Tropicultura (Jan 2007)
Nitrogen-use Efficiency of Maize Genotypes under Weed Pressure in a Tropical Alfisol in Northern Nigeria
Abstract
A split - split plot experiment in a randomized complete block design with three replicates was established at Samaru (Typic Haplustalf) in 2002 and 2003 rainy seasons to investigate the response of four low nitrogen tolerant maize (Zea mays L.) cultivars (Oba super II, Low N pool C2, TZB-SR and ACR 8328 BN C7) to nitrogen fertilizer and weed pressure. Maize grain yield, nitrogen-uptake, utilization and use efficiency were significantly higher in Oba super II and Low N pool C2 followed by ACR 8328 BN C 7 and least in TZB -SR. At the application rate of 90 kg N.ha-1, 68 kg N.ha-1 were recovered in maize shoot while weeds uptake of N was 15.98 kg.ha-1. With the application of 30 kg N.ha1, weed uptake was 28.38 while maize shoot uptake was 23.35 kg N.ha-1. Generally, fertilizer addition enhanced the competitive ability of maize. The nitrogen-use efficiency of the maize genotypes was reduced due to weed interference while there were no differences in the residual soil nitrate among nitrogen rates and genotypes, partly due to the morphology of the site.
