Abstract: In this study, the average daily temperatures from September to November in Nantong City were analyzed. According to the critical temperature indices for japonica rice, obtained rice safe dates of full heading and maturity and the guarantee rate for the safe dates was 50%, 80%, and 90%, respectively. It was observed that the safe dates of full heading during the third 20 years were eight to nine days later than those during the first and second 20 years, and the safe dates of maturity were five to ten days later, respectively. It was observed that as the globe warmed, the critical temperature indices of full heading （20℃） would not develop the function of guiding production, and proposed the reference index, the summation of effective temperature from full heading to maturity, to predict the dates through the security maturity forward daily cumulative effective temperature （≥10℃）. The corrected safe dates for full heading of 80% were September 6, 25 days earlier than initial predicted dates.

Key words: Nantong City, japonica rice, safe dates of full heading, safe dates of maturity, average daily temperature, effective temperature

摘要： 以江苏省南通市1951-2010年9月至11月份日平均温度为资料，根据有关界限温度指标，推测保证率为50%、80%和90%的粳稻安全齐穗期和安全成熟期。结果发现，1991-2010年这20年水稻安全齐穗期和安全成熟期较之前的两个20年均有不同程度延迟，80%保证率的安全齐穗期分别推迟8 d、9 d，80%保证率的安全成熟期分别推迟10 d、5 d；同时发现，在气候变暖形势下以20℃作为安全齐穗的指标已经难以发挥指导生产实际的作用，进而提出以齐穗至成熟期有效积温为参考指标，通过安全成熟期向前累加活动积温（≥10℃）的方法来修正安全齐穗期。修正后的安全齐穗期较原推测日期提早25 d左右，即80%保证率安全齐穗期在9月6日左右。

关键词: 南通市, 水稻, 安全齐穗期, 安全成熟期, 日平均气温, 有效积温