Effect of nitrogen levels on growth and yield of popcorn maize (Zea mays var. everta) in Mid Hills, Parbat District, Nepal

Abstract

A field experiment was conducted from March to July 2020 to investigate the impact of varying nitrogen levels on the growth and yield of popcorn maize in Parbat. The experiment was laid out in single factorial Randomized Complete Block Design (RCBD) comprising nine levels of nitrogen: 0, 50, 75, 100, 120, 125, 150, 175 and 200 kg ha-1 as treatment with three replications. "Lumle Yellow" variety was cultivated in an acidic (pH 4.9) clay loam soil with moderate levels of total nitrogen (0.19%), high levels of available phosphorus (126.6 kg ha-1), potassium (427.68 kg ha-1), and moderate organic matter content (4.36%). The findings showed that an increased N-level significantly increased plant height and the leaf area index, reaching a maximum at 175 kg N ha-1. While number of cob plant-1 and kernel row cob-1 were non-significant, yield attributing parameters such as cob length, cob diameter, number of kernel rows-1, thousand grain weight, and grain yield were significant and determined to be maximum at 150 kg N ha-1. With subsequent increases in N to 175 and 200 kg N ha-1, the yield-attributing features did not show an increase. The highest grain yield (4.97 Mt ha-1) produced from 150 kg N ha-1 was 98 percent higher than the yield obtained from control (2.5 Mt ha-1) and 28 percent higher as compared to lowest level of N (50 kg ha-1). However, reduction in grain yield was found with increase in N levels above 150 kg ha-1