Response Of Maize Growth And Development To Climate Change In Heilongjiang Province

As the most sensitive area of climate changing in China,it is of significant and practical value to study the influence of climate changes on maize growth in Heilongjiang provinc,which has theoretical and practical value in regional growing and grains safety.Inthis study,based on the daily meteorological data of 80 weather stations and corresponding maize yield date from the year 1961 to 2017 and maize growth and development data of 23 agricultural meteorological stations between 1980 and 2017,the effects of climate change on maize growth and development were analyzed by means of integral regression and wavelet analysis.The climatic mechanism of maze yield formation process was revealed,the evolution characteristics of the climatic potentialproductivity and the potential utilization efficiency of heat and precipitation were clarified,and the potential space for improving heat and precipitation utilization efficiency of maize production were determined.The main results are as follows:(1)Affected by climate change,the maizegrowing seasonin the study areashowed a very significant extension trend from 1980 to 2017,with a rate of 2.5d/10a.The vegetative growth period of maize showed a shortening trend with a rate of 0.6d/10a,and its reproductive growth period showed a significant extension trend with a rate 2.0d/10a.The daysof vegetative growth,reproductive growth and whole growth in thestudy area are closely related to geographical factors and meteorological factors.The growing season of maize is shorter in the areas with high latitude andlow heat,which is characterized bylonger vegetative growth period and shorter reproductive growth period.Atthe same longitude and altitude,the latitude moved northward by 1°,the maize growing season,vegetative growth period and reproductive growth period were shortened by 2.3d,24.4d and 0.7d respectively.And the opposite is true in the areas with low latitude and high heat.(2)For the whole growing season of maize,the whole growth period of maize was divided into 10-days biological periods from early May to late September.504 groups of meteorological indicators,12 dynamic evaluation equations of zaizemeteorological yield and 36 expressions of the variability(sensitivity coefficient)of meteorological factors affecting maize meteorological yieldwere established in 4 districts.For example,during the criticalperiod from jointing to milk ripening in Area I,the effect of temperature was positive,whilethe effect of precipitation and sunshine was negative.Comparing with the suitable indicators,the temperature,precipitation and sunshine in this periodincreased(decreased)by1 meteorological unit,the maize meteorological yielddecreased(increased)by 104.3 kg·hm-2·?-1,1.kg·hm-2·mm-1.),0,3 kg·hm-2·h-1.The dynamic evaluationof the influence of meteorological conditions on maize yield was realized.(3)Under the background of climate warming,the maize climate potential productivity in the whole province from 1961 to 2017 increasedyear by year,and the rate is close to 40 kg·hm-2·a-1.In recent 37 years,the rate of increase was 29.]kg·hm-2·a-1 higher than thatin the previous 22 years.The climate potential productivity of maize is the lowest in the Great and SmallHinggan Mountains,mostly less than 1000kg·hm-2.While in Songnen Plain and Sanjiang.Plain,it's relatively high,the maximum is about 18000 kg·hm-2.The climate potential production of maize decreases from West to Eastwith the increase of latitude and altitude,and the descending rate is ranked as follows:latitude>longitude>altitude.(4)From 1961 to 2017,the potentiality of heat use efficiency of maize growth season in the whole province showed a weak decreasing trend.The annual average heat utilization efficiency potentialityof maize was 6.81 kg·hm-2·?-1,the maximum value was 7.65 kg·hm-2·?-1 and the minimum value is 5.87 kg·hm-2·?-1.The totalchange trend of maize precipitation utilization efficiency potentiality is "M" curve,showing two high and two low trends,the maximum value is 58.2 kg·hm-2·mm-1 andthe minimum value is 33.4 kg·hm-2·mm-1.Theprecipitation utilization efficiency of maize is lower in the north of Humain Great Hinggan Mountainsand alongNing'an and Dongning in Mudanjiang City.So,agricultural technology measures should be taken to improve the utilization rate of precipitation.And the heat utilization efficiency potentiality of maize that can be excavatedis less than 4.7 kg·hm-2·?-1 in the northern areas inthe Great and SmallHinggan Mountains and inthe southern areas in Mudanjiang.