Study Of The Regional Impacts Of Climate Change On China's Grain Output

Intergovernmental Panel on Climate Change IPCC Fourth Assessment Report (AR4) objective,comprehensive and careful assessment of climate change existing and likely future impact.The observed evidence shows that it is likely that anthropogenic warming has had a discernible influence on many physical and biological systems.However,many of adaptation and the role of non-climatic factors impacts are difficult to identify.Food,fiber and forestry products are mainly distributed in the middle and high latitudes in the region.It is expected to increase a small amount of grain output if the average temperature increases by 1～3℃in the local.If the temperature exceeds the scope,the crop production of some areas will be lower.In the low-latitude areas,especially in the dry season in the tropics,even for a small increase in temperature(1～2℃),will also lead to reduced crop yields.From the global point of view,if the increase in the average temperature in the range 1～3℃,the potential food production is expected to increase with increasing temperature,and if more than this range,the food production potential will be reduced.Corn,as one of the important food,feed and energy crops in China and all of the world,the climate change impact on it directly related to our country's food security and energy strategy. Based on three research methods of the history of China's grain data statistical analysis,simulation of future corn production and corn field experiment observation, this paper reveals the impact of future of climate change on Chinese corn.First,this paper uses the data from "China Rural Statistical Yearbook" 1984-2003 of National Bureau of Statistics and the simultaneous annual temperature from the National Meteorological Centre meteorological information library of China Meteorological Administration.According to North China,Northeast China,East China and South China,Southwest and Northwest,China's mainland will be divided into six areas.This paper statistical analysis the temperature change,agricultural inputs and sow areas impact on grain production.Second,this paper selects the regional climate model(RCM) PRECIS exploited by the British Hadley Centre to simulate under different CO2 emission scenarios. With the two scenarios of IPCC SRES B2 greenhouse gas emissions and RCP 4.5 concentration stability,the RCM simulates the selected regional 50*50 km grid daily weather data.Then the grid in the future climate scenarios of B2 and RCP 4.5 under 90 years of the 2011-2100 daily weather data will be input into crop model CERES-Maize,and output the corn production every year under the two conditions. In addition,each scenario was divided into irrigation and rain-fed two situations.This paper has been selected 102 stations and analyzed impact of temperature and carbon dioxide on maize output statistically.Thereby,analysis of climate change in China's different regions and the impact on corn planted area.Third,through field experiments taken by randomized block design,each district area is 5m×6m,and select three maize cultivars tested in Zhongdan8, Zhongdan2996,Zhongdan14.The experiment was divided into three managements: on-demand watering whole growth period(water),mulching film of water(covered), not water(rain-fed),and was repeated these tests three times.In the samplings were done at seven key corn growing periods,and measured the activity indicators of superoxide dismutase(SOD),peroxidase(POD),malondial-dehyde(MDA), catalase(CAT).Through changes in the activity of the corn in the different treatment under the water,thus the text revealed adaptation to climate change of maize under drought conditions by giving the changes of the activity of the enzymes under different treatment instead of water usages.In this paper,the key findings are as follows:Temperature in China showed an upward trend between 1951 and 2003, particularly the mid-1980s.The rate of warming accelerates significantly.From 1998 to 2003,five in six years since 1951 were the warmest years,and the warming trend was significant at northern region.North China,Northeast and Northwest regions' warming is going to be 0.4 to 0.8℃/10 a,but the South region of the warming trend is less obvious than in the NorthAs a result of adopting right measures in northeast area,the climate warming has positive effect on crop production,and the production curve rises volatility.The reason is that when the temperature rises,the growing period of crop will become longer.So it is possible to adopt late-ripping and high-production maize,soybean, winter wheat and rice.The policies of crop cultivation have corresponding changes and the organism production will increase.Chilling injury affected crops are basically removed or reduced significantly.It is expected that the grain production of northeast have the potential of increasing production by temperature in the coming decades, agricultural production can be adjusted by changing cultivar and sowing period to offset the adverse effects of warming,and even benefit.The crop adaptation to temperature rising is relatively poor performance to effect crop yield among the areas of the North of China,Northwest and Southwest.The rising temperature accelerates crop growing,reduces the maturity period,and decreases the dry weight and ear weight.Except crop cultivar and genetic factors, climate of the area and characteristic of the geography affect crop production as well. Water-short is the key limiting factor on agriculture in the North China.To some degree,the climate change aggravates the situation of water-short.But in these areas, the increase of agricultural inputs and agricultural scientific and technological progress has played an important role on crop increase in the last 20 years.The crops reaction to temperature is not obvious in the East of China and the Central North of China.It shows that the crop is not sensitive to climate change and the potential adaptability is better.But the overall production decreases obviously in later time,which is related to the rapid economic development and fast decreasing of farmland and sown area in this two regions.It deserves further attention.In the coming 2011-2100,the temperature rises has a significant role in the northeast and north-eastern part of Inner Mongolia com.The effects of concentration of carbon dioxide on corn are different in the northeast region under different scenarios.The results showed that in the future northern spring maize region,maize yield will be significantly enhanced.Different rates throughout the production,about 15%to 29%.Increasing temperature has negative impact on the production of corn in most parts of North China.Rates vary throughout the production,about -5%to -28%.But it has the role of promoting corn in the central and southern Hebei,which is maybe the because of spring corn here in the north under the marginal growth zone.It still has a very strong warming space.Increasing the carbon dioxide concentration in a stable scenario,it will promote the growth of maize in the North China.But under the B2 scenario,it will not.The results showed that at the Huanghuai Plain spring sowing corn region in the future,maize yield will decline somewhat.With stable concentration,the higher the concentration of carbon dioxide in the area will promote the growth of maize.But under the B2 scenario,the higher the concentration of carbon dioxide has no role on it.The temperature rise will promote the yield of corn in mid-South of China,and the rate is about 5%to 7%.However,the increased concentration of carbon dioxide in mid-South of China did not promote the yield of corn.And integrated other factors which reduce output,it is shown that maize yield will decline at the rate of approximately 10%to 28%in the Southern Hills in the future.Under B2 scenarios,the higher of the temperature in the southwestern region will inhibit the growth of maize,and under the stable scenario,the higher the concentration of carbon dioxide in the southwest does not promote corn production. This shows that in the future the southwest hilly corn,the yield of corn will decline at the rate of about 12%to 20%.The higher of temperature inhibits the corn in most of the Northwest.It is shown that in the future of northwest inland corn zone,maize production will decrease in the rate of about 9%to 23%.The output in Gansu is likely to increase because in the north-western spring corn belt.According to Field Test,we can see that in three corn cultivars,Zhonagdan8 is the best in the drought resistance.In the key corn growing period,CAT,POD,SOD are for maximum performance.This shows that the Zhonagdan8,which has a best and strong protective enzyme system and under the dry conditions,physiological and ecological indicators of maize guarantee the plant's normal growth.The better one is Zhongdan14,the worst one is Zhongdan2996.So in the coming drought conditions, the corn cultivar in study should take Zhengdan8 as an example,or chose the similar cultivars.Coated ways will improve the efficiency of water use of corn,and the membrane is irrigated with water-saving irrigation techniques mulching the effective integration of technology.Coated ways mulching the warming effect of preserving soil moisture,and water-saving irrigation in the complementary role for maize growth has provided a suitable environment which is a needed and good measure to adapt to future climate change and drought.Especially in the early growth period of mulching maize,it has high soil moisture,suitable temperature,full corn emergence,robust growth,and a good root system which are giving a good foundation for the latter part of the growth of maize.For coated Corn,various stages are more harmonious.And growth period,dry matter accumulation and reasonable distribution are orderly.The coercion coefficient of the entire growth period is minimum,and the economic yield is maximum.