The Assessments On The Impact Of The Climate Change On Maize Growth In Northeastern China

The impact of climate change on the growth of maize in Northeastern China was examined using the temporal and spatial analysis of agricultural climate resources during the period of 1961-2006. Based on the maize growth simulation model, the growth sub-model was improved by treating the carbon dioxide concentration as an input variable of the model. Then the impact of future climate change on the growth of maize in Northeastern China was studied using the improved model. It is extremely helpful to policy maker and international environmental agreements.The primary conclusions are as follows:(1) Northeast China is one of the most affection areas by climate change. Based on the meteorological observation data in the growing season from 1961 to 2006, the result showed that Northeast China has some climatologically characteristics, including sharply increased temperature and the decrease of precipitation and the sunshine hours. Specifically, the detailed results were:(a) the temperature range became bigger from south to north in Northeast China, and the tendency become increasingly significant since 1981. (b)The spatial tendency of the precipitation was different, but the decrease trend was not obviously. (c)The sunshine hours in the most stations were decreased; the range became bigger from southeast to northwest. (2) By the contrast of simulated and observed development days, the simulated error was 1 to 3 days. Through the adjustment and validation of the applicability, the original model could simulate the leaf area index and dry weight of organs well, which is applicable in northeast China. (3) To consider the impact of the climate change and fertilization effect on the growth and development of maize in northeast china comprehensively, the growth sub-model at production level 1 was modified. Then the improved model was used to simulate the maize yields respectively in the following 3 programs:(a) considering only the photosynthesis, (b) considering only the transpiration, and (c) considering both the photosynthesis and transpiration. By comparative analysis, simulated yields all rise in the three programs, when the carbon dioxide concentration increased The response of transpiration and the increase of the yield to the increased CO2 are both more significant and larger than that of program B. (4) The yield of maize would reduce under A2, B2 scenarios without considering CO2 fertilizer effects. With CO2 direct effects, CO2 fertilization effect may offset negative impacts of climate change on maize yields. (5)Appropriately adjusting sowing data and introducing new varieties all can improve maize yield effectively.