Effects of plant population and soil amendment on growth and grain yield of grain amaranth (Amaranthus cruentus L.)

Experiments were conducted at the National Horticultural Research Institute (NIHORT), Ibadan, Nigeria in 2012 and 2013 cropping seasons to determine the effects of plant population and soil amendments on the growth and yield of two varieties of amaranth. The treatments consisted of two varieties of grain amaranth (TE81/28 and CEN18/97), three plant populations (100,000; 60,000 and 40,000 plants ha-1). Six levels of soil amendment (0, 25, 50, 75, 100kgN ha-1 of organic fertilizer and 100kgN ha-1 of inorganic fertilizer. The trials were designed as 2 x 3 x 6 factorial and laid out in split-split plots arrangement and repeated three times. Two varieties of grain amaranth (TE81/28 and CEN 18/97) as main plots, three plant population (100,000; 60,000 and 40,000 plants ha-1) as sub plots while six levels of soil amendments as sub-sub plots. Data collected on plant height, number of branches and grain yield were analyzed using the analysis of variance and treatment means separated by the least significant difference at 5% probability level. The results showed that though the organic soil amendment gave a progressive increase in the parameters measured with an increase in application levels, the in-organic soil amendment (100 kg N ha-1) significantly increased both the growth and yield parameters at 60,000 plants ha-1 with CEN18/97 amaranth variety.Keywords: Soil amendment, Growth and Yiel