Interactions between the water and nitrogen economies of crops
Shortage of both water and nitrogen are widespread in the Australian cropping regions. The effects of water and nitrogen on biological processes relevant to agriculture (e.g. soil nitrogen mineralisation, photosynthesis) can be additive, synergistic or antagonistic. Research with an exclusive focus on water or nitrogen risks overlooking synergies and trade-offs, hence the need for explicit consideration of the links between the economies of water and nitrogen in crops and cropping systems. This report has two chapters. In Chapter 1, we review the literature on water and nitrogen interactions from physiological, agronomic, economic, breeding and modelling perspectives. In Chapter 2, we present new information from modelling studies assessing the economic value of three sources of information for decision making: initial soil nitrogen, initial soil water, and seasonal rainfall forecast.