Agriculture Reference
In-Depth Information
Box 3.1
(continued)
unit (fig. B3.1.2). Positively charged sesquioxide films on the flat surfaces also act
as electrostatic bridges between clay crystals or form complexes with negatively
charged organic polymers. These arrangements all contribute to the excellent
structural stability of soils such as Krasnozems (Ferralsols in the World Soil
Classification; see appendix 1). Krasnozems are important viticultural soils in parts
of southeastern Australia.
Figure B3.1.2
Edge-to-face flocculation of
kaolinite clay crystals (White
1997). Reproduced with
permission of Blackwell
Science Ltd.
Kaolinite
crystals
Figure 3.4
Diagram of a
macroaggregate (White
1997). Reproduced with
permission of Blackwell
Science Ltd.
Macroaggregate
(>250
m)
Microaggregate
(< 250
m)
Domains, silt grains
Fine roots
(5-60
m)
and fungal hyphae
