以先玉335为试验材料，研究割苗（割苗处理为A1，不割苗处理为A2）和密度（6.0万、7.0万、8.0万、9.0万、10.0万株/hm²，分别用B1、B2、B3、B4、B5表示）互作对吉林省春玉米生长发育及产量的影响，以期为高密度栽培条件下提高春玉米产量提供新的技术途径。结果表明，随着种植密度的增加，生育进程推后，生育期延长1～7 d，株高、穗位高增加；茎粗、叶绿素含量、单株叶面积、棒三叶叶面积均降低；穗部性状有变劣的趋势，除百粒质量外，割苗处理在B1、B2、B3条件下各性状差异总体上均不显著，且优于常规种植（A2B1）处理；产量、穗收获率总体上均呈降低趋势,籽粒含水量总体上呈增加趋势。相同种植密度下，割苗使春玉米生育进程推后，生育期延长2～3 d；株高、穗位高、茎节数、单株叶面积、棒三叶叶面积、秃尖长（A1B5处理除外）降低；叶绿素含量、根数、茎粗、穗长、穗粗、行粒数、百粒质量、穗粒数、籽粒含水量均增加；大喇叭口期和吐丝期根冠比增加；穗收获率提高；产量极显著提高，其中，A1B1、A1B2、A1B3处理产量均极显著高于其他处理，分别比A2B1处理增产13.81%、24.13%、21.85%，其他处理均低于A2B1处理。综上，在种植密度6.0万～8.0万株/hm²条件下，适时割苗能增加春玉米产量。

 Taking Xianyu 335 as experimental material，the effects of cutting seedlings［cutting seedlings treatment( A1) ，non-cutting seedlings treatment(A2) ］and planting density［60 000(B1) ，70 000(B2) ， 80 000(B3) ，90 000(B4) and 100 000(B5) plants/ha］on the growth and yield of spring maize in Jilin Province were studied，so as to provide a new technical way for increasing spring maize yield under high density cultivation condition.The results showed that with the increase of planting density，the growth process was delayed，and the growth period was prolonged for 1—7 days; plant height and ear height increased; stem diameter，chlorophyll content，leaf area per plant and area of three ear leaves decreased; ear traits tended to deteriorate，which(except 100-grain weight) of cutting seedlings treatment were not significantly different under B1，B2 and B3 conditions，and superior to conventional planting treatment (A2B1) ; yield，harvest rate of ear decreased，and water content of grain increased on the whole.Under the same planting density，cutting seedlings delayed the growth process of spring maize，and prolonged growth period for 2—3 days; plant height，ear height，node number，leaf area per plant，area of three ear leaves and barren tip length (except A1B5 treatment) of cutting seedlings treatments decreased; chlorophyll content，number，stem diameter，ear length，ear diameter，grain number per row，100-grain weight，grain number per ear and water content of grain of cutting seedlings treatments increased; root shoot ratio of cutting seedlings treatments increased at big trumpet stage and silking stage; harvest rate of ear of cutting seedlings treatments increased; yield of cutting seedlings treatments extremely significantly increased，and the yields of A1B1，A1B2 and A1B3 treatments were extremely significantly higher than that of other treatments，which increased by 13.81%，24.13% and 21.85% compared with A2B1 treatment，respectively.To sum up，timely cutting seedlings could increase spring maize yield under the planting density of 60 000—80 000 plants/ha．