Effects of the stage of growth on the forage yield, quality and nutrient uptake of three varieties of Sorghum (Sorghum bicolor L. Moench) in a humid zone of Edo State, Nigeria

Abstract

A field study was conducted to investigate the effects of stage of growth on the forage yield, mineral composition and nutrient uptake of three sorghum varieties at the Teaching and Research Farm, Ambrose Alli University, Ekpoma. A 3×3 factorial design fitted into a Randomized Complete Block (RCB) was used. The three varieties of sorghum used were: Samsorg 16, 44 and 48 while the three stages of growth were: vegetative (6 WAP), flowering (12 WAP) and fruiting (16 WAP). Data were obtained on vegetative parameters, forage and dry matter yields. The mineral composition and nutrient uptake were also determined. The results showed that except for the number of tillersplant^-1, stage of growth significantly influenced the vegetative characters and yield of sorghum. Samsorg 16 at the fruiting stage had the highest forage (29.20 t ha^-1) and dry matter yields (14.85 t ha^-1). The macro-and micro-nutrients in the leaves of the crops were adequate except for Mn, Zn and Cu contents compared to the established critical levels for ruminant animal production. Samsorg 48 at fruiting and vegetative stages had the highest and least uptake of P, K, Mg, Ca and Na, respectively. However, considering the nutrient uptake, Samsorg 16 variety harvested at the fruiting stage is recommended as forage for livestock production and nutrition in this zone.