GROWTH AND YIELD INDICES OF WATER EFFICIENT MAIZE (WEMA) IN RESPONSE TO NITROGEN FERTILIZER AND PLANT DENSITY IN DRYLAND OF SOUTH AFRICA

Abstract

For many years, the major research question of agronomists has been how to increase maize yield, while the predominant agronomic practices that affect maize yield are cultivar selection, nitrogen fertilization and plant density. This study aimed to assess the response of growth and yield indices of WEMA to nitrogen fertilizerrates and plant density in the dryland of South Africa. A field study was conducted over two planting seasons (2015/16 and 2016/17) in two localities (Taung and Molelwane) of North-West Province, South Africa. The trials comprised three plant densities: 33,333, 44,444 and 55,555 plants/ha and five nitrogen fertilizer rates: 0, 60, 120, 180 and 240 kg N/ ha as main and subplots, respectively. The experiment was laid out in a split-plot fitted into a randomized complete block design with four replicates in each site. The parameters measured were leaf area index, specific leaf area, number of ear/plant, grain yield and yield components. At the vegetative stage, maize sown at 44,444 plants/ha had the highest leaf area index and leaf area ratio (2.81 and 7.00 cm2/g). The 44,444 plants/ha had the highest stover yield (3,122 kg/ha) and shelling percentage (80.21%). In addition, the highest and most significant grain yield (5,334 kg/ha) and harvest index (0.64) were obtained in the plots supplied with 180 kg N/ha. Therefore, WEMA maize should be cultivated with 44,444 plants/ha and the application of 180 kg N/ha for high grain yield in the dryland of South Africa.