江淮地区玉米涝渍指标构建及时空特征分析

THE CONSTRUCTION METHOD AND ITS SPATIO TEMPORAL CHARACTERISTICS OF MAIZE WATER LOGGING RANKS INDEX IN JIANGHUAI REGION

关键词:  作物水分盈余指数底墒生育阶段涝渍敏感性玉米综合水分盈余指数

Key words:  CWSI  soil moisture in sowing  growth stage  waterlogging sensitivity  CWSIM

摘要:

［目的］江淮地区玉米涝渍灾害严重，研究揭示区域玉米涝渍灾害时空发生规律对科学开展区域防洪减灾具有重要意义。［方法］利用1981—2010年江淮地区18个站点地面气象观测数据和农业气象资料，基于作物水分盈余指数（CWSI），引入播种前底墒，根据玉米各生育阶段涝渍敏感性差异，采用层次分析法确定阶段涝渍灾害影响权重，构建适用于江淮地区玉米涝渍等级评估的玉米综合水分盈余指数（CWSIM），并根据典型涝渍年综合指数同对应减产率的线性回归方程，划分春、夏玉米不同等级涝渍的指标阈值。［结果］(1）春玉米的轻、中、重涝指标阈值依次为： 080≤CWSIM＜101,101≤CWSIM＜123,CWSIM≥123； 夏玉米为： 109≤CWSIM＜144,144≤CWSIM＜179,CWSIM≥179。(2）各阶段水分盈余指数（WSIM）分布规律，春玉米为：出苗—拔节期、拔节—吐丝期呈由北向南的纬向增加分布； 吐丝—成熟期高值区位于安徽省西南临江一带、江苏省淮安市东部、扬州市及其周边区域，低值区位于安徽省北部及中部的中心区域、江苏省东南边缘，其余为中值区。夏玉米为：出苗—拔节期呈由北向南的纬向增加分布； 拔节—吐丝期高值区位于江苏省东北部，低值区位于安徽省中部及临江一带，其余为中值区； 吐丝—成熟期指数呈由西向东的经向增加分布。(3）江淮地区近30年，春玉米CWSIM值由北向南呈纬向增加分布。整体指数在不同时期的排序为1991—2000年＞1981—1990年＞2001—2010年； 夏玉米CWSIM值由北向南呈近辐射状条带增加分布，不同时期指数排序为1991—2000年＞2001—2010年＞1981—1990年。［结论］安徽省沿江一带是玉米涝渍害发生的重灾区，且1991—2000年较其前后10年涝情最重。

Abstract:

Maize in Jianghuai region always suffers from waterlogging disaster, so it is of great significance to study and reveal the spatio temporal characteristics of maize waterlogging disaster to defense and reduce the disaster scientifically. Using ground observation data and agrometeorological data from eighteen meteorological stations in Jianghuai region from 1981 to 2010, we constructed the comprehensive water surplus index of maize (CWSIM) to evaluate maize waterlogging disaster in Jianghuai region by bringing in soil moisture before sowing and distributing weighting coefficients, which were calculated by analytic hierarchy process, to crop water surplus index(CWSI)in different growth stages of maize. And we divided CWSIM thresholds of spring maize and summer maize by calculating the regression equation between CWSIM with yield reduction in typical waterlogging years. The results were showed as follows. (1)The thresholds of CWSIM to evaluate spring maize waterlogging ranks were:0.80≤CWSIM＜1.01(light), 1.01≤CWSIM＜1.23(moderate), CWSIM≥1.23(severe). And for summer maize, they are: 1.09≤CWSIM＜1.44(light), 1.44≤CWSIM＜1.79(moderate), CWSIM≥1.79(severe). (2) For spring maize, the distribution rules of WSIM in different growth stages were found as follows. From seedling to jointing and jointing to spinning stages, WSIM was a latitudinal increased distribution from north to south; From spinning to mature stage, high value areas of WSIM were in southwest Anhui province bordering the Yangtze river, and east of Huai′an city, Yangzhou city and its peripheral zone. Low value areas of WSIM were in the center of northern and central Anhui province, and southeast edge of Jiangsu province. The others areas were middle value areas. For summer maize, the rules were found as follows. From seedling to jointing stage, WSIM was a latitudinal increased distribution from north to south. From jointing to spinning stage, high value area of WSIM was in northeast Jiangsu province, low value areas were in central Anhui province and its border with the Yangtze river, and others were middle value areas. From spinning to mature stage, WSIM was a longitudinal increased distribution from west to east; (3)In recent thirty years, CWSIM of spring maize was a latitudinal increased distribution from north to south, and the order of mean CWSIM in every decade was: 1991-2000＞1981-1990＞2001-2010; For summer maize, the high value area of CWSIM was main in Anhui province bordering the Yangtze river, the low value area was in east of north Anhui province, and others were middle value areas. The order of mean CWSIM in every decade was:1991 2000＞2001-2010＞1981-1990. In general, the main waterlogging disaster area of maize in Jianghui region is Anhui province bordering the Yangtze river, and waterlogging disaster of maize from 1991 to 2000 is heavier than other decades.