Publications

Zhang, YL; Wu, ZY; Singh, VP; Lin, QX; Ning, SW; Zhou, YL; Jin, JL; Zhou, RX; Ma, Q (2023). Agricultural drought characteristics in a typical plain region considering irrigation, crop growth, and water demand impacts. AGRICULTURAL WATER MANAGEMENT, 282, 108266.

Abstract
Hydrological models and drought indices based on simulation of soil moisture have been widely used in largescale agricultural drought assessments. However, hydrological models often oversimplify crop modules and does not consider irrigation, crop growth, and water demand impacts. Therefore, in the present study, a coupled hydrological-crop growth model Variable Infiltration Capacity - Environmental Policy Integrated Climate (VICEPIC) was used to consider the impact of the irrigation process on drought and propose a crop water anomaly percentage index (CWAPI) based on the crop water demand and consumption processes. Identification and assessment methods of drought events were also evaluated. The validation results of the VIC-EPIC model showed that the correlation coefficients between the MODIS evapotranspiration and the simulated evapotranspiration at 37% merged grids were above 0.74. The correlation coefficient (0.79) of the CWAPI-simulated values and statistical values of drought area rates was greater than that (0.72) of soil moisture anomaly percentage index (SMAPI), indicating that the simulation of drought area rate based on CWAPI was more reasonable. After identifying regional drought events and comparing the identified characteristic values of these events with the average drought data of each city, it was found that SMAPI misjudged some regions with high hydraulic conductivity as severe drought regions. This limitation was overcome by CWAPI, which directly reflects the degree of crop water shortage and considers the impact of irrigation on drought. Agricultural drought occurs due to low soil water content, which is caused by rapid percolation of soil water and insufficient storage of local and irrigation water. This study of drought indices will help develop a more timely and comprehensive adaptive strategy to deal with droughts by considering the impacts of irrigation, crop growth, and water demand on drought.

DOI:
10.1016/j.agwat.2023.108266

ISSN:
1873-2283