缺苗断垄对机播夏玉米产量及产量构成因素的影响

为探讨缺苗断垄对机械化播种夏玉米的影响，在大田状态下设置2个品种不同缺苗断垄程度进行试验，并对缺苗级别、断垄级别、籽粒产量及其产量构成因素进行统计分析。结果表明，缺苗断垄引起产量降低的主要原因是株数和穗数减少，随着缺苗断垄级别的增加，株数穗数逐渐减少，产量逐渐降低。产量降低幅度小于缺苗断垄级别的增加幅度，在缺苗断垄率为10.00%～40.00%的情况下，产量降低幅度为3.60%～28.51%；在缺苗断垄率相同的情况下，鲁单981比郑单958的减产幅度大些。

Study on Yield and Its Component Factors of Mechanized Sowing Summer Maize(Zea mays L.)by Sparse Breaks Up

The effects of mechanized sowing summer maize（Zea mays L.）by sparse breaks up were explored with different varieties and grades sparse by field testing. The grade of deficiency seedlings and broken ridge and the yield with its component were discussed. The results showed as follows： the main causes of yield reduction by sparse breaks up were the ears decrease. With the adding of grade of sparse breaks up, the yield gradually decreased. The decreased amplitude of yield is less than the increased amplitude of sparse breaks up grade .On the situation of the grade among 10.00%～40.00%, decreased amplitude of yield is 3.60%～28.51%. The decreased amplitude of yield of Ludan 981was bigger than Zhengdan 958 with the same sparse breaks up.