Humus formation

Humulo-cbinon, n. humuloquinone. -hydro-cbinon, n. humulohydroquinone. Humus-bildung, /. humus formation, -decke, /. covering of humus, -erde, /. humus hu-moiis soil,... 

Long-term grasslands provide plenty of organic matter for humus formation. If the soil is not acidic or waterlogged, the soil fauna and flora create humus and the subsequent useful development of a porous crumb and granular structure. Porosity encourages root growth and the uptake of soil nutrients. 

V. Carbohydrate Transformation in Chemical Processes, Including Humus Formation... 

In some chemical processes, including natural humus formation, non-enzymic carbohydrate transformation, in aqueous media, into noncarbohydrate products is important. 

Figure 2.5. Schematic representation of the modified lignin theory of humus formation. Adapted with permission from Stevenson, F. J. (1994). Humus Chemistry Genesis, Composition, Reactions, 2nd ed. John Wiley and Sons, New York.

Martin, J. P., and Haider, K. (1971). Microbial activity in relation to soil humus formation. Soil Sci. Ill, 54-63. 

Martin, J. R, and Haider, K. (1980). Microbial degradation and stabilization of 14C-labeled lignins, phenols, and phenolic polymers in relation to soil humus formation In Lignin Biodegradation Microbiology Chemistry and Potential Applications, Vol. II. Kent-Kirk, T., Higuchi, T., and Chang, H., eds., CRC Press, Boca Raton, FL, pp. 77-100. 

Haynes R. J. (1986) The decomposition process minerahzation, immobilization, humus formation, and degradation. In Mineral Nitrogen in the Plant-Soil System (ed. R. J. Haynes). Academic Press, Orlando, pp. 52-126. 

Humus formation Internal Direct Indirect Production of gut enzymes that favor the condensation reactions Biosynthesis of waxes, etc. Production of enzymes that favor humification by gut symbionts... 

Modem Views of the Origin and Nature of Humic Substances Biochemistry of Humus Formation... 

Diptera occur in soil mostly at their larval stages, only rarely as an adult insect, which is usually without wings. Their larvae require quite a lot of moisture, some are able to burrow in the soil, but usually they use already existing tunnels and holes. They eat living and dead plants, residues of animals, excreta, fungi, etc. Some species are parasites on worms, molluscs or another insect. Their major effect on soil consists in speeding up degradation processes and the support of humus formation. 

The soil fauna play such an important role in humus formation that any reasonably complete discussion of soil organic matter and its effect on plant growth must deal with them. In the limited space available the author will refer briefly to the chief types of animals involved, mention some of the main factors that determine their abundance, and consider the role that they play in soil formation and crop production. 

From the standpoint of soil humus formation, slugs and snails are of considerably less importance than are earthworms, because most of their activities are confined to the soil surface. They carry little of the vegetation into the soil beyond the upper one or two inches. 

SOIL ANIMALS, HUMUS FORMATION AND CROP PRODUCTION ... 

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