2008年长江流域油菜低温冻害调查分析

Investigation on 2008'low temperature and freeze injure on winter rape along Yangtze River

2008年1月,我国遭受了严重冰雪低温灾害,对冬油菜生产造成了严重的影响。对全国受灾地区油菜种植户进行的随机抽样调查表明,受灾面积约占全国冬油菜面积77.8%,主要包括湖北、湖南、江西、安徽、江苏、浙江、上海、贵州、云南、广西等省。在受灾区随机抽样调查10050株油菜中,未发生冻害的油菜占22%,1、2级的轻度和中等冻害分别占34.4%和30.7%,3、4级的严重冻害和致死冻害分别占11.9%和1%,平均冻害指数为33.9。冻害最严重的地区主要分布于北纬27°左右的长江流域范围内,包括湖南西部和南部、广西北部、江西南部、浙江南部、贵州、云南北部等。根据灾后考察,主产区绝大部分油菜恢复较好,预计冻害影响将造成全国冬油菜产区单产比去年减产10.9%。但由于冬油菜播种总面积增加17%,四川、重庆、黄淮等未受冻害,总产仍可比去年增加4.3%左右。根据2008年油菜冻害防治的经验和教训,今后应大力选育和推广抗寒耐冻的新品种,并加强油菜田间种植管理;通过适期播种、合理施肥、中耕培土、摘薹等生产措施提早预防。

South China was exposed to an extreme weather of low temperature, ice rain and heavy snow in January 2008. This unusual ice-frozen weather caused serious damage to winter rape. Investigating by random sampling rape grower indicated that affected area accounts for 77.8% of the overall winter rape area in the country, including areas in Hubei, Hunan, Jiangxi, Anhui, Guizhou, Yunan, Jiangsu, Zhejiang, Shanghai. Total sample number was 10 050 in dividual rape plant, in which 22.0% of plant showed no injury, and ones had gentle and moderate injury accounts for 34.4% and 30.7% respectively, with 1 and 2 grades freeze injury indexes. About 11.9% plant suffered a severe injury with 3 grades freeze injury index and 1.0% suffered lethal frozen injury with 4 grade freeze injury index. The mean freeze injury index was 33.9 of all areas in China. The most seriously damaged area was along Yangtze River, which at about 27 degree north latitude, and covered West and South of Hunan, North of Guangxi,South of Jiangxi, South of Zhejiang, most of Guizhou and North of Yunnan areas. Our results showed that most damaged plant recovered well from freeze injury in two weeks when snow started melting. The yield per hectare would be expected to reduce 10.9% compared to last year＇ all over China due to the ice-snow disaster. But due to the total planting area of winter rape increased 17.0%, and together with unaffected areas in Sichuan, Chongqin, Yellow and Huaihe River areas, total yield could increase 4.3% compare to last year. Measurements should be used to prevent freeze injury after this experience of extreme low temperature,we may be better prepared for such condition in the future if we can adapt our breeding program, popularize freeze resistance varieties, enhance variety management, sow late in the season rationalize the managemont such as fertilizing,inter-tilling cutting old leaf and injured peduncle.