Evaluation And Application Of Climate Suitability Of Spring Maize In Northeast China

With the increasingly severe of climate environment,the influence of climate fluctuations on the growth of spring maize in Northeast China is gradually increasing.The 14 th Five-Year Plan emphasizes the importance of rational and full utilization of climate resources for the layout of agricultural planting structures.Climate suitability has become an important measure to comprehensively reflect the suitability of temperature,insolation,precipitation and other climatic factors during the growth period of spring maize.The traditional climate suitability model is basically based on actual precipitation,and the results are seriously affected by moisture consumption of non-crop such as evaporation of crop and soil surface,surface runoff,and deep seepage of soil.So that the estimated precipitation suitability is inconsistent with the actual precipitation of spring maize growth and utilization.Therefore,how to objectively and accurately express the suitability of precipitation during the growth of spring maize and improve the applicability of the climate suitability model is an urgent problem to be solved.In view of this,this paper took the Northeast China rich in maize as the research area,by using the meteorological data of 83 meteorological stations from 1961 to 2019,the phenological data of 34 agrometeorological stations from 1993 to 2013,and other multi-source auxiliary data to analyze the temporal and spatial variation characteristics of the dominant agroclimatic resources in the spring maize growing season in Northeast China.We proposed to introduce effective precipitation into the climate suitability model to reduce the influence of moisture except evevaporation of spring maize and improve the accuracy of the model.Then the climate suitability of spring maize in Northeast China was evaluated and regionalized to provide effective information for spring maize in Northeast China to cope with climate risks,optimize maize planting areas,and strengthen agricultural production management.The main conclusions were as follows:(1)The average temperature of spring maize growing season in Northeast China increased from the southwest to the northeast,the insolation decreased from the southeast to the northwest,and the precipitation decreased insignificantly and changed periodically.In view of the fact that high temperature,little insolation and precipitation had a great influence on the healthy growth of spring maize,this paper established temperature,insolation and precipitation suitability models based on the temperature,insolation,water demand indices and existing achievements for suitable growth of spring maize in Northeast China,and determined the parameter values and corresponding weights of different climatic elements in the growth period.Then the effective precipitation and actual precipitation were coupled with temperature and insolation to establish the synthetic climate suitability model I and model II,respectively,which provided a model reference for reflecting the climatic suitability of spring maize in Northeast China.(2)To test the applicability of the model,we adopt the remote sensing vegetation index and climate yield to validate the model effects of remote sensing and ground angle of the climate suitability model I based on effective precipitation and the climate suitability model II based on actual precipitation through the Hailun and Tailai typical agricultural stations in Northeast China.The results showed that the correlation coefficients(0.74,0.71 and 0.08,0.22,0.13 and 0.54)of the synthetic climate suitability of the whole growth period estimated by the model I and Normalized Difference Vegetation Index(NDVI),Enhanced Vegetation Index(EVI)and climate yield were better than the model II(0.43,0.68 and 0.01,0.18,0.01 and 0.41)in Hailun and Tailai stations.The model I of integrating effective precipitation can more effectively capture the stress phenomenon of climatic factors on spring maize growth.(3)The climate suitability model I was applied to estimate the suitability of various climatic elements in different growth periods at 83 stations from 1961 to 2019 in the typical maize planting areas of Northeast China,and used the coefficient of variation and fluctuation to evaluate the application effect.The results showed that the climate suitability of spring maize in Northeast China was temperature > insolation > effective precipitation.Temperature could basically meet the growth demand of spring maize in Northeast China,and effective precipitation was the key factor limiting the growth of spring maize.Temperature suitability increased significantly during the whole growth period,while insolation,effective precipitation and synthetic climate suitability decreased.Temperature suitability of the southwest was greater than the northeast,and insolation suitability of the northwest was greater than the southeast.While the spatial distribution of effective precipitation and synthetic climate suitability was roughly opposite to that of insolation suitability.Besides,the suitability of insolation and effective precipitation had a stable and full-time cycle of about 4～17 years and 17～30 years.And temperature,insolation,effective precipitation and synthetic climate suitability were higher in sowing to milking,milking to maturity,three-leaf to tasseling and three-leaf to jointing,respectively.The suitability of different climatic elements in each growth period had a cycle of about 2～5 years with poor time domain.In addition,the coefficient of variation and fluctuation of temperature suitability were the lowest,the suitability of effective precipitation was the highest,and the variation coefficient(16.09%)and the fluctuation coefficient(12.92%)of synthetic climate suitability were the largest in emergence to three-leaf,which echoed the results of the applied analysis of model I.(4)The synthetic climate suitable regions for spring maize were mainly located in Liaoning Province,the central region of Jilin Province and the central southern region of Heilongjiang Province.These regions have a good mix of temperature,insolation and precipitation resources for spring maize.In other areas,the spring maize growth management mode needs to be adjusted according to the corresponding climatic stress in time.In conclusion,the climate suitability model Ⅰ based on effective precipitation constructed in this paper shows potential advantages in capturing the growth situation of spring maize,which can provide a new idea for the evaluation of climate suitability.The paper has 37 figures,6 tables and 88 references.