The Simulation Of Crop Yield And Soil Moisture Uunder Climate Change On The Loess Plateau

Winter wheat and spring maize are the main crops on the Loess Plateau.In this research,we studied the effects of climate change on the yield and soil moisture of wheat and maize by using crop models of EPIC and APSIM.Firstly,we studied the dynamics of crop yield and soil moisture during 1981-2017 by using EPIC model and recognized the most influential climatic factor.Seoncdly,we combined the CMIP5 dataset and APSIM model to conduct the research about the dynamics of suitable planting area in the future(2020-2100).The main conclusions were as follows:(1)The precipitation amount during fallow period was critical factor to the sustainability of soil moisture.The lack of precipitation in successive seasons during fallow period would lead to the irreversible decrease of soil water storage.(2)During 1981-2017,the available soil water of spring maize and winter wheat field increased gradually in the early stage of simulation,then decreased significantly,and fluctuated with the precipitation in the final simulation period.The available soil water of spring maize field in the latest of continuous cropping period was greater than that in winter wheat field.In according to avoid the soil dryness,14 and 12 seasons are the largest recommended planting year for winter wheat and spring maize under the continuous increasing air temperature condition.(3)Precipitation is the most influential climatic factor for winter wheat yield(yield and yield stability)and soil moisture on the Loess Plateau.With the increasing temperature and decreasing precipitation,soil moisture will gradually be lower,and it will reduce the alternating frequency of soil dryness and wetness,meanwhile prolonged the low soil moisture.The increase of atmospheric carbon dioxide concentration can improve the moisture of the whole soil layer,and it was not enough to change the alternating frequency.However,it could extend the duration of high soil moisture(4)Under two representative concentration pathways(RCP 4.5 and RCP 8.5),the wheat yield and yield stability will increase significantly.The suitable planting area of winter wheat on the Loess Plateau will be expanded to the north part especially under RCP 8.5.