Spatiotemporal Characteristics Of Maize Low Temperature And Cold Damage And Its Effect On Maize Yield In Heilongjiang Province

Aiming at the problems related to maize low temperature and cold damage in Heilongjiang Province,by using the temperature date from May to September of 15 agro-metrorological stations and the date of maize field during 1960-2009 in Heilongjiang province,the paper discriminates and classifies low temperature and cold damage on the basis of the low temperature and cold damage index ?T5-9 under different accumulated temperature.Adopting trend analysis,coefficient of variation,ArcGIS spatial interpolation analysis,the temporal and spatial distribution of maize general and serious low temperature and cold damage in Heilongjiang Province is conclued.The article analyses the effect of low temperature and cold damage on maize yield in Heilongjiang province by using correlation analysis method by SPSS and Mann-Kendall test of sudden change.The statistical results show that:(1)Maize low temperature and cold damage occurred during 1960-2009 in Heilongjiang Province over time showed a decreasing trend,in 60s and 70s of last century the temperature is low,and the fluctuation is not stable,the frequent occurrence of low temperature and cold damage,effects on crops greatly.In 80s there are still temperature fluctuations but the fluctuation range is significantly smaller,there are several severe cold damage times during the years,but the overall frequency decreased.Since 90s,the frequency and degree of occurrence of maize low temperature and cold damage decreased gradually and lightened the trend.The first 10 years of the twenty-first Century Boli county only had a general low temperature and cold damage.(2)The change of heat resource of corn planting area in Heilongjiang province is not stable,the greatest risk of low temperature and cold damage in 70s of the last century.The risk of low temperature and cold damage in eastern region is significantly higher than the western region,the northern region is slightly higher than the southern region in space.In twenty-first Century the temperature fluctuations often occur,the risk of low temperature and cold damage still exists,although the global warming,but the defense work of low temperature and cold damage is still indispensable.(3)In the 50 years of 1960-2009,occurrence frequency of general and severe low temperature and cold damage in different areas and years decreased.The degree of general low temperature and cold damage in first 40 years of the years is much more serious than last 10 years,and the degree of severe low temperature and cold damage in first 30 years is more serious than last 20 years time-wise.In 1960s,the highest frequency of occurrence of genera low temperature and cold damage,affected a wide range of damage,the greatest harm,70s slowed.While the severe low temperature and cold damage in1960s and 1970s were high frequency.The frequency of general low temperature and cold damage in the eastern region is the highest,the southern and northern regions of low frequency in spcace.The severe low temperature and cold damage occurred several times in the four directions.The eastern region and the southwest region of severe low temperature and cold damage have in low frequency.In particular,in the 50 years,the city of Wuchang has never occured general low temperature and cold damage,but frequent occurrence of severe low temperature and cold damage,and frequency fluctuation.Cold damage has characteristics of regional and clustered.The individual area showed an increasing trend in low temperature and different years.(4)There was a significant correlation between the average temperature of maize growth period and the actual yield of maize from 73%agro-metrorological stations.The results showed that the fluctuation of temperature had a certain effect on maize yield.The maize yield decreased significantly in the years of sudden change,which indicated that low temperature could lead to the reduction of maize yield.(5)We should cope with activily maize low temperature and cold damage in Heilongjiang Province,by chosing good adaptability cold resistant varieties,achieving the combination of prevention and monitor,early forcast,doing insulation work,combined with the regional disaster situation,adjusting the agricultural structure and improve the crop varieties layout,improving corn resistance to low temperature technology,scientific irrigation and fertilization,artificial pollination when necessary to reduce the effect of low temperature on maize yield.