The Effects Of Different Climate Years On Tobacco Yield Were Studied Based On The AquaCrop Model

Tobacco is one of the important cash crops in China.Its growth and development are mostly affected by natural environment such as light,temperature and water.Yuxi is one of the main tobacco producing areas in Yunnan,and is known as the "hometown of cloud and smoke".In order to study the influence of meteorological factors on different growth periods and yields of tobacco in Yuxi and formulate a reasonable field management scheme,this paper selects the conventional meteorological data of 9 meteorological observation stations in Yuxi area from 1990 to 2019,finds out 11 factors representing the climatic characteristics of tobacco in each growth period,and carries out principal component analysis and systematic clustering to divide the climatic year types;Using the field measured data and meteorological data of Yuxi tobacco in 2019 and 2020 to drive the Aquacrop crop growth model,screen and optimize the crop parameters sensitive to the model,simulate the tobacco yield of 9 stations under different climatic year types,conduct the spatial simulation of tobacco yield in Yuxi area with the help of Arc GIS software,and analyze the change of yield.The main results are as follows:(1)The tobacco growth period in Yuxi area is divided into six main climatic year types,which are expressed by three independent principal component factors.In the past 30 years,the temperature of tobacco growing period gradually increased,the sunshine hours increased,and the precipitation decreased.The climate change in the root extension stage and quality formation stage of tobacco transplanting was more significant than that in the mature stage.The climate characteristics of different year types are obvious.From 1990 to 2008,the temperature during the tobacco growth period was low and there was more precipitation,which would be affected by low temperature and cold damage during the root extension period of transplanting.From 2008 to 2019,the temperature was generally high,resulting in high temperature and less precipitation during the whole growth period of tobacco,and tobacco growth was vulnerable to high temperature stress.The temperature variation range is small among different year types,and the variation range of precipitation and sunshine is large.(2)After Yuxi localization correction,Aquacrop crop model has certain applicability to the simulation of tobacco growth and development process.The EFAST method was used to analyze the global sensitivity of the crop parameters of the Aquacrop model.It was found that the crop parameters sensitive to the tobacco growth period process,above ground biomass and yield were mainly concentrated in the accumulated temperature required for each growth period,reference harvest index,canopy growth,attenuation coefficient,etc.After simulating the output of 9 tobacco planting stations,compared with the measured value,the test parameters are within the confidence interval,and the error between the simulated output and the measured output of each station is within 15%.(3)The main meteorological factors affecting tobacco yield in Yuxi area are the sunshine hours in the field growth period and the total precipitation from June to August.Based on the Aquacrop model,the tobacco yield under different climatic year types is simulated.During the tobacco growth period,the tobacco yield of the year type with insufficient light decreases by 8.3kg/ mu on average.In other periods,the light,temperature and water conditions are normal,and the tobacco yield increases by 8.7kg/ mu on average only in the year type with more precipitation from June to August.Based on the research results that the temperature of tobacco growing period rises slowly with time,the temperature after 10 years,20 years and 50 years is calculated with the climate tendency rate of 0.22 ? /10 a to simulate the tobacco yield.The results show that the tobacco yield tends to decline with the increase of temperature in different climate years.