Nitrogen mineral soil horizons

A. Adsorption of Dissolved Organic Carbon and Dissolved Organic Nitrogen in Mineral Soil Horizons 53... 

Dissolved organic nitrogen also shows some reduction in mineral soil solution relative to the organic soil horizon. Although few data are currently available for mineral soil solution DON concentration and flux, DON reduction in mineral soil is comparable to that of DOC (Fig. 5). 

The effects of five phenolic compounds, catechol, protocatechuic, p-coumaric, p-hydroxybenzoic, ferulic acids and their mixture were studied on pH, organic matter, organic-nitrogen, total phenolic content and certain inorganic ions of forest mineral soils (Ae and B horizons). The A- and B-horizon soils, were amended with 104 M concentration of each phenolic compound and their mixture. In general, soil properties were affected by phenolics amendement. However, soils amended with catechol did not influence any of the soil characteristics. Contents of organic matter, nitrogen and phosphate were lower in soils amended with different phenolic compounds compared to the unamended control soil (Inderjit and Mallik, 1997). 

Kaiser, K. Zech, W. (2000a) Sorption of dissolved organic nitrogen by acid subsoil horizons and individual mineral phases. Fur. J. Soil Sci. 51 403-411... 

Much emphasis has been placed on the plowed layer and its contribution to crop production, and comparatively little research has been done on the subsoil. In fact, in general discussions of the depletion of soil fertility the subsoil is often ignored, even though we know that it is often higher in essential nutrients, other than nitrogen, than is the A-horizon. These mineral nutrients may be less available to plants than those in the surface layer that is constantly subject to weathering and oxidation, but nevertheless subsoils do contribute in a major way to plant feeding. The plowed layer is only 6—12 inches deep whereas the subsoil tapped by the root system may have a depth of several feet. 

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