Effect of climate change on maize production in Northeast China
气候变化对东北地区玉米生产的影响

This paper analyzed the facts of climate change and its effects on the maize production in Northeast China according to the meteorological,maize yield and planting area data.The results are as follows.The heat resources in this region have been increasing continually since 1971.The accumulated temperature over 10℃ has increased by 262.8℃ averaged for the whole region.The plain area with accumulated temperature(≥10℃) higher than 2700℃ has extended northward 200-300 km,and eastward 50-150 km respectively.The precipitation in growing period(from April to September) during 1981-1990 had an increasing trend,but has been decreasing continually since 1991.Annual average water deficiency amounts to 391.5 mm.Humid area is decreasing and the whole region has a drying trend.The early frost date(the date with the lowest temperature ≤0℃) has postponed 7-9 days,and the frostless period has prolonged 14-21 days,so the probability of frost disaster occurrence is reduced.The period with high probability of lingering low temperature disaster on maize was observed in the 1960s and 1970s,and the period with low probability started in the 1990s.Heilongjiang Province had a high probability of frost disasters.With the heat resources increasing continually,adaptive area of maize planting is growing,with its north boundary extending northward and eastward,so the adaptive seeding date comes earlier.With steady increase of maize planting area and yield,the total yield and total planting area will increase by 9,670,000 t and 720,000 ha per decade respectively. Although climate change has supplied more heat resources for maize production in Northeast China,it is enhancing drought.So,we should adjust maize distribution and varieties.Additionally,using irrigation engineering and dry-farming technology widely,and selecting varieties with disease-resistance,drought-endurance and strong stress-resistance are the important measures to realize sustainable development of maize production in Northeast China.