title: A comprehensively quantitative method of evaluating the impact of drought on crop yield using daily multi-scale SPEI and crop growth process model.
abstract: The quantitative evaluation of the impact of drought on crop yield is one of the most important aspects in agricultural water resource management. To assess the impact of drought on wheat yield, the Environmental Policy Integrated Climate (EPIC) crop growth model and daily Standardized Precipitation Evapotranspiration Index (SPEI), which is based on daily meteorological data, are adopted in the Huang Huai Hai Plain. The winter wheat crop yields are estimated at 28 stations, after calibrating the cultivar coefficients based on the experimental site data, and SPEI data was taken 11 times across the growth season from 1981 to 2010. The relationship between estimated yield and multi-scale SPEI were analyzed. The optimum time scale SPEI to monitor drought during the crop growth period was determined. The reference yield was determined by averaging the yields from numerous non-drought years. From this data, we propose a comprehensive quantitative method which can be used to predict the impact of drought on wheat yields by combining the daily multi-scale SPEI and crop growth process model. This method was tested in the Huang Huai Hai Plain. The results suggested that estimation of calibrated EPIC was a good predictor of crop yield in the Huang Huai Hai Plain, with lower RMSE (15.4 %) between estimated yield and observed yield at six agrometeorological stations. The soil moisture at planting time was affected by the precipitation and evapotranspiration during the previous 90 days (about 3 months) in the Huang Huai Hai Plain. SPEIG90was adopted as the optimum time scale SPEI to identify the drought and non-drought years, and identified a drought year in 2000. The water deficit in the year 2000 was significant, and the rate of crop yield reduction did not completely correspond with the volume of water deficit. Our proposed comprehensive method which quantitatively evaluates the impact of drought on crop yield is reliable. The results of this study further our understanding why the adoption of counter measures against drought is important and direct farmers to choose drought-resistant crops.
authors.affiliation: Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing Normal University, Beijing, China.|College of Environment and Resource, Fuzhou University, Fuzhou, China.|Center for Drought and Risk Research, Beijing Normal University, Beijing, China.
authors.forename: Qianfeng
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing Normal University, Beijing, China. jjwu@bnu.edu.cn.|Center for Drought and Risk Research, Beijing Normal University, Beijing, China. jjwu@bnu.edu.cn.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing Normal University, Beijing, China.|Center for Drought and Risk Research, Beijing Normal University, Beijing, China.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Li
authors.affiliation: Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing Normal University, Beijing, China.|Center for Drought and Risk Research, Beijing Normal University, Beijing, China.
authors.forename: Hongkui
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing Normal University, Beijing, China.|Center for Drought and Risk Research, Beijing Normal University, Beijing, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Yang
authors.affiliation: Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing Normal University, Beijing, China.|Center for Drought and Risk Research, Beijing Normal University, Beijing, China.
authors.forename: Guangpo
authors.initials: G
authors.lastname: Geng
authors.affiliation: Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing Normal University, Beijing, China.|Center for Drought and Risk Research, Beijing Normal University, Beijing, China.
authors.forename: Xueli
authors.initials: X
authors.lastname: An
authors.affiliation: Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing Normal University, Beijing, China.|Center for Drought and Risk Research, Beijing Normal University, Beijing, China.
authors.forename: Leizhen
authors.initials: L
authors.lastname: Liu
authors.affiliation: Community and Regional Planning Program, University of Nebraska-Lincoln, Lincoln, USA.
authors.forename: Zhenghong
authors.initials: Z
authors.lastname: Tang
mesh_terms: D002681:China; D055864:Droughts; D008962:Models, Theoretical; D018526:Plant Transpiration; D014908:Triticum / Q000254:growth & development* / Q000502:physiology
keywords: Crop growth process model; Drought; EPIC; Evaluating; Huang Huai Hai Plain; SPEI