冀东平原是小麦玉米一年两熟区,但由于无霜期较短,受热量资源不足的限制,种一季有余,种两季紧张。小麦玉米历来采用套种和直播两种方式,年际间产量波动较大,两作年产量一般在500～700(小麦250～350公斤,玉米300～350公斤),玉米的增产潜力发挥不出来。1989～1990年,我们研究采用麦茬玉米扒根矮化育苗移栽方法,延长玉米生长期20～25天, Jidong Plain is a year of wheat and wheat two crops a year, but because of frost-free period, limited by the lack of heat resources, more than a quarter of species, the two seasons tension. Wheat and corn have always been using intercropping and direct seeding in two ways. The annual output fluctuates greatly. The annual output of two crops is generally 500-700 (250-350 kg of wheat and 300-350 kg of corn), and the yield potential of corn can not be realized. From 1989 to 1990, we studied the method of transplanting dwarf nursery corn using wheat stubble to prolong the growth period of maize from 20 to 25 days,