1. Significance of soil organic matter to soil quality and health -- 2. Soil organic matter management strategies -- 3. Soil organic matter fractions and their relevance to soil function -- 4. Stimulatory effects of humic substances on plant growth -- 5. Suppression of soilborne diseases in field agricultural systems : organic matter management, cover cropping, and other cultural practices -- 6. Contributions of fungi to soil organic matter in agroecosystems -- 7. Connecting belowground and aboveground food webs : the role of organic matter in biological buffering -- 8. Tillage and residue management effects on soil organic matter -- 9. Strategies for managing soil organic matter to supply plant nutrients -- 10. Soil and crop management effects on soil microbiology -- 11. Interactions among organic matter, earthworms, and microorganisms in promoting plant growth.