Spatio-temporal distribution characteristics of climatic suitability degree of maize in Western Liaoning Province from 1956 to 2010

Under global climate warming and drying, temperatures have increased to varying degrees around the world. Global warming has caused significant changes in agro-ecological environments, of which maize yield and quality have been found to be heavily influenced by meteorological factors. Therefore the analysis of the suitability degree to climate change of maize during growth period could provide an important guide for increasing agricultural production. Basis on a climatic suitability degree model for optimal maize production, daily meteorological data for 19562010 from eight meteorological stations in four cities in West Liaoning Province were analyzed. The analysis included the spatial and temporal distribution characteristics of climate suitability degree during the whole growth period and each individual growth stage of maize using spatial interpolation, Empirical Orthogonal Function (EOF) analysis and wavelet transformation analysis. The results showed that: 1) The suitability degrees of precipitation, sunshine and integrated climate followed a declining trend during the maize growth period from 1956 to 2010. The suitability degree of integrated climate dropped at sowing, emergence and maturity stages but rose at flowering stage. 2) The suitability degrees of both temperature and sunshine during the whole growth period of maize and the suitability degree of integrated climate during sowing and maturity stages tracked an increasing trend from south to north, from west to east, from west to southeast and northeast, and from northeast to southwest in West Liaoning Province. However, the suitability degrees of temperature and sunshine at emergence stage were in contrast to that of sowing, with a general declining trend from northwest to southeast and northeast. The suitability degrees of precipitation, integrated climate during the whole growth period of maize and integrated climate during flowering followed a “low-high-low-high” zonal distribution from north to south. The constraint factors during sowing, emergence and flowering were precipitation, sunshine and sunshine. 3) EOF analysis showed that the percentage anomaly of suitability degree of integrated climate during the whole growth period of maize in West Liaoning Province generally slightly declined in space from southwest to northeast. Wavelet transformation analysis suggested the time coefficient of first feature vectors of integrated climate suitability degree at 3 scales of oscillation period ― 1430 years, 814 years and 37 years.