Growth and Yield of Sorghum as Influenced by Population Density and Time of Introduction of Component Cowpea

Abstract

A field trial was carried out at the Teaching and Research Farm of Kwara State University, Malete, Nigeria during 2018 cropping season to investigate the productivity and competitive behaviour as influenced by population density and time of introduction in sorghum/cowpea intercropping. Full population density of sorghum was combined with four population densities of cowpea (100S:100C, 100S: 75C, 100S: 50C and 100S: 25C where S and C represented sorghum and cowpea, respectively) at three period of introduction of cowpea (same time, two weeks after, and four weeks after planting). The treatments were arranged as 3 x 4 factorial combinations in split plot and replicated three times. Sole crop of both cowpea and sorghum were included in the treatment as a check. The number of branches of cowpea was found to decrease with the delayed in the time of introduction. The least grain yield of sorghum (1,160.84 kg/ha) and cowpea (583.38 kg/ha), respectively were recorded at 100S:100C and 100S:25C population ratios. The yield of sorghum increased with delayed in the time of introduction of cowpea irrespective of population ratio. The grain yield of cowpea reduced as the population density reduced and with further delayed in the time of introduction. The land equivalent ratio (LER)and land equivalent coefficient (LEC) demonstrated intercropping advantages at all population ratios tested when the two crops were simultaneously planted with the highest values, 1.23 and 0.38 for LER and LEC, respectively obtained at 100S: 75C population ratio. Regardless of population ratios and time of introduction, the aggressivity value was positive for sorghum and negative for cowpea and increased as the population of cowpea decreased and with delayed in the time of introduction of cowpea. Simultaneous planting of sorghum at full population with 75% population of cowpea was found better compared to other treatments and hence, recommended for adoption in sorghum/cowpea intercrop.