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

Wang Xinning; Ren Yongjian; Zou Congpeng; Qin Pengcheng

doi:10.16765/j.cnki.1673-7148.2023.06.010

Abstract：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 tobac-co-planting region of Hubei Province from 1975 to 2021 are selected to calculate the effective precipitati-on,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 to-bacco area also shows a slowly increasing trend,but the variation amplitude is small.In general,the irriga-tion 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 irri-gation than the southern tobacco area.