Cover: The DSSAT model is widely used for simulating cropping systems in both the developed and less-developed world. However, originally DSSAT was developed for agricultural systems of North America where almost all nutrients for a crop are derived from fertilizers; in the developing countries, most are often low-input systems in which nutrients are derived from the decomposition of soil organic matter (SOM) and crop residues. A new SOM-residue module for simulating both C and N, which is based on the CENTURY model, has been added to DSSAT. See Gijsman et al., "Modifying DSSAT Crop Models for Low-Input Agricultural Systems Using a Soil Organic Matter-Residue Module from CENTURY," p. 462-474. Design by Julio Cesar Martinez, Graphics Art Department of CIAT.