THE EFFECTS OF PREVIOUS PLANTS AND NITROGEN RATES ON SECOND CROP CORN

The aim of this experiment was to investigate the effects of nitrogen (N) rates and previous crops on corn planted as second crops. This research was conducted in Kahramanmaras condition of second crop growing in 2007 and 2008. Split-split plot experimental design was used with four replications. Vetch and wheat were used as previous crops and N rates were used at 0, 12.5 and 25 kg/da for P 35Y65 and P.3394 hybrid corns. Tasseling period, plant height, 1000 grain weight, protein rate and grain yield parameters were evaluated. Results indicated that effects of years for tasselling period, plant height, and protein rate and grain yield of corn varieties were highly significant. There were significant differences between previous (vetch and wheat) for tasseling period, protein rate and grain yield of corn. Effect of N rates was also significant for tasseling period, 1000 grains yield and grain yield. There were significant differences between corn cultivars for 1000 grains yield and plant height. The results also indicated that protein rate and grain yield of corn seed were 7.94% and 919.13 kg/da respectively, when previous crop was wheat. The previous crop was vetch, protein rate of corn seed were 9.15% and 1010.84 kg/da. It was reported that the least grain yield was 838.55 kg/da with 0 kg/da N manure, the highest grain yield was 1032.22 kg/da with 25 kg/da N. It was showed that the previous crop was significant for corn. Keyword: corn, nitrogen rate, previous crop