Fresh hairy vetches (Vicia villosa Roth) equivalent to 80, 160, and 240 kg N ha-1 were incorporated into soil at corn planting on Jungdong loam(coarse loamy, mixed, mesic, Typic Udifluvents) in Suwon, Korea for three years after one-year soybean rotation and were compared with each N amount of chemical nitrogen (N) fertilizer, ammonium nitrate (AN) to clarify the N effects on corn by different amounts of hairy vetch (HV). Soil properties for sustainable N management such as total C and N, microbial biomass N and mineralizable N were improved highly by HV incorporation while the content of mineralized N in soil was less in HV than AN during early decomposition of HV. Corn seemed to absorb more N from soil until after silk steadily in HV than AN judging from the higher stem nitrate at silk and increment of N uptake after silk. Increment of dry matter and N uptake by HV input were more than those by AN at the N levels of over 160 kg N ha-1 and those were linear in HV while being quadratic in AN though the corn N uptake in HV at N levels of under 160 kg N ha-1, particularly at 80 kg N ha-1 was less than that in AN. Apparent N use efficiency in HV was dropped slowly or increased a little with the rise of N level compared to the rapid drop in AN, and was similar or higher than that in AN at 240 kg N ha-1. This study demonstrates that a production system with HV amount of high N level can be superior to that with chemical N fertilizer of the same N level at the points of N use efficiency and potential for yield increase as well as sustainable soil N management in the continuous corn.