摘要
Based on county-level crop statistics and other ancillary information,spatial distribution of maize in the major maize-growing areas(latitudes 39°–48°N) was modelled for the period 1980–2010 by using a cross-entropy-based spatial allocation model.Maize extended as far north as the northern part of the Lesser Khingan Mountains during the period,and the area sown to maize increased by about 5 million ha.More than half of the increase occurred before 2000,and more than 80% of it in the climate transitional zone,where the annual accumulated temperature(AAT) was 2800–3400 °C·d.Regions with AAT of 3800–4000 °C·d became more important,accounting for more than 25% of the increase after 2000.The expansion of maize was thus closely related to warming,although some variation in the distribution was noticed across zones in relation to the warming,indicating that maize in northeast China may have adapted successfully to the warming by adjusting its spatial distribution to match the changed climate.