Productivity, economics and nitrogen-use efficiency of specialty corn (Zea mays) as influenced by planting density and nitrogen fertilization

Abstract

A field experiment to study the effect of planting density and N level on pop corn and sweet corn ( Zea mays L.) was conducted during rainy season 2005 and 2006 at New Delhi. An increase in planting density recorded taller plants with reduced values of yield attributes of both pop corn and sweet corn. However, in sweet corn the number of cobs/ha increased with the increase in planting density. The planting density of 66,666 and 83,333 plants/ha re- corded 23.5 and 40.0% higher grain yield of pop corn compared with that of 55,555 plants/ha respectively. The cob and kernel yields of sweet corn however, improved significantly by 19.4 and 15.2% at a planting density of 83,333 over that of 66,666 plants/ha respectively, but further increase in planting density to 1,11,111 plants/ha de- creased both the cob and the kernel yields in comparison with 83,333 plants/ha. The net returns, net returns/Re invested, N uptake and N-use efficiency also showed a similar trend. The increase in N level up to 120 kg/ha re- sulted in taller plants with higher values of yield attributes of pop corn as well as sweet corn, which consequently resulted in higher yields and returns. The highest N uptake and residual soil N content were recorded at 120 kg N/ ha level. The N-use efficiency was the highest at 40 kg N/ha, and an increase in N level reduced the N-use effi- ciency. The results show that for getting higher yield and net return, pop corn and sweet corn should be planted at 83,333 plants/ha planting density and fertilized with 120 kg N/ha.