CLIMATE-CHANGE-INDUCED TEMPORAL VARIATION IN PRECIPITATION INCREASES NITROGEN LOSSES FROM INTENSIVE CROPPING SYSTEMS: ANALYSIS WITH A TOY MODEL

Abstract

<List> <ListItem><ItemContent><p>● A simple model was used to evaluate how increasing temporal variability in precipitation influences crop yields and nitrogen losses.</p></ItemContent></ListItem> <ListItem><ItemContent><p>● Crop yields are reduced and nitrogen losses are increased at current levels of precipitation variability.</p></ItemContent></ListItem> <ListItem><ItemContent><p>● Increasing temporal variability in precipitation, as is expected (and observed) to occur with anthropogenic climate change will reduce yields and increase nitrogen losses further.</p></ItemContent></ListItem></List></p> <p>A simple ‘toy’ model of productivity and nitrogen and phosphorus cycling was used to evaluate how the increasing temporal variation in precipitation that is predicted (and observed) to occur as a consequence of greenhouse-gas-induced climate change will affect crop yields and losses of reactive N that can cause environmental damage and affect human health. The model predicted that as temporal variability in precipitation increased it progressively reduced yields and increased losses of reactive N by disrupting the synchrony between N supply and plant N uptake. Also, increases in the temporal variation of precipitation increased the frequency of floods and droughts. Predictions of this model indicate that climate-change-driven increases in temporal variation in precipitation in rainfed agricultural ecosystems will make it difficult to sustain cropping systems that are both high-yielding and have small environmental and human-health footprints.

Keywords

• crop yield|fertilizer timing|nitrogen loss|precipitation variability|toy model