Analysis Of The Relationship Between Main Climatic Factors Evolution Tendency And Yield Of Early Rice Of Chaozhou

Climate of Guangdong Chaozhou is a typical subtropical monsoon.Chaozhou meteorology station(116°63’E,23°67’N) is located in the southeast coast with the high altitude10.8m and in the center of Chaoshan plain with a wide range of typical and representative.Chaozhou meteorology station is located in the center of the Chaoshan plain with area of over4000square kilometers,which is the second largest plain and major grain producing areas in Guangdong.To research the region’s climate change impact on yield of early rice has important practical significance.The impact of climate change on agriculture,especially in agricultural production of southern China is more important.The research based on Chaozhou meteorology station’s climate data from1980to2011,and Chaozhou agricultural meteorology station’s early rice data from1980to2009,it chooses early rice of double cropping as the research object,The rate and trend of climate was analyzed by climatic liner trend method;Characteristics of interdecadal variations were analyzed by anomalies and anomaly percentages;The mutation of climatic variation was analyzed by the Mann-Kendall test and the moving t test;Periodic variation of climate characteristics of the region was analyzed by wavelet; According to the trend of the yield of early rice trends from1980to2009, the regression imitation model was adopted.The trend of climate change in21st century was analyzed by CMIP3data,and the trend of the yield of early rice in21st century was analyzed by year as well.The main conclusions are summarized as follows:(1)The mean temperature of the region from1980to2011was22.2℃,which has an increasing trend in recent32years. Its climatic trend rate is0.67℃/10a,and its mutation occurred in1998.the wavelet analysis indicates that the mean temperature has a certain periodicity in the14year time scale.The mean annual precipitation is1701.4mm,in the recent32years with a slight decreasing trend. Its climatic trend rate is-4.5mm/10a,which did not pass the significance test. The mean annual of sunshine hours,the mean relative humidity and the mean evaporation were2014.5h,77%and1609.5mm respectively.(2)The early rice mean yield of the experimental field in the agricultural meteorology station of Chaozhou is863.9g·m-2in the recent30years,the early rice yield of the experimental field has a significant decreasing trend in recent30years.Its trend rate is58.9g·m-2/10a which passed the significance test.By the analysis of the yield factors,the shell rate of early rice was significantly negatively correlated with early rice yield,the correlation of other factors were not significant.The analysis indicated that the strength of the variety of climatic factors on early rice yield is different.In order to predict the future trend of early rice yield,a multivariate regression model was set up which has a good imitation effect,the model indicates that the most contribution on early rice yield is the precipitation in June and July,followed by the precipitation in April and May.The multiple correlation coefficient R=0.644, which passed through the a=0.001correlation test.(3)The climate changes in future are estimated by using the results of climate model.Among them, the temperature will increase obviously.Meanwhile,the trend of precipitation will increase. So,it will be significant warming and wetting in Chaozhou in21st century which is slightly different from the climate change trend of the nearly32a.But the change trend isn’t the same in different situation of climate change,compared with SRES of A1B and Bl,under the high emission SRES A2,which has the most significant climate changes,the temperatures will increase by2.4℃.(4)The early rice yield was calculated by the trend of precipitation and temperature in the21st century.In the situation of SRES A2,the early rice yield’s decline trend was the most significant,which will reduce by181g·m-2;however,in the situation of SRES A1B and B1,the early rice yield will reduce by156.6·m-2and109.4g·m-2respectively.The decreasing trends have passed the significance test.The increasing future temperature will short the early rice growing period which will make the early rice yield down in the future. The weak decreasing trend of precipitation will cause the decline of the early rice yield in a certain extent.It indicates that reducing the emissions of greenhouse gas such as carbon dioxide has positive effect to slow the reduction of early rice yield in Chaozhou.