Relationship of Simultaneous Cropping with Legumes and Application of Chemical and Biological Fertilizers with Agronomic Nitrogen Use Efficiency in Corn

In order to evaluate the effect of simultaneous cropping with legumes and application of chemical and biological fertilizers on nitrogen agronomic efficiency of corn، this study was carried out in field of agricultural research of Arak Payame Noor University in 2011. A factorial arrangement of treatments in a randomized complete block design with three replications was used. Methods of plant nutrition (M0= inoculation with azotobacter، M1= inoculation with azotobacter + 37. 5 Kg. ha-1 of rare nitrogen with foliar application method، M2= inoculation with azotobacter+150 Kg. ha-1 of rare nitrogen mix with soil) and simultaneous cropping treatment of legumes، (S1= corn + alfalfa، S2= corn + bitter vetch، S3= corn + mung bean، S4= corn + chickpea، S5= corn + vetch) were assigned in plots. Each sub plot consisted of 4 rows، 6 m long with 60 cm between rows space and 20 cm between plants on the rows and S. C Apex hybrid was used. Results showed that the methods of nutrition effect on the characteristics such as stem height، number of grain per ear، wet weight of ear، harvest index of legumes، biological yield of corn، productivity index، grain yield of legumes، nitrogen agronomic efficiency and yield of wet forage was significant. Effect of simultaneous cropping treatment on the number of green leaf، number of grain per ear، wet weight of ear، harvest index of legumes، biological yield of corn، productivity index، harvest index of ear، grain yield of legumes، nitrogen agronomic efficiency and yield of wet forage was significant. The maximum and minimum of yield of wet forage (52. 2 and 32. 2 ton. ha-1) were obtained with the inoculation with azotobacter + 150 Kg. ha-1 nitrigen + Simultaneous cropping of bitter vetch and corn and inoculation with azotobacter + non application of nitrogen + Simultaneous cropping of corn and alfalfa treatments، respectively.