Journal of Experimental Agriculture International

Aims: The objective of this study was to evaluate the efficiency of nitrogen utilization by corn cultivars for the production of green ears.

Study Design: Treatments were constituted by the combination of two nitrogen doses (0 and 90 kg ha^-1 N) and three corn cultivars (Cruzeta, Truck and AG 1051). The experimental design was the randomized block design, in a 2 x 3 factor scheme, with five replications.

Place and Duration of Study: The experiment was conducted at a garden of the Department of Plant Science of Federal Rural University of the Semi-arid, Mossoró, Rio Grande Norte state, Brazil, from February to May 2015.

Methodology: The following parameters were evaluated: plant height, insertion of the first ear, stalk diameter, number and the productivity of marketable husked/not husked green ears , and the indices of efficiency agronomic efficiency, physiological efficiency, ear production efficiency, recovery efficiency and use efficiency.

Results: It was observed that application of nitrogen increased the plant height, insertion of the first ear, dry matter, number and the productivity of green ears. Cultivars differed in terms of stem diameter, plant dry matter and prolificacy. The cultivar Truck exceeded others regarding the ear number (husked, non-husked and total). However, as for productivity, the cultivars differed significantly only in the production of marketable husked ears. There was a significant difference among the cultivars, regarding agronomic efficiency and recovery efficiency.

Conclusion: Based on the values of the nutritional efficiency indices, Cultivar AG 1051, was more effective in using nitrogen to produce green ears as compared to Cruzeta and Truck. The dose of 90 kg ha^-1 N recorded the higher yield of green corn than no nitrogen application.