Effect of rate and time of fertiliser nitrogen application on total plant, shoot, and root yields of maize (zea mays l.)

Abstract

Nitrogen at 0, 84, 168, 336, and 672 kg/ha was applied as liquid urea to a commercial maize cultivar (PX610) over three different growth stages. Plants were grown at a population of 96 900/ha and received continual trickle irrigation. Response was measured in terms of dry matter and nitrogen yields of the whole plant, leaf laminae, stem, cob, grain, husk, and roots. Overall yields of grain (11 000–14000 kg/ha) and total plant dry matter (24 000–29 000 kg/ha) at physiological maturity were high, but dry weight responses to different levels of nitrogen and times of application were not significant. Nitrogen content of the whole plant increased significantly with increasing nitrogen application rate. Dry matter and nitrogen concentration in the plant components changed in relation to changes in source-sink patterns as reproductive development began. Plants receiving 0 and 84 kg fertiliser N/ha showed classical nitrogen deficiency symptoms from late vegetative growth to maturity, but were the most efficient in using available nitrogen for grain production. © 1978 Taylor & Francis Group, LLC.