| In accordance with the meteorological data of Zhongjiang County,Deyang in the past 58 years,as well as summarizes the changing law of agricultural climate resources and the climate features before sowing,within growth and after maturity of maize by relying on the changes of average temperature,maximum and minimum temperature,sunshine hours,rainfall and relative humidity respectively.Afterwards,the paper analyzes the law for the happening of extreme weather disasters in the local area based on the features of climate changes and climate resources within the growth period of maize.Moreover,the frequency of drought and its extent are also collected for statistics and calculating the influence function of precipitation and water content.The percentage of precipitation anomalies is also calculated to assess the drought situation.The Hybrid-Maize model is adopted to calculate the maize yield potential and simulate its yield potential for multiple years.Then,the reasons for the limitation of yield are found out by combining with features of climate and resources changes and the law for the happening of droughts.Finally,the the effective plan for resource utility is formulated to enhance the utility rate of resource.The main results are as follows:(1)Since 1960,the average temperature in the research area has been rising in a fluctuating way.Moreover,the major reason for the rising of annual average temperature is the temperature rising in winter and the changes of temperature in February are the most obvious with trend coefficient becoming high.2?rises in the past 58 years.The changing trend of the maximum and minimum temperatures is in line with that of the average temperature with temperature rising in spring and summer as the major one.Furthermore,the rising extent of minimum temperature is higher than that of the average temperature and the maximum temperature.Due to the obvious decreasing of total solar radiation and precipitation in summer and autumn,the relevant light resources,relative humidity and rainfall are in a downward trend in this regard.(2)It is found out after analyzing the climate resource features and the regularity for drought occurrence in maize growth period that the probability for the spring and summer maize facing drought in sowing and silking periods within the study area is higher relatively.The probability for the spring maize facing mid-drought and above in sowing period is 33.9%,28.8% in silking period.The probability for the summer maize facing drought in sowing period is 26.3%.Therefore,proper irrigation is required according to the drought situation and the special attention must be paid to water management for maize in the critical period of tasseling,while the precipitation is relatively larger for the harvest period of spring maize,so it is required to delay the harvesting process according to the growth of maize and climate conditions.(3)It is revealed by the analysis results of potential productivity of maize based on hybrid-model that the response of potential productivity of maize to temperature change is more obvious and what follows is precipitation and evapotranspiration for reference.Moreover,the factors directly affecting productivity include high temperature,drought and other extreme climate disasters.After the daily meteorological data in the past years is integrated and input into the H-M model to simulate the productivity potential of spring maize with different sowing times.It is revealed by the results that the simulated productivity of maize is in a downward trend with the delaying of sowing period and the best sowing period is the days before the mid-April.Among them,the productivity potential of maize sowed around March 25 is the highest.In terms of the productivity potential of summer maize,the maximum and minimum productivity fluctuates greatly in different years,but the average yield is kept in a relatively stable figure and maize sowed around May 18 shows the full productivity potential. |
PDF Full Text Request