Impacts of climate change on water requirements of winter wheat over 59 years in the Huang-Huai-Hai Plain

Abstract

Daily data from 40 meteorological stations in the Huang-Huai-Hai Plain from 1955 to 2013 were analyzed using the Mann-Kendall test and partial correlation to determine the temporal trends of meteorological factors and their impacts on water requirements of winter wheat in different growing periods. Results showed that water requirements during the whole growing period in the Huang-Huai-Hai Plain were between 374 and 485.2 mm with an average of 412 mm in the past 59 years. In general, the value declined by 4 mm per decade. The distribution was ribbon-like, decreasing from the N to the S. Average wind speed, humidity, and sunshine hours declined significantly (α = 0.01, 0.05, and 0.01, respectively). Average vapour pressure and temperature increased significantly (α = 0.01). Only rainfall in Dongtai, Gaoyou, and Zhumadian could meet the water requirement of winter wheat over the whole growing period. Response of crop water requirement (ETc) to meteorological factors change was linear and the order of impact on ETc was vapour pressure, temperature, wind speed, and sunshine hours, while humidity had little impact on ETc. Among the impacting factors, vapour pressure was in positive relation with ETc.