EFFECTS OF PLANTING DATE AND MODE OF NITROGEN APPLICATION ON THE GRAIN AND NUTRIENT YIELDS OF SORGHUM SK5912 (Sorghum bicolor (L.) Moench) IN THE SOUTHERN GUINEA SAVANNA OF NIGERIA

Abstract

Timeliness of all crop management factors is essential for realizing the yield potential and maximum profit in sorghum production. A field experiment was conducted on an alfisols in 2008 at the Old Teaching and Research Farm of the Federal University of Technology, Minna. To determine the appropriate planting date and mode of nitrogen (N) application for optimum grain and nutrient yield of sorghum (Sorghum bicolor (L.) var. SK5912). The experiment was laid out in a 2 x 4 x 3 factorial fitted into a Randomized Complete Block Design (RCBD), consisting of two modes of N application ((i) 90 kg N ha applied at 2 weeks after planting (2 WAP), and (ii) 45 kg N ha applied at 2 and 4 WAP respectively) and four planting dates namely: T1 (25th April) and T2 (3rd May) after 1st and 2nd rainfall within the Nigerian Meteorological Agency (NIMET) 2008 forecast of safe planting window for Minna area respectively, T3 (16th May) and T4 (9th June) were dates chosen after 1st and 2nd rainfall outside the NIMET safe window respectively. Results obtained showed that sorghum grain and N yield were significantly (p<0.05) affected by planting date and mode of N application. In general, grain and grain N yield of Sorghum var. SK5912 were significantly higher when sown within the NIMET predicted safe planting window and at 90 kg N ha applied at 2WAP than when sown outside the NIMET windows under split N application. This study therefore suggests that, seeds of Sorghum var. SK5912 can be grown on the field between 25th April and 3rd May with an application of 90 kg N ha at 2WAP for optimum yield within the study area.