鄂西烟区烤烟生育期降水量及灌溉需水时空变化特征分析

Spatial and Temporal Characteristics of Precipitation and Irrigation Water Requirement in Flue-cured Tobacco Growing Period in Western Hubei

为提高鄂西烟区水资源的合理分配和高效利用,选取湖北省西部烤烟种植区1975—2021年32个国家地面气象观测站逐日气象资料,计算烤烟各生育期有效降水量、需水量及灌溉需求指数,并对其时空变化进行研究。结果表明:近47年来,鄂西烟区烤烟伸根期平均有效降水量为52.0mm,呈递增趋势,旺长期、成熟期及大田期平均有效降水量分别为53.8mm、78.7mm、184.5mm,呈递减趋势,各烟区有效降水量总体表现为恩施烟区的>宜昌烟区的>十堰烟区的>襄阳烟区的;四个生育期平均需水量分别为55.2 mm、104.2mm、140.3mm、299.7mm,除旺长期变化趋势不明显,其余各生育期均呈递增趋势,各烟区需水量总体表现为襄阳烟区的>十堰烟区的>宜昌烟区的>恩施烟区的,旺长期变幅最大;四个生育期平均灌溉需求指数分别为0.06、0.47、0.42、0.38,均呈递增趋势,各烟区灌溉需求指数也呈缓慢递增,但变幅较小,总体表现为襄阳烟区的>十堰烟区的>宜昌烟区的>恩施烟区的,伸根期灌溉需求指数多在0值附近波动,其余各生育期的多处于0值以上。空间上,各生育期有效降水量呈南多北少分布,需水量分布则反之,灌溉需求指数北大南小,表明北部烟区对灌溉的依赖程度要远远高于南部烟区的。

To improve the rational distribution and efficient use of water resources in western Hubei Province,the daily meteorological data of 32 ground observation stations in the western flue-cured tobacco-planting region of Hubei Province from 1975 to 2021 are selected to calculate the effective precipitation,water requirement and irrigation requirement indexes of flue-cured tobacco in each growth period,and their spatio-temporal changes are studied as well.The results show that in the past 47 years,the annual average effective precipitation of flue-cured tobacco in the root extension period in western Hubei is 52.0 mm,showing an increasing trend.The average annual effective precipitation during the prosperous period,mature period and the field period are 53.8 mm,78.7 mm and 184.5 mm respectively,showing a decreasing trend.The overall effective precipitation in each tobacco area is manifested to be the Enshi precipitation>the Yichang precipitation>the Shiyan precipitation>the Xiangyang precipitation.The average annual water requirements in the four growth periods are 55.2 mm,104.2 mm,140.3 mm and 299.7 mm,respectively.Except that the water requirement in the prosperous period does not vary obviously with time,the water requirements in the other growth periods are all on the rise.The water requirement of each tobacco area is the most in Xiangyang,followed by that in Shiyan,Yichang and Enshi in order,with the largest variation in the prosperous period.The average irrigation requirement indexes are 0.06,0.47,0.42 and 0.38,respectively,showing an increasing trend with time.The irrigation requirement index in each tobacco area also shows a slowly increasing trend,but the variation amplitude is small.In general,the irrigation requirement of each tobacco area is the most in Xiangyang,followed by that in Shiyan,Yichang and Enshi successively.The irrigation requirement indexes of root extension period mostly fluctuate around 0 value,and the irrigation requirement indexes of other growth periods are mostly above 0 value.In terms of spatial distribution,the effective precipitation in each growth period is more in the south and less in the north,while the water requirement is on the opposite.The irrigation requirement index is larger in the north and smaller in the south,indicating that the northern tobacco area is much more dependent on irrigation than the southern tobacco area.