As climate changes, suitability zones for the cultivation of some crops may shift. In Northeast China (NEC), it is critically important for the agricultural community (e.g. farmers, advisors) to understand the potential shift in suitable cropping zones for spring maize in order to adapt to climate change. The potential climatic suitability can be defined as how actual temperature and solar radiation conditions match the requirements of crop growth under non-limited situations. Here, we used yield potential to reflect the potential climatic suitability, which is determined by the characteristics of crop, solar radiation, temperature, and photoperiod, given the assumption that water, nutrients, pests, and diseases are not limiting the crop growth. We assessed the annual yield potential of spring maize during 1961-2010 in NEC with APSIM-Maize. And then we analyzed the variations in potential climatic suitability zones and the possible effects of these variations on maize production potential. The results show that growing degree-days (GDD) during the growing season for spring maize universally increased in all the locations of this study during the period of 1981-2010 (period II) as compared to the period of 1961-1980 (period I). A total of 66 % of the locations show a decrease in accumulated sunshine duration (ASD) during the growing season during period II as compared to period I. Both coefficient of variation (CV) of GDD and CV of ASD showed an increase during period II as compared to period I. Under the background of climate change, the potential climatic suitability for spring maize was worsened during the most recent five decades: the yield potential declined and the yield stability decreased. In particular, most of the very suitable zone in Jilin and Liaoning during period I turned into suitable or moderately suitable zone during period II. Meanwhile, the total area of marginally suitable zone and no suitable zone increased by 16 % during period II as compared to period I. We detected a close correlation between the decrease in ASD and the decrease in potential climatic suitability, R = 0.56, p < 0.01. We also found a close correlation between the increase in GDD and the decrease in potential climatic suitability, R = -0.25, p < 0.05. Given the same crop varieties and farming management, the total production potential for spring maize in the entire NEC reduced by 4.3 % during period II as compared to period I.
Zhao, J; Yang, XG; Liu, ZJ; Lv, S; Wang, J; Dai, SW
Variations in the potential climatic suitability distribution patterns and grain yields for spring maize in Northeast China under climate change
Climatic Change