ABSTRACT
This chapter discusses greenhouse gas emissions from soils of tropical agroecosystems within the contexts of total agricultural sources and anthropogenically created radiative forcing of climate. It provides a perspective of the relative importance of both agriculture and soils of the tropics to the climate change issue. The relative impact of different anthropogenically generated greenhouse gases on radiative forcing of climate can be assessed by multiplying the global warming potential index of a gas by its source strength. The issue of indirect effects of methane (CH4) is especially important to assessment of agricultural contributions to climate forcing because agriculture is a major contributor to anthropogenic emissions of this gas. The predominant agricultural sources of CH4 are ruminant animals and flooded rice, with smaller amounts associated with animal waste. Rice based cropping systems are perhaps the most complex with respect to emissions of trace gases from soils and the rice paddy is very difficult to manage in terms of nitrogen efficiency.
