Response of maize (<I>Zea mays </I>L.) cultivars to different levels of nitrogen application in Swaziland during the 1994 cropping season

Abstract

Nitrogen (N) is one of the most deficient element in highly weathered tropical and subtropical soils. Yet, N is one of the most important nutrient for maize growth and development. If deficient, maize yields are reduced. A field experiment was conducted to determine the response of four maize cultivars to different nitrogen levels at the Lowveld Experiment Station, Big Bend, Swaziland. Four Nitrogen rates consisting of 0 kgN/ha, 50 kgN/ha, 100 kgN/ha and 150 kg/ha and four varieties (PHB3435, SNK2943, CG4141 and PAN6479) were used in this study. The experimental design was a randomised complete block (RCB) with 4x4 factorial treatment arrangement and 4 replications. The data collected were subjected to analysis of variance (ANOVA) and means were separated by the Least Significant Differences (LSD) test. Grain yield was further analysed using the Yield Fit Model to obtain both the Most Economic Yield and the Most Economic N rate. The ANOVA showed that the grain yield varied significantly (P>0.05) with both varieties and nitrogen level. However, there was no significant varieties by nitrogen interaction, suggesting that all varieties responded similarly to N application. In general, grain yield and total dry matter increased with increase in N applied up to 100kg N/ha. There was very little or no further grain yield increase beyond 100kg N/ha application. PAN6479 was the highest yielding variety while CG4141 was the lowest. Based on these findings the three (PAN6479, SNK2943 and PHB3455) highest yielding varieties may be recommended to be grown in this region of the country. However, based on the Yield Fit Model the variety PAN6476 would be the most economical to grow in this region of the country.

UNISWA Jnl Agric Vol.10 2001: pp.12-21