The winter wheat late frost disaster（WFD） occurs mainly in the Yellow and Huaihe River area,of which Henan Province covers the most part.Henan is the major area of wheat production in China,but it is severely hit by...The winter wheat late frost disaster（WFD） occurs mainly in the Yellow and Huaihe River area,of which Henan Province covers the most part.Henan is the major area of wheat production in China,but it is severely hit by the WFD.In this study,we construct a WFD index based on the minimum temperature and the winter wheat development period（WDP）.The WFD degrees and days at 30 agrometeorological stations in Henan Province during the period of 1981-2004 are calculated.For the large-scale temporal variation analysis of WFD,the 24-yr WDP observation series is relatively short,so it is expanded by using the relation between the turning green date of winter wheat and the 5-day running mean temperature and that between the stem elongation phase and the effective cumulative temperature above a critical value of 2.5 ℃.The WFD data are also expanded for the last 50 years and are analyzed by using the empirical orthogonal function（EOF） and the Morlet wavelet methods.Characteristics in the spatial distribution and temporal variation of WFD are revealed.The results show that the frequency of WFD is generally high,exceeding 40% in parts of Henan,and exhibits a rising trend in the period of 1970-1990.The variation trend of WFD degrees is similar to that of WFD days,and the areas with higher WFD degrees coincide the areas with more WFD days.Moreover,the WFD degree has a greater impact on the winter wheat yield than the WFD days.The areas with high WFD degrees lie in the southeast and southwest of Henan,and the areas with low WFD degrees lie in the south of the Huaihe River and parts of western Henan.Temporal variations of the first and second EOF modes of the WFD degree display 16-and quasi-22-yr periodicities,respectively.The areas of high（low） WFD frequency are distributed in the northern Henan and the southwest border of Henan（the northeast Henan and the middle part of southwest Henan）.The temporal variation of the first（second） EOF mode of WFD days exhibits a periodicity（periodicities） of quasi-4 yr（quasi-3 and quasi-6-7 yr）.展开更多
A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well document...A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well documented, but information is lacking for sweet sorghum. Three and six commercial cultivars of sugarcane and sweet sorghum, respectively, were selected and evaluated for exposure to a late fall frost (-2.8°C) in Griffin, Georgia, USA. Under the same controlled environmental conditions in a screen house, the late fall frost induced more damage to sugarcane than sweet sorghum stems. The frost caused damage to sugarcane tissue and for juice to exude from stems, whereas similar behavior was not observed for sweet sorghum. In both sugarcane and sweet sorghum, the glucose/fructose ratio was significantly reduced, but this change may not be totally directly related to the frost effect. Overall, these initial results suggest that sweet sorghum may have a better tolerance to fall frost than sugarcane. Two sweet sorghum cultivars, Grassl and M81E, responded well to the late fall frost, and they can possibly be used as feedstocks for biofuel/bioproduct manufacture in areas susceptible to frosts including northern regions of the Southeastern US.展开更多
基金Supported by the Key National Sci. & Tech. Pillar Program during the 11th Five-Year Plan Period (2006BAD04B00)National Natural Science Foundation of China (30771248)New Technical Promotion Project of the China Meteorological Administration(CMATG2006M39)
文摘The winter wheat late frost disaster（WFD） occurs mainly in the Yellow and Huaihe River area,of which Henan Province covers the most part.Henan is the major area of wheat production in China,but it is severely hit by the WFD.In this study,we construct a WFD index based on the minimum temperature and the winter wheat development period（WDP）.The WFD degrees and days at 30 agrometeorological stations in Henan Province during the period of 1981-2004 are calculated.For the large-scale temporal variation analysis of WFD,the 24-yr WDP observation series is relatively short,so it is expanded by using the relation between the turning green date of winter wheat and the 5-day running mean temperature and that between the stem elongation phase and the effective cumulative temperature above a critical value of 2.5 ℃.The WFD data are also expanded for the last 50 years and are analyzed by using the empirical orthogonal function（EOF） and the Morlet wavelet methods.Characteristics in the spatial distribution and temporal variation of WFD are revealed.The results show that the frequency of WFD is generally high,exceeding 40% in parts of Henan,and exhibits a rising trend in the period of 1970-1990.The variation trend of WFD degrees is similar to that of WFD days,and the areas with higher WFD degrees coincide the areas with more WFD days.Moreover,the WFD degree has a greater impact on the winter wheat yield than the WFD days.The areas with high WFD degrees lie in the southeast and southwest of Henan,and the areas with low WFD degrees lie in the south of the Huaihe River and parts of western Henan.Temporal variations of the first and second EOF modes of the WFD degree display 16-and quasi-22-yr periodicities,respectively.The areas of high（low） WFD frequency are distributed in the northern Henan and the southwest border of Henan（the northeast Henan and the middle part of southwest Henan）.The temporal variation of the first（second） EOF mode of WFD days exhibits a periodicity（periodicities） of quasi-4 yr（quasi-3 and quasi-6-7 yr）.
文摘A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well documented, but information is lacking for sweet sorghum. Three and six commercial cultivars of sugarcane and sweet sorghum, respectively, were selected and evaluated for exposure to a late fall frost (-2.8°C) in Griffin, Georgia, USA. Under the same controlled environmental conditions in a screen house, the late fall frost induced more damage to sugarcane than sweet sorghum stems. The frost caused damage to sugarcane tissue and for juice to exude from stems, whereas similar behavior was not observed for sweet sorghum. In both sugarcane and sweet sorghum, the glucose/fructose ratio was significantly reduced, but this change may not be totally directly related to the frost effect. Overall, these initial results suggest that sweet sorghum may have a better tolerance to fall frost than sugarcane. Two sweet sorghum cultivars, Grassl and M81E, responded well to the late fall frost, and they can possibly be used as feedstocks for biofuel/bioproduct manufacture in areas susceptible to frosts including northern regions of the Southeastern US.
