关键词: 东北三省, 玉米, 产量差, 时空特征

Abstract: 【Objective】 As the population increase, climate change and the environmental issues become increasingly prominent, food production and food security issues have attracted extensive attention. However, at present, the yields of crops are much lower than potential yields, therefore, how to produce enough food on limited land resources has become the major agricultural problem in China. Northeast China (NEC) is one of the most important maize production areas in China, where the maize output accounts for about 29% of the nation’s production. Therefore, increasing maize yield has undoubtedly played a vital role in securing food production in China. 【Method】 The yield gap between the potential yield and actual farmers’ yields of maize in Northeast China was studied on the basis of meteorological data, agro-meteorological observations, and agricultural statistical data during the period from 1961 to 2010, and by using the Agricultural Production System Simulation Model (APSIM-maize) and statistical method, which will provide a scientific basis for the ascension of crop production in NEC. 【Result】 The yield gap between potential and actual farmers’ yields (total yield gap) of spring maize decreased with increasing latitudes and longitudes (P<0.01). Among locations, this yield gap ranged from 4.8 t·hm^-2 to 11.9 t·hm^-2. The yield gaps between potential and attainable yields (yield gap 1), attainable and potential farmers’ yields (yield gap 2) showed a decreasing trend with increasing longitudes, showed a negative relationship with precipitation during the growing season. Among locations, mean yield gap 1 ranged from 0.06 t·hm^-2 to 3.2 t·hm^-2. And mean yield gap 2 ranged from 1.7 t·hm^-2 to 8.0 t·hm^-2, mainly due to the effects of management practices. The mean weighted yield gap between potential and actual farmers’ yields was 64% of the potential yield of spring maize. Moreover, 8%, 40%, and 16% reductions in potential yields were due to non-controllable factors, agronomic factors, and socioeconomic factors, respectively. During the past five decades, the yield gap of these four levels all showed a decreasing trend, total yield gap and yield gap 3 decreased by 1.55 t·hm^-2, and 1.40 t·hm^-2 per decade (P<0.01) in NEC, However, yield gap 1 and 2 showed no significant trend. 【Conclusion】 It was concluded that the yield gap between potential and actual farmers’ yields of spring maize decreased with increasing latitudes and longitudes, moreover, agronomic factors are the main constraints limiting maize yield in NEC, the yield gap could be deeply reduced by 40% by improving agronomic factors, including local management practices, soil conditions, and high-yielding varieties.

Key words: Northeast China, maize, yield gap, spatial-temporal variations