PARENT SESSION
Contributed Oral Session 165: Agroecology: Diversity and Modeling
Friday, August 12, 8:00 AM - 11:30 AM, Meeting Room 521 A, Level 5, Palais des congrès de Montréal

Modeling rice and wheat crop NPP in Mainland China: Present and future.

Yongqiang, YU¹, Yao, HUANG, Wen, ZHANG, ¹ Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing

ABSTRACT- China is one of the most important countries cultivating rice and wheat crops. According to the FAO statistical data, the rice cropland acreage and yields in China are about 21% of the world rice cropland area and 33% of the world rice yields respectively; the relevant number of wheat is 13% and 18%. Simulating rice and wheat NPP in a national scale is important to food security and environmental diplomacy of China. Traditional crop simulation model based on the process simulation of crop growth is normally site-specific. For computing the carbon fixation in a national scale, crop NPP is necessary to calculate using model with spatial data. To address the spatial variability, a new methodology for national estimation of crop productivity is proposed. This methodology integrates a site-specific model with a Geographic Information System (GIS). With the integration of GIS, crop simulation model can be extended to the application of national level. By linking spatial databases to crop simulation models, crop NPP from Chinese rice and wheat in 2000 is simulated with a daily step. The ArcGIS software package was used for all of the GIS needs, including the data access, the projection definition, the overlaying of different vector layers, the creation of grids by converting vector data, and the conversion of data between grid and ASCII formats. Validation of the crop simulation model was conducted at different spatial scales, i.e. site scale (data from papers) and national scale (data from statistics) in China. Simulated results showed that at both resolutions level crop yield have a good agreement with the observed values. The global climate change data was provided by B1 and A1T scenarios from IPCC. The GIS-based crop simulation model is run for scenarios of future climate to predict the effects of climate change on rice and wheat crop yields in China. Results show the climate change will be particularly benefit on the agriculture productivity in China, especially in North China. There are also a number of source uncertainties that can be listed in this study, such as uncertainties in the climate change scenarios, reliabilities about the input data, and deficiencies in fertilizer volume data in a country scale. Hence, it is necessary to assess model uncertainty at the national scale in the future.

Key words: rice wheat, crop simulation models, GIS, climate change