Resource use dynamics and interactions in the tropics: Scaling up in space and time

We discuss the temporal and spatial dynamics of nutrient resources and water within cropping and livestock systems, their interactions and those with other resources such as labour. Short-term dynamics (within season) revolve around nutrient availability and losses as a function of soil moisture dynamics. Longer-term effects (multiple seasons and years) are related to residual effects of crop management in successive seasons and to changes in soil organic matter contents.