Trend analysis of effective precipitation in different growth stages of winter wheat in Huaihe River Plain

The Huaihe River Plain (HRP) is one of the main planting areas of winter wheat in China. Uncertain and erratic distribution of precipitation and the shortage of water resources are the major limitations to crop growth in this region. In this study, the spatial and temporal distributions of effective precipitation during the different growth stages of winter wheat in the HRP were examined using a daily precipitation time series of 53 years (1961/1962~2013/2014) from 42 meteorological stations. The effective accumulative temperature index method was used to interpolate the winter wheat growth period data (recorded by 4 representative agro-meteorological stations). The Mann–Kendall method was used to check the statistical significance of the trends. The following conclusions are based on these results. (1) The effective accumulative temperature index method can be used to interpolate the observed data. (2) The effective precipitation results show downward trends with magnitudes of 0~− 6 mm/decade for the majority of the stations during certain stages (the tillering date to the jointing date, the jointing date to the heading date, and the entire growth period). (3) Most of the stations show strong downward trends during the growth stages corresponding to the tillering date to the jointing date and the jointing date to the heading date but show insignificant trends during other stages. (4) The spatially averaged effective precipitation data show very strong downward trends during the tillering to heading stage and weak downward trends over the entire growth period.