Boron (B) is involved in important soil processes (Kovda 1973): the intra-soil biological cycle; humification; isomorphic substitution in clay minerals and the formation of colloids; and
illuviation. Goldschmidt (1937) found that B is concentrated in the uppermost humus layer of forest soils.
These sediments then undergo diagenesis under an anoxic and reducing conditions with subsequent sulfide production (similar to the process of
illuviation described by Fanning et al.
Similar observations were made for other irrigation treatments of this soil, and in some cases,
illuviation of micro-aggregates and clay particles was demonstrated by the turbid appearance of leachate for the clean water treatments.
In the Bw horizon of the Anthropic IBE there was a pattern of coalesced oxidic microaggregates, associated with features of incipient clay
illuviation (argillans) (Fig.
Observation using polarised microscopy, thin sections of a Lien-Hua-Chi (LHC) soil sample with fine texture indicated that in all argillic horizons, b-fabrics might be attributed to strong
illuviation of clay.
The dramatic difference in soil texture between the sites is likely to have also resulted in differences in water-holding capacity, nutrient status, bioturbation rates,
illuviation rates, oxygen diffusivity, litter quality, root penetration resistance, and net primary productivity.
Cutans are prominent in many of the profiles, indicating
illuviation from overlying horizons in the past and present (Vepraskas et al.
Our results suggest that differences in [K.sub.G] of different clay fractions may also be implicated in clay
illuviation and soil genesis.
Instead, the presence of parna (Butler 1956), and the
illuviation argillans on the sands, suggest that the area has been receiving dust.
The features most important for the classification are the presence of E horizon and abundance of clay
illuviation features.
The dominance of forest vegetation in this region does not help matters as SOM and nutrients are recycled downwards through
illuviation unlike in grass land vegetations.
This soil was classified as Eutric Fluvic Arenosols with weak features of
illuviation process development and sand and clay contents of 70.5-86.4% and 0.3-2.6%, respectively.