• Contact Us
    • Send Feedback
    • Login
    View Item 
    •   Home
    • Journal and Journal Articles
    • Journal and Journal Articles
    • View Item
    •   Home
    • Journal and Journal Articles
    • Journal and Journal Articles
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    Whole Repository
    CollectionsIssue DateRegionCountryHubAffiliationAuthorsTitlesSubject
    This Sub-collection
    Issue DateRegionCountryHubAffiliationAuthorsTitlesSubject

    My Account

    Login

    Welcome to the International Institute of Tropical Agriculture Research Repository

    What would you like to view today?

    Mapping rootable depth and root zone plant-available water holding capacity of the soil of sub-Saharan Africa

    Thumbnail
    View/Open
    U18ArtLeenaarsMappingInthomNodev.pdf (2.799Mb)
    Date
    2018
    Author
    Leenaars, Johan G.B.
    Claessens, Lieven
    Heuvelink, Gerard B.M.
    Hengl, T.
    González, M.R.
    Bussel, Lenny G. J. van
    Guilpart, N.
    Yang, H.
    Cassman, Kenneth G.
    Type
    Journal Article
    Target Audience
    Scientists
    Metadata
    Show full item record
    Abstract/Description
    In rainfed crop production, root zone plant-available water holding capacity (RZ-PAWHC) of the soil has a large influence on crop growth and the yield response to management inputs such as improved seeds and fertilisers. However, data are lacking for this parameter in sub-Saharan Africa (SSA). This study produced the first spatially explicit, coherent and complete maps of the rootable depth and RZ-PAWHC of soil in SSA. We compiled georeferenced data from 28,000 soil profiles from SSA, which were used as input for digital soil mapping (DSM) techniques to produce soil property maps of SSA. Based on these soil properties, we developed and parameterised (pedotransfer) functions, rules and criteria to evaluate soil water retention at field capacity and wilting point, the soil fine earth fraction from coarse fragments content and, for maize, the soil rootability (relative to threshold values) and rootable depth. Maps of these secondary soil properties were derived using the primary soil property maps as input for the evaluation rules and the results were aggregated over the rootable depth to obtain a map of RZ-PAWHC, with a spatial resolution of 1 km2. The mean RZ-PAWHC for SSA is 74mm and the associated average root zone depth is 96 cm. Pearson correlation between the two is 0.95. RZ-PAWHC proves most limited by the rootable depth but is also highly sensitive to the definition of field capacity. The total soil volume of SSA potentially rootable by maize is reduced by one third (over 10,500 km3) due to soil conditions restricting root zone depth. Of these, 4800 km3 are due to limited depth of aeration, which is the factor most severely limiting in terms of extent (km2), and 2500 km3 due to sodicity which is most severely limiting in terms of degree (depth in cm). Depth of soil to bedrock reduces the rootable soil volume by 2500 km3, aluminium toxicity by 600 km3, porosity by 120 km3 and alkalinity by 20 km3. The accuracy of the map of rootable depth and thus of RZ-PAWHC could not be validated quantitatively due to absent data on rootability and rootable depth but is limited by the accuracy of the primary soil property maps. The methodological framework is robust and has been operationalised such that the maps can easily be updated as additional data become available.
    http://dx.doi.org/10.1016/j.geoderma.2018.02.046
    Multi standard citation
    Permanent link to this item
    https://hdl.handle.net/20.500.12478/3206
    Non-IITA Authors ORCID
    Lieven Claessenshttps://orcid.org/0000-0003-2961-8990
    Nicolas Guilparthttps://orcid.org/0000-0003-3804-0211
    Digital Object Identifier (DOI)
    http://dx.doi.org/10.1016/j.geoderma.2018.02.046
    IITA Subjects
    Soil Fertility
    Agrovoc Terms
    Root Zone; Soil Water; Soil; Crop Production; Fertilizers
    Journals
    Geoderma
    Collections
    • Journal and Journal Articles4842
    copyright © 2019  IITASpace. All rights reserved.
    IITA | Open Access Repository