The study is carried out in Otluca Village bounding to city of Van in 2004-2005 years. In this study, it is aimed at investigating the possibilities of reducing amount of chemical nitrogen used in corn production which is planted before the vetch plant. In the 1st year of trial, in some part of the field, vetch is planted and its green herbage yield rates are determined. In the 2nd year of trial, planting activity is carried out in 2 trials as planting vetch both to the place it was previously planted and to where, it was not planted. In the trial, corn is applied chemical nitrogen in 5 different doses (0, 5, 10, 15 and 20 kg days(-1)). According to the results of the investigation, it is assigned that the corn, which is planted on the vetch, can be cultivated by using fertilizers with lower nitrogen. By the reduction in the amount of chemical nitrogen used, both the expenses will get lower and environmental pollution based on washing of fertiliser will be prevented. While, no difference is found on the corn planted after vetch that is applied 15 and 20 kg day(-1) nitrogen doses, in the corn, which is planted on the previously empty area, considerable difference is found between the doses. No considerable difference is found between 2 applications in terms of leaf, stem and ear ratios. The green and dry herbage yields at the corn, planted after vetch, vary between 5068.1 and 3033.3 and 1057.0 and 783.2 kg days(-1) respectively. However, these values at the corn, planted at the empty area in the preceding year, vary between 5134.4 and 2600.0 kg day(-1) and 1003.6 and 481.5 kg day(-1), respectively.