华北平原小麦-玉米两作生产潜力与产量差

华北平原是我国粮食主产区，分析气候变化对该区小麦-玉米两作系统生产潜力的影响意义重大。本文采用EPIC模型估算了华北平原小麦-玉米两作的生产潜力，并结合实际产量计算了产量差。结果显示：（1）华北平原1961—2007年小麦-玉米两作潜在产量在19.7~22.2 t/hm2之间，区域均值为21.2 t/hm2；雨养产量在13.2~21.7t/hm2之间，区域平均值为16.4 t/hm2；（2）1960—2007年间，潜在产量在全区显著上升，年均增幅多在20~40 kg/hm2之间，雨养潜力在南部呈增加趋势，但北部呈下降趋势；（3）华北平原2001—2007年小麦-玉米两作的潜在产量和实际产量的差在20.3%~72.2%之间，区域平均值为潜在产量的48.2%。从空间分布上看，南部地区产量差较大，中部地区产量差较低，北部地区产量差居中。因此，自1960年来华北平原小麦-玉米两作还有很大的增产潜力，特别是水分状况较好的南部地区，应提高水肥利用效率，挖掘其增产潜力。

Yield Potential and Yield Gap of Wheat-maize Cropping System in the North China Plain

The North China Plain (NCP) is a main grain production base in China, therefore, it is very important to study the impacts of climate change on the production potential of wheat-maize cropping system in NCP. The yield potential of wheat-maize cropping system in NCP was simulated by EPIC model, and the yield gap was calculated according to the actual yield. The results were as following. (1) The potential and waterlimited yield for wheat-maize cropping system during 1961-2007 were 19.7-22.2 t/hm2 and 13.2-21.7 t/hm2, with the regional average of 21.2 t/hm2 and 16.4 t/hm2, respectively. (2) Both potential and water-limited yield of wheat-maize cropping system showed an increasing trend, with an annual increasing range from 20 kg/hm2 to 40 kg/hm2 and from -95.0 kg/hm2 to 70.2 kg/hm2, as affected by climate change. Meanwhile, the waterlimited potential increased in the south but had a decreasing trend in the north. (3) The yield gap between the potential and actual yield of wheat-maize cropping system from 2001 to 2007 was 20.3%-72.2%, with a regional average of 48.2%. In spatial distribution, the area of high yield gap located in the south, the area of low yield gap located in the middle, and the area of middle yield gap located in the north. As a result, there has been a large potential yield increase in wheat-maize cropping system in NCP since 1960, water and nutrient use efficiency should be improved in order to enhance the yield increasing potential in NCP, specially in the south of the region.