Variation Characteristics Of Heat And Precipitation In Suihua City Over The Past 60 Years And Effects On Grain Yield

Located in the central part of Heilongjiang Province,Suihua City is the largest green food production city in China.In 2020,the grain yield was 11.081 million tons,accounting for about 14%of the total in Heilongjiang Province.Heat and precipitation are closely related to crop growth,yield and quality,and are important meteorological factors for crop production,which seriously restrict the layout of agricultural production.Changes in heat and precipitation affect crop photosynthetic efficiency,dry matter synthesis,transport and storage,resulting in changes of crop growth processes,extreme weather can also cause crop physiological damage and mechanical damage,resulting in crop yield reduction.Global warming makes the distribution of heat and precipitation resources complex and changeable,which has an impact on the layout of agricultural production and brings a serious test to food security and agricultural sustainable development.At present,there is a lack of targeted research on the variation characteristics of heat and precipitation in Suihua City and its impact on grain production.Therefore,it is particularly important to explore the variation characteristics of heat and precipitation in Suihua City and its impact on grain production.In this study,four representative meteorological stations（Beilin,Hailun,Anda,Mingshui）in Suihua City were selected to collect the daily air temperature and precipitation data from 1955 to2020,The data of corn,soybean and rice sown area and yield from 1955 to 2020 in Suihua City,Beilin District,Hailun City,Anda City and Mingshui County were statistically analyzed.The linear tendency method and Mann-Kendall test method were used for descriptive analysis of the variation characteristics of heat and precipitation.ARIMA model was established to predict active accumulated temperature and frost-free periods in Beilin District,Hailun City,Anda City and Mingshui County in the next 10 years,descriptive analysis of sown area and yield variation characteristics of corn,soybean and rice in Suihua City,Pearson correlation analysis and linear fitting were used to analyze and linearly fit the correlation between active accumulation temperature,first frost day,last frost day,frost-free period,precipitation and yields of corn,soybean and rice.At the same time,the mild,moderate and severe cold damage at booting stage and flowering stage of rice in Suihua City in recent 66 years were statistically analyzed.The results showed that:（1）In the past 66 years,the last frost day in Suihua City showed an early trend,the first frost day showed a delayed trend,and the frost-free period showed an increasing trend,and the extension of the frost-free period mainly comes from the advance of the last frost day.Every 10 years,the last frost days of Beilin,Hailun,Anda and Mingshui were advanced by 3.2,2.3,2.6 and 3.2 days respectively,the first frost days were postponed by 1.3,0.1,0.3 and 1.0 days respectively,and the frost-free period were increased by 4.5,2.5,2.7 and 2.5 days,respectively.According to the prediction results of ARIMA model,the frost-free period of Beilin,Mingshui and Anda show an increasing trend in the next 10 years,and Hailun shows a decreasing trend.（2）In the past 66 years,the distribution of heat resources in Suihua City was southwest>southeast>northwest>northeast,and the active accumulation temperature show an upward trend.Every 10 years,the active accumulation temperature of Beilin,Hailun,Anda and Mingshui increased by 93.4,60.9,69.1 and 77.7°C·d,respectively,and the increase trend was southeast>northwest>southwest>northeast.According to the prediction results of ARIMA model,the average active accumulated temperature of Beilin,Hailun,Anda and Mingshui increased by 264.6,16.7,180.5 and142.8°C·d from 2011 to 2030 compared with the average active temperature of 2011-2020,respectively.（3）In the past 66 years,the distribution of annual precipitation resources in Suihua City was northeast>southeast>northwest>southwest,and the annual precipitation mainly comes from summer precipitation.The annual precipitation as a whole showed an increasing trend,and the annual precipitation of Beilin,Hailun,Anda and Mingshui increased by 12.8,4.4,10.5 and 13.3 mm respectively every 10 years,with an increase trend of northwest>southeast>southwest>northeast.（4）In the past 66 years,the yield of soybean,corn and rice in Suihua City showed an increasing trend,and the yield of soybean,corn and rice in Suihua City have increased by 195.0,1283.6 and1169.0 kg·hm^-2 respectively every 10 years,and the yield increase trend of corn>rice>soybean has been relatively stable in the past decade.（5）The active accumulation temperature and last frost days in Suihua City were significantly related to the per unit area yield of soybean,corn and rice.With the increase of active accumulated temperature and the advance of final frost date,the unit yield increased.Combined with the prediction results of ARIMA model,accumulated temperature in the next 10 years will promote the increase in grain yield in Suihua City.（6）In the past 66 years,the cold damage of rice obstacle type occurred frequently in Suihua City,and gradually decreased over time.In recent years,severe cold damage was sporadic.The frequency of chilling injury in the flowering stage was higher than that in the booting stage.Except Mingshui,the frequency of chilling injury in the booting stage was mild chilling injury>moderate chilling injury>severe chilling injury,the frequency of chilling injury in flowering stage was mild chilling injury>moderate chilling injury>severe chilling injury,the frequency of chilling injury showed a decreasing trend with geographical location from north to south.