Effect of Nitrogen and Sowing Methods on Growth, Yield and Yield Efficiency of Three Maize (Zea maysL) CultivarsUnder Irrigation

Abstract

The experimental work of this study was conducted during the seasons of 2013/2014 and 2014/2015 in the Farm of the Faculty of Agricultural Sciences, University of Dongola, Northern State, Sudan. The objective of the study was to assess the effect of nitrogen levels ( 0, 43, 86 and 129 kg/ha) and sowing methods ( on ridges and on the flat) on growth, yield and yield efficiency of three maize ( Zea mays.L) cultivars (Hudeib-1, Hudeiba-2 and Dongola). The experiment was conducted on high terraces soil (Aridisols) in the Northern State of Sudan. A randomized complete block design in a split-split plot arrangement with four replications was used to layout this experiment. The three open-pollinated maize cultivars were assigned to the main plot ,the two types of sowing methods were assigned to subplots and the four levels of nitrogen were assigned to sub-subplots. The vegetative growth characters of maize which were investigated in this study were plant height, stem diameter, days to 50% tasselling, number of leaves per plant, leaf area index and days to maturity. Yield and yield components characters were number of seeds per row, number of rows per cob, number of seeds per cob, number of cobs per plant, number of cobs per meter square, cob length, thousand seeds weight, roots weight, grain yield and harvest index. Maize quality characters included crude protein and crude fiber and the efficiency characters included nitrogen use efficiency and agronomic efficiency. With the exception of plant height after 60 days, stem diameter after 60 days and days to maturity which showed insignificant differences in both seasons, the statistical analysis of variance indicated that the increase in nitrogen levels significantly increased most the of vegetative growth characters in the first season namely plant height and stem diameter after 90 days, days to 50% tasselling, number of leaves per plant and leaf area index. Also, the four nitrogen levels revealed significant differences in some of yield components namely thousand seeds weight, roots weight and harvest index in both seasons in addition to cob length which showed significant differences in the second season. On the other hand, other characters showed insignificant differences and these included number of seeds per row, number of rows per cob, number of seeds per cob, number of cobs per plant and number of cobs per meter square in both seasons. In addition, grain yield increased significantly and nitrogen use efficiency decreased significantly with the increase in nitrogen level in both seasons. Moreover , the analysis of variance indicated a highly significant effect of nitrogen levels on crude protein and crude fiber in the second season. Significant differences between the two types of sowing methods were revealed in some characters namely stem diameter after 90 days, days to maturity, number of seeds /cob and cob length in both seasons and leaf area index, thousand seeds weight and harvest index in the first season and days to 50% tasselling, number of seeds per row, crude fiber content ,nitrogen use efficiency and agronomic efficiency which showed significant differences in the second season. Also, there were significant differences among maize cultivars in some vegetative growth characters in both seasons namely plant height after 60 days, days to 50% tasselling, leaf area index and days to maturity in addition to some characters namely plant height after 90 days, stem diameter after 60 days, stem diameter after 90 days and number of leaves/plant which showed significant differences in the first season. Also , the analysis of variance indicated significant differences among maize cultivars in most of yield and yield components in both seasons with the exception of number of rows/cob which showed significant differences in the first season. Moreover , the analysis of variance indicated significant differences among maize cultivars in nitrogen use efficiency in both seasons and agronomic efficiency in the first season and crude fiber which exhibited significant differences in the second season.