23 Lec 23 Soil - I Humus formation and characteristics 1 Humus formation 2 Humus characteristics a Composition b Chemical fractionation c

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: I. Humus formation and characteristics 1. Humus formation 2. Humus characteristics a. Composition b. Chemical fractionation c. Humus-clay complexes b. Adsorptive properties 3. Beneficial properties imparted to soil by humus II. Composting Reading : Textbook: Sylvia et al., 2004. Chapter 13 (pages …) and Chapter 23 (pages 587-598) Soil Organic Matter Soil Organic Matter 3: Humification and Composting 3: Humification and Composting Plant Residues Soil Biota Humus *Decomposition *Humification *process *Recycling Carbon Dioxide *Respiration (oxidation) Decomposition Sequence Humus http://virtual-museum.soils.wisc.edu/som/index.html • Brown to black colored • Very large molecules (MW: 2,000-300,000 g/mol) • Relatively stable, complex, polymeric Humus Formation From Sylvia et al., Principles and applications of soil Microbiology. • Least understood aspect of SOM chemistry • Precursors are enzymatically produced/altered • Synthesis: condensation into larger molecules Humus Composition • Phenolic units (50%), polysaccharides (20%), and proteins (20%) • 58% C, 3-6% N; C/N/P/S ratio: 100/10/1/1 • < 50% of its structural composition are known • Age of soil humus: 150- 1500 years • = fulvic acids + humic acids + humins Humus Composition Light yellow Yellow brown Dark brown Grey- black Black Fulvic acid Humic acid Humin Humic substances decrease in degree of solubility...
View Full Document

This note was uploaded on 04/02/2010 for the course ESPM 131 taught by Professor Pallud during the Spring '10 term at University of California, Berkeley.

Page1 / 28

23 Lec 23 Soil - I Humus formation and characteristics 1 Humus formation 2 Humus characteristics a Composition b Chemical fractionation c

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online