川中丘陵区不同播期玉米生育期气候资源及干旱特征分析以中江为例

Climatic resources and drought characteristics of maize sown in different dates in the hilly area of central Sichuan: A case study of Zhongjiang, Sichuan

  • 摘要: 川中丘陵区是西南玉米主产区之一, 季节性干旱是该区最主要的农业气象灾害, 研究不同播种时期玉米不同生育阶段气候资源及干旱特征对该区玉米避旱减灾有重大意义。本文以川中丘陵地区的中江为例, 利用1981—2020年四川省中江县气象站地面气象观测资料, 从3月下旬至6月上旬设置8个播期, 分析不同播期玉米生育期主要农业气候资源变化规律, 同时基于作物水分亏缺指数(CWDI)研究不同播期玉米各生育阶段干旱特征, 为川中丘陵区玉米适宜播期选择和生育期内阶段性干旱防御提供科学依据。结果表明: 1)近40年各播期玉米生育期气候资源变化均呈日照时数下降、温度升高、降雨量下降的趋势; 随播期推迟, 日均温、生长度日、高温度日均先升后降, 日照时数随播期推迟呈下降趋势, 而降雨量则随播期推迟呈增加趋势。适当推迟播期, 有利于提高玉米对日照、热量和降水资源的综合利用。2)随播期推迟, 玉米播种—拔节、拔节—抽雄阶段CWDI呈明显降低趋势, 3月下旬播种玉米抽雄—灌浆阶段CWDI明显高于其他播期; 推迟播期可降低玉米生育期水分亏缺的危险。3)不同播期玉米最易受旱生育阶段存在差异, 3月下旬、5月下旬、6月上旬播种玉米在播种—拔节阶段干旱频率最高, 4月上旬—5月中旬播种玉米在拔节—抽雄阶段干旱频率最高。4)各播期玉米各生育阶段干旱强度以轻旱、中旱为主, 重旱次之, 特旱最低; 推迟播期玉米干旱强度由中旱降为轻旱为主, 可降低玉米干旱发生频率, 特别是重旱和特旱发生频率。研究区玉米宜在5月中旬前播种; 玉米在3月下旬、4月上旬播种时, 应注重灌浆期以前的抗旱管理; 4月中旬到5月中旬播种时, 应注重抽雄前的抗旱管理, 同时预防灌浆—成熟阶段的高温风险。

     

    Abstract: The hilly area of central Sichuan is one of the main maize-producing areas in Southwest China, where seasonal drought is the main agro-meteorological disaster. It is of great significance to study the climatic resources and drought characteristics of maize at different growing periods with different sowing dates for maize drought avoidance and disaster reduction in this area. Using Zhongjiang County in the hilly area of central Sichuan as an example, based on the surface meteorological observation data of Zhongjiang Meteorological Station from 1981 to 2020, eight sowing dates with 20 days intervals were set from late March to early June to analyze the change laws of main agro-climate resources during maize growth periods under different sowing dates. At the same time, based on the crop water deficit index (CWDI), the drought characteristics of maize at different growth periods under different sowing dates were studied to provide a scientific basis for the selection of suitable sowing dates and the prevention of staged drought during the growth periods of maize in the hilly region of central Sichuan. The results showed that first, over the past 40 years, the changes in climatic resources during the maize growth season of each sowing date showed a trend of decreasing sunshine hours, increasing temperature, and decreasing rainfall. With the delay in sowing date, the daily average temperature, growing degree days, and heat degree days first increased and then decreased, while the sunshine hours gradually decreased and the rainfall gradually increased. Therefore, appropriately delaying the sowing date of maize is beneficial for improving the utilization of sunshine, heat, and rainfall resources. Second, with the delay in sowing date, the CWDI during the maize sowing–jointing and jointing–tasseling periods noticeably decreased, and the CWDI during the tasseling–filling of maize sown on the late-March was significantly higher than that on other sowing dates. Delaying the sowing date can reduce the risk of water deficits during the maize growth periods. Third, there were differences in most susceptible growing period to drought among different sowing dates. Maize sown in late March, late May, and early June had the highest drought frequencies during the sowing–jointing stage, and maize sown from early April to mid-May had the highest drought frequency during the jointing–tasseling stage. Fourth, the drought intensity at each growing period of maize sown in different dates was dominated by light and moderate drought, followed by severe drought, with extreme drought occurring the lowest. When the sowing date was delayed, the maize drought intensity decreased from moderate to mild. Appropriately delaying the sowing date of maize can reduce the frequency of drought, especially the frequency of severe and extreme drought. The proper sowing date of maize in the study area is before mid-May. When maize is sown in late March and early April, attention should be paid to drought resistance management prior to the grain-filling period. When sowing from mid-April to mid-May, attention should be paid to drought resistance management before tasseling to prevent high temperature risks during the filling-maturity stage.

     

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