Study On The Occurring Law Of Cool Summer Damage On Rice In Heilongjiang Province

The paper targeted against the coot summer damage which imperils the production of rice severelyin Heilongjiang province. Relational models between yield component factors and temperature indexeswere built up through the analysis of data including growth observation data of rice and daily meantemperature in 10 agro-meteorological observation stations from May to September in 6 years from1999 to 2004. And a computation and inquiry interface of cool summer damage on rice in Heilongjiangprovince was established with the grid data of daily mean temperature from 2000 to 2004 using VisualC++ and the GIS technology. Analysis in three aspects was made in this paper including the relationshipbetween the degree of the cool summer damage or the yield and meteorological elements in sensitivegrowth period, the spatial distribution characteristic of cool summer damage in Heilongjiang entireprovince and the change law of the impact on rice by the cool summer damage in different transplantingdate. Main results are as follows1. The degree of the cool summer damage or the yield was depended greatly on temperaturecondition around the heading time. The temperature condition from jointing stage to heading time, 10days after heading time and from heading time to ripeness stage has an impact on the yield eventuallythrough change the three yield component factors of stem weight, sterile rate and 1000 grains weight.2. There is a regional spatial distribution of cool summer damage on rice in Heilongjiang province.It is a zone where cool summer damage occurred frequently in the central area. Cool summer damageoccurred most frequently in the area spread from Heihe district in the north Heilongjiang provinceacross Wudalian Lake and Xiao Hinggan mountains to the Yichun district. There is another area wherecool summer damage occurred frequently in southward extension of the former area. This area spreadfrom Mudanjiang district to the most south area of Heilongjiang province, and the intensity andfrequency is weaker than the former area in the central & north area.In the latitudinal direction, the degree of cool summer damage of Sanjiang plain in the east is largerthan Songnen plain in the west. The cool summer damage occurred in Fuyuan district whereHeilongjiang province and Russia border on most frequently in the Sanjiang province. The degree ofcool summer damage shows the trend of gradually decreasing from Shuangyashan and Jiamusi districtto the Songnen plain. And the degree in west of Songnen plain is most slightly in the wholeHeilongjiang province, especially in Daqing and Qiqiha'er districts.3. The impact of cool summer damage on rice in Heilongjiang province varies from differenttransplanting date. The degree and frequency of cool summer damage increase along with thepostponing of transplanting date. The optimal transplanting date to avoid cool summer damage isbetween the 125 and 133 (day from January 1), namely from 5 May to 13 May. The probability and theintensity of cool summer damage can be greatly enhanced if transplant the rice in June, because thegrain filling period was greatly shorten. There is a rule of the degree of cool summer damage on rice in Heilongjiang province from 2000 to 2004 of 4 transplanting date showed as follow: transplant in 153(DFJ1)＞transplant in 143 (DFJ1)＞transplant in 133 (DFJ1)＞transplant in 125 (DFJ1). There nosignificant difference of the impact between transplanting in 125 and 133. However, the impact may belarger when transplanting in 123 than in 133. This kind of rule is especially obvious in years that suffera low temperature.