再生稻再生芽萌发期降水量和作物需水量的年际变化特征分析

Annual variation of rainfall and crop water requirements of ratoon rice during the sprouting of axillary bud period

基于遂宁、内江、泸州、宜宾、纳溪和叙永等6个气象站1951—2007年的逐日气象资料,采用FAO推荐的Penman-Monteith公式计算再生稻作物需水量,并结合同期降水量,以自然降水量/作物需水量（R/ETc）为指标,探讨了川东南地区中稻再生芽萌发期（即7月下旬—8月中旬）的降水量和作物需水量的地区差异特征和年际变化特征。结果表明,遂宁、内江、泸州、纳溪、宜宾和叙永再生芽萌发期多年平均降水量分别为156.7、175.4、168.5、66.7、227.5 mm和153.4 mm。需水量多年平均分别为141.5、138.6、144.5、146.0、128.5 mm和142.7 mm。除了纳溪外,其余各地区再生芽萌发期的降水量均高于其作物需水量。从自然降水量和作物需水量之间的关系上看,宜宾、内江、泸州及叙永均较适合再生稻发展,而纳溪则存在较大的风险。进一步分析内江、泸州再生芽萌发期作物需水量和自然降水量的年际变化特征,发现从1951—2007年,内江降水量与需水量的比值〉1的年份占了63%,比值在0.85~1之间的概率为3%,比值在0.5~0.7之间的概率为11%,降水量与需水量的比值〈0.5为12%。从1951—2002年,泸州降水量与需水量的比值〉1的年份占了52%,比值在0.85~1之间的概率为13%,比值在0.5~0.7之间的概率为21%,降水量与需水量的比值〈0.5的概率为4%。相对而言,内江中稻再生芽萌发期仍然存在较大的受旱风险。根据以上结果,探讨了川东南再生稻发展适宜区及高产栽培策略,纳溪受旱风险较大不宜晒田,遂宁、宜宾、内江、泸州、叙永均能进行中期晒田。

Based on the daily data at six meteorological stations including Suining,Neijiang,Luzhou,Yibin,Naxi and Xuyong during 1951—2007,the FAO Penman- Monteith formula and the method of crop coefficient calculation were used to estimate the water requirements for ratoon rice during the period of sprouting of axillary bud（ from late July to mid-August） and the regional disparity and temporal distribution characteristics of precipitation and crop water requirement during this period were also explored. The results showed that the mean annual precipitation during sprouting of axillary bud were 156. 7,175. 4,168. 5,66. 7,227. 5 mm and 153. 4 mm,and annual crop water requirement were 141. 5,138. 6,144. 5,146. 0,128. 5 mm and 142. 7 mm for Suining,Neijiang,Luzhou,Yibin,Naxi and Xuyong,respectively. In consideration the relationship between rainfall and the crop water requirement,Yibin,Neijiang,Luzhou and Xuyong are suitable for ratoon rice,while Naxi is not. Temporal distribution of precipitation and crop water requirement during the period of sprouting of axillary bud was evaluated by calculating the ratio of rainfall（ R） to ETc. For Neijiang,63% of the years from 1951 to 2007 had a R / ETcratio above 1. 0,and 12% were below 0. 5. For Luzhou,52% of the years were above 1. 0,whereas 4% were below 0.5. In conclusion,Neijiang is vulnerable to drought stress during the sprouting of axillary period. The ecological regionalization of ratoon rice in southeast Sichuan is interpreted as a result. Yibin,Neijiang,Luzhou and Xuyong can dry paddy field at full heading stage,while Naxi cannot.