C. Vernon (Colorado State University, Ft. Collins, Colorado, USA) Cole & E. T. (Colorado State University, Ft. Collins, CO, USA) Elliott 
Soil Organic Matter in Temperate AgroecosystemsLong Term Experiments in North America [PDF ebook] 

The presence – or absence – of soil organic matter (SOM) has important implications for agricultural productivity. It could also have significant implications for global climate due to its role as a source/sink of carbon. Therefore, it is important to understand the issues related to the accumulation or loss of SOM, to use what we have learned from experiments to make sound decisions about soil and crop management, and to test models and future concepts concerning SOM management. A database is included with the book, presenting tabular data for 34 sites in North America.
Soil Organic Matter in Temperate Agroecosystems discusses all of these issues and more, answering such questions as: