Yield Response of Popcorn (Zea mays L. var. everta) to Nitrogen and Lime Amendment in a South Eastern Rainforest Environment of Nigeria

Two year field experiment was conducted during the early rainy seasons of 2009 and 2010 at the Teaching and Research Farm of the University of Calabar, South Eastern rainforest agroecology of Nigeria, to evaluate the response of popcorn (Zea mays L. var. everta) variety Ashland to four levels of nitrogen (0, 40, 80 and 120 kg N ha-1) and three levels of lime (0, 500 and 1000 kg ha-1). Factorial combinations of the treatments were laid out in a split- plot design with three replications. Results showed that increasing nitrogen levels from 0-120 kg N ha-1 significantly increased growth parameters and grain yield in 2009 and not beyond 80 kg N ha-1 in 2010. There was no yield response to lime application in 2009, whereas the 500 kg ha-1 lime rate gave the highest grain yield in 2010. Agronomic efficiency of N was increased at 500 kg ha-1 lime. Lime amendment was effective in reducing the rate of N applied to popcorn with high yields.