Modeling impacts of air pollution, climate change and land management on crop productivity and yield in China’s agroecosystems during 1980-2005

Background/Question/Methods To understand the role of agriculture in global carbon budget and ecosystem services (e.g. food security), it is crucial to assess impacts of climate change, air pollution and land management on crop productivity. We developed and applied the agricultural module of the Dynamic Land Ecosystem Model (DLEM-Ag), which fully couples crop growth and major biogeochemical cycles at daily time-step and multiple spatial scales, to examine how crop productivity has changed as a result of changing climate, increasing air pollution and other environmental stresses. The DLEM-Ag model has been fully calibrated against field data sets from both China and North America, and then was applied in both site and regional levels.

Results/Conclusions The preliminary results show that substantial year-to-year variations in crop production were derived from seasonal and interannual climate variability; irrigation and fertilizer application were primary controls over crop yield increase; and the tropospheric ozone could lead to a mean reduction of 5-20% in crop productivity and yield varying among crop types, with the highest reduction rate (about more than 30%) in parts of rain-fed Mid-north China where experienced high ozone concentration and drought in the study period. Our simulation results indicate that practically the improvement of air quality and optimized land management could be an adaptation strategy for climate change, which could increase the crop production and consequently enhance the carbon sequestration capacity in China’s agroecosystems.