ABSTRACT
Africa’s development depends heavily on soil ecosystem services. However current soil
degradation coupled with increasing pressure on land is threatening the soil resource base.
There is an urgent need to establish soil health surveillance systems to guide investments and
monitor trends in soil health status and impacts of interventions. Surveillance systems require
appropriate and rapid, low cost methods that directly measure soil functional properties and
can be applied at larger scale. Spectroscopic methods that directly measure organic and
mineral composition hold promise for fulfilling this role. Infrared molecular spectroscopy
(IR) is one method that has shown promise for predicting many soil functional properties. Xray
diffraction spectroscopy (XRD) is another promising method, which directly determines
soil mineral composition, but has been little researched as a tool for quantitative prediction of
soil functional properties. However a comprehensive knowledge of soil mineralogy in Africa
is lacking due to poorly and fragmentally coordinated scientific investigations coupled with
the limitations in the traditional analytical techniques. The aim of this study was to develop a
rapid XRD measurement protocol and evaluate the ability of X-ray diffraction technique to
rapidly predict soil functional properties based on mineral composition. Geo-referenced
samples associated with the Africa Soil Information Service (AfSIS), taken from a set of 10
sentinel sites randomized over sub-Saharan Africa, were used for characterization. A total of
160 topsoil samples taken from 16 randomized points of ten 100-km2
sites: Tanzania (3 sites),
Malawi (2 sites), Mali (1 site), Burkina Faso (1 site), Kenya (2 sites) and Ghana (1 site) were
characterized for chemical properties, particle size distribution, engineering properties and
bulk mineralogy. Variation of the mineralogy within and between sites was explored using
principal component analysis using the R statistical software, as a precursor to exploring
relationships with directly measured soil properties and soil fertility diagnostics. The
clustering of individual minerals and the distributions of the soil fertility variables identified
across the sites appeared to relate to differences in mineralogical functional groups,
supporting the hypothesis that mineralogical data could be used to predict functional
properties. The findings therefore suggest opportunity for improving soil assessment using
information on soil mineralogy. For instance XRD information on mineralogy can be
combined with information from soil physico-chemical properties, to provide powerful
diagnostic capabilities, for low cost and rapid prediction of soil functional properties. Further
work should aim to develop direct quantitative predictive relationships between soil
functional properties and mineralogical composition using the full set of AfSIS reference
samples.
NYAMBURA, K (2021). Characterization Of Soil Mineralogy In Relation To Soil Fertility Functional Properties For Selected Countries In Africa. Afribary. Retrieved from https://track.afribary.com/works/characterization-of-soil-mineralogy-in-relation-to-soil-fertility-functional-properties-for-selected-countries-in-africa
NYAMBURA, KAMAU "Characterization Of Soil Mineralogy In Relation To Soil Fertility Functional Properties For Selected Countries In Africa" Afribary. Afribary, 01 Jun. 2021, https://track.afribary.com/works/characterization-of-soil-mineralogy-in-relation-to-soil-fertility-functional-properties-for-selected-countries-in-africa. Accessed 05 Nov. 2024.
NYAMBURA, KAMAU . "Characterization Of Soil Mineralogy In Relation To Soil Fertility Functional Properties For Selected Countries In Africa". Afribary, Afribary, 01 Jun. 2021. Web. 05 Nov. 2024. < https://track.afribary.com/works/characterization-of-soil-mineralogy-in-relation-to-soil-fertility-functional-properties-for-selected-countries-in-africa >.
NYAMBURA, KAMAU . "Characterization Of Soil Mineralogy In Relation To Soil Fertility Functional Properties For Selected Countries In Africa" Afribary (2021). Accessed November 05, 2024. https://track.afribary.com/works/characterization-of-soil-mineralogy-in-relation-to-soil-fertility-functional-properties-for-selected-countries-in-africa