Impact Of Climate Change On Climate Suitability For Tea Planting In Jiangsu Provinc

Climate is an essential factor in crop growth,yield and quality,and the impact of climate change on crop climatic suitability has received much attention.Tea,one of Jiangsu’s major agricultural products,plays an essential role in the hilly agricultural production of Jiangsu province.Based on the daily meteorological data in the past 50 years(1965-2014)from 13 meteorological stations in the province,the growing periods of tea in the province was subdivided into three growing period(spring,summer and autumn).The interannual variation and spatial distribution of climate resources in different growing periods were analyzed using the method of climate propensity estimation,M-K detection,and wavelet analysis.Combined with previous research results and actual tea growth situation in Jiangsu,the suitability model of temperature,moisture and sunshine of Jiangsu tea was established to evaluate the interannual changes and spatial distribution of climatic suitability of tea in the past(1965-2014)and the future(RCP4.5 2015-2049),in order to provide reference for the safe production of tea in the province.The main conclusions are listed as follows:(1)Temporal and spatial variations of climate resources in different growing periods of Jiangsu tea in the last 50 yearsIn general,the climate has become warmer and wetter over the past 50 years in the province,from 1965 to 2014.Temperature and precipitation are higher in southern Jiangsu than in northern Jiangsu,and the duration of sunshine in northern Jiangsu is higher than in southern Jiangsu.The interannual and spatial variations in effective accumulated temperature,precipitation,humidity,and sunlight are different for different growth periods.The temperature and effective accumulated temperature of Jiangsu tea during the three growing periods show a significant increase trend,with the fastest rising rate being 0.43℃/10 a and 30.6℃?d/10 a,respectively.Apart from summer tea,the precipitation in the growing period of spring tea and autumn tea indicates a downward trend.Humidity shows a decrease trend in each growing period,and the fastest decreasing rate was at-1.7%/10 a in the growing period of spring tea.Apart from spring tea,the sunshine duration of summer tea and autumn tea show a decreasing trend.The overall heat resources of tea in the province in different growing periods are higher in the south and lower in the north of Jiangsu.The average temperature of tea in the north,the middle and the south was about 20℃,20.5℃ and 20.7℃,respectively.Overall precipitation resources are higher in the south and lower in the north.The average precipitation in the north,the middle and the south is about 830 mm,870mm and 900 mm,respectively.Total sunshine duration is higher in the north and lower in the south.The average duration of sunshine is around1580 h in the north,1500 h in the middle and 1400 h in the south,respectively.The mismatch of different meteorological factors in different growing periods may limit the growth of tea in the area.(2)Temporal and spatial variations of tea climatic suitability in the last 50 years in Jiangsu provinceOver the past 50 years,from 1965 to 2014,the temperature and sunshine suitability of Jiangsu tea have been increasing during the overall growing periods,with trend rates being0.015/10 a and 0.006/10 a,respectively.The variation of precipitation suitability shows a significant decreasing trend,with the trend rate being at-0.028/10 a.The comprehensive suitability shows a decreasing trend,with the trend rate being at-0.005/10 a.The temperature fitness gradually increases with time across the province,and the region of high temperature fitness expands from the south to the north.The precipitation suitability gradually decreases with time,with high-value suitability decreasing from north to south.The province as a whole has seen a gradual increase in sunshine availability over time,with high-value areas showing an expanding trend from north to south.The overall climatic fitness in the province gradually decreased over time,with high-value areas of integrated fitness declining from north to south.At present,the most suitable area for tea cultivation is still located in southern Jiangsu.(3)Temporal and spatial changes of climatic suitability of Jiangsu tea under future climate change scenariosAccording to the tea climatic suitability under the future climate change scenario model,compared with the past 30 years,the temperature and precipitation in the whole province will continue to increase,the temperature suitability under the existing tea area will continue to increase,the precipitation suitability will show a downward trend,and the comprehensive suitability will basically remain unchanged,but the comprehensive climatic suitability will decrease in Jurong tea area,Zhenjiang.The area of climate suitable for cultivation shrinks gradually from north to south.In the RCP4.5 climate scenario,The decline of tea climatic suitability in Ningzhen Yang Tea District deserves attention,and the climatic suitability of potential hilly tea growing areas will be further reduced.The results of this study are helpful in further elucidating the climate resources and tea production safety in the context of global climate change in Jiangsu province.