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Fig. 2. SEM fabrics in structural units of A soil horizon samples. From irrigated terraced cropland within the Xerepts environment: a) compacted subangular blocky aggregate with fissures at the interfaces of smaller units; b) surface fabric of previous aggregate, packing of plate shaped particles, well cemented; c) internal fabric of previous aggregate, reticulum of clusters, each formed from laminar particles and concentrically cemented to a central pore of 10 to 20 µm. From rainfed old cropland within the Xerepts environment: d) compacted granular aggregate; e) surface of previous aggregate, sand and silt particles with face-face joins; f) interior of previous aggregate, porosity of 10 µm generated by face-face and face-edge joins of silt-size phyllosilicates without cements. From thyme scrub land within the Xerepts environment: g) granular microaggregate composed of skeleton grains (silt size <50 µm) without apparent bonds. From oak and evergreen–oak woodland within the Xerepts environment: h) set of granular microaggregates constructed with skeleton grains (silt size) joined by organic cements and clustered around roots. From planted pine forest within the Cryepts environment: i) fine crumb aggregate ordered in smaller structural units pressed by abundant fungal hyphae; j) structural detail of previous aggregate, mycelium enveloping a group of silt-sized particles with clayey matrix and cements. From mature juniper shrub within Cryepts environment: k) aggregate composed of well cemented microaggregates, between whose weakness planes pores for the transmission of water (>30 µm) can be seen; l) detail of the internal fabric of the previous aggregate, silt particles joined by clay and edaphic cements forming layers and partitions.
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