Effects of controlled release nitrogen fertilizer on dent corn (Zea mays L. Indentata Sturt.) grain yield and yield components

In order to study the effects of controlled nitrogen (Kurea) release fertilizer on grain yield and yield component of dent corn, an experiment was conducted at experimental area of field crops of Cukurova University during the main crop growing season (2012). The experiment was designed as a spilt-split plot based on randomized complete block design with four replications. The treatments could be summarized as follows, main plots included (a) sowing and [sowing+V6 growth stage], sub plots included (b) N levels (0, 15, 20, 25, 30, 35 kg N da-1) and sub-sub plots included (c) N fertilizer type (normal urea:Nurea and Kurea) The results showed that application of Kurea was reduced 2.7% of grain yield than Nurea. Grain yield increased with increased nitrogen rate up to 30 kg N da-1 beyond which no appreciable increase was observed. Relationship between basic grain yield, grain number and grain weight was not significant with one another. When the Nurea applied in the sowing time, grain weight was superiorly related with number of traits, but relationship between grain number with other traits were not significant to low levels. In conclusion, based on grain yield attributes, the optimal nitrogen fertilization rate (25 kg N da-1 to 30 kg N da-1) was the best suggestion to obtain highest maize grain yield.