Scientists have recognized the potential for plants to influence organic matter dynamics and the possibility that such effects can feed back to influence plant productivity. However, research to date has been somewhat limited in its focus, dealing primarily with microbial decomposition of fresh litter. Here I discuss examples of ways that focus might be expanded to provide a more complete picture of potential plant-soil feedbacks. First, substrate lignin and nitrogen concentrations have been considered primary controls of litter decomposition. However, other aspects of substrate chemistry may be paramount in systems where decomposition is mediated by soil fauna, particularly if decomposer fauna have unique nutritional requirements. For example, research on tree-soil interactions in systems with abundant calciferous earthworms indicates that tree species with tissues rich in calcium may promote rapid decomposition because of the high calcium requirements of earthworms. The importance of substrate nutrients other than nitrogen may be underappreciated because of the heavy reliance on litter-bag methods that likely favor microbial over faunal decomposition in decomposition studies. Second, studies of the influence of plants on organic matter dynamics in soil mineral horizons should consider the myriad ways that organic matter can be protected from decomposition through interactions with mineral surfaces. While commonly measured plant traits, such as lignin, may be important in influencing biochemical recalcitrance of soil organic matter, other traits may be important in influencing chemical and physical protection of organic matter in mineral soils. For example, variation among plant trees in the cycling of polyvalent cations can have consequences for stabilization of organic matter onto mineral surfaces, thereby influencing soil carbon stocks. Other plant traits are likely important in influencing physical protection of soil organic matter. Thus, a broader view of plant species effects on organic matter dynamics will allow better understanding of the influence of management decisions and global change factors that alter plant species composition on biogeochemistry and soil fertility.