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Root impact on the stability and types of micro‐
aggregates in silty soil under maize
Author(s) -
Watteau F.,
Villemin G.,
Burtin G.,
JocteurMonrozier L.
Publication year - 2006
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.2005.00734.x
Subject(s) - humus , rhizosphere , soil structure , bulk soil , soil science , chemistry , soil horizon , organic matter , root system , soil organic matter , soil water , agronomy , environmental science , biology , genetics , organic chemistry , bacteria
Summary We wished to assess the impact of maize roots on the stability, nature and formation of soil organomineral aggregates under field conditions. We sampled coarse‐textured soil, cropped with maize for 3 years, and combined in situ study of the root system with evaluation of soil structural stability. We examined root morphology (i) on thin sections of still recognizable root tissues, and (ii) at the interfaces between roots and soil, using transmission electron microscopy (TEM) to differentiate between fine and coarse roots. Soil structural stability was evaluated in relation to a spatial gradient of increasing distance from the roots. For that we distinguished between soil adhering to roots and that not adhering in the rhizosphere, and soil between the rows of this crop, and used two methods of granulodensimetric soil fractionation involving different disaggregation strengths. We isolated and identified the organomineral associations in the soil fractions determining soil stability. We found that the roots at the soil–root interface generated stable aggregates of 2–20 µm size, which were much involved in the structural stability of the soil adhering to roots. We identified by TEM several types of organomineral associations that depended on the nature of the plant or microbial organic matter. The distribution of the different types of aggregates varied according to their positions in relation to the roots. We showed that humification of roots contributes significantly to the development of stable organomineral associations in the soil.