic conductivity characteristic (HCC) may be affected as well. Temporal variations of the HCC along with water retention characteristics of tilled soils have come into the focus of researchers in recent years. It was shown that it may be preferable to account for such variations in soil water modelling. Here, the effects of a conventional tillage (CT), reduced tillage (RT) and no tillage (NT) system on the HCC were investigated on an experimental field with a Haplic Luvisol in Eastern Germany throughout part of a winter wheat growing season. This included changes following agricultural management such as stubble breaking and seedbed preparation. Hood infiltrometer measurements were conducted in the field and transient evaporation experiments in the laboratory were performed on undisturbed soil cores to describe the HCC over a wide range of pressure heads (h) from saturation to −1000 cm (pF 3). On tilled plots, Ks and hydraulic conductivity at h = −2 cm (K−2 cm) were more variable with time than observed spatial variability. Overall, Ks was significantly (p < 0.05) higher under RT compared to NT while for CT they ranged in between. Correlation and multiple linear regression indicated a distinctly different soil structure between tilled and untilled treatments. While bulk density and macro-and mesoporosity could explain some variability in Ks and K−2 cm on CT and RT, it was meaningless for the untilled soil. A denser soil matrix on NT with few conducting macro-and biopores was attributed to those findings. Under tillage, the loosened soil matrix and decaying organic matter mixed into the topsoil likely govern water transport at and near saturation. Over the entire HCC, variability decreased with drier conditions on NT while this was less pronounced on tilled soil, especially RT, indicating that tillage may affect not only soil macroaggregates but also the soil matrix. In this specific case, variability of the HCC with time was shown to be large for tilled plots, and modeling of soil water may benefit from an explicit consideration of these changes. Contrasts in soil structure under tilled and untilled soil should also be reflected in the future development of pedotransfer functions for the prediction of (near-) saturated K. Different soil physical property predictors may be needed for a valid estimation.
    Keyword Hydraulic conductivity characteristic
    Hood infiltrometer
    Soil structure
    Copyright Holder Elsevier B.V.
    Copyright Year 2019
    Copyright type All rights reserved
    DOI 10.1016/j.geoderma.2019.114127
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    Created: Fri, 31 Jan 2020, 01:08:57 JST by Eric Siegmund on behalf of UNU FLORES