Effects of swine manure application and row spacing on growth of pearl millet (Cenchrus americanus) during the establishment period and quality of silage produced in Southwest Nigeria

Abstract

The effects of swine manure application and row spacing on dry matter yields of Cenchrus americanus (pearl millet) at 6 weeks after sowing and chemical composition, fermentative characteristics and in vitro gas production of silage produced from the forage were studied. The design was a 2 × 2 factorial with 2 row spacings (0.5 and1.0 m) and 2 levels of manure application [no manure (Control) and swine manure at 5 t/ha (22% DM; 0.34% N on DM basis)] replicated 3 times. Swine manure application had no effect (P>0.05) on dry matter yield but a row spacing of0.5 m produced higher (P<0.05) dry matter yields than 1.0 m spacing (mean 7.05 vs. 5.57 t DM/ha). Fresh forage from manured treatments had significantly higher crude protein concentration (114.9–124.2 g/kg DM) than from unfertilized plots (86.2–95.1 g/kg DM). After being ensiled for 42 days, CP% in the forage had declined by 16–18% but relative differences remained. Quality measurements indicated that silages from the various treatments were all of acceptable standard although CP% of silage from Control plots was barely high enough to provide a maintenance diet. This study suggests that, under the experimental conditions, planting of pearl millet at a spacing of0.5 m rather than 1.0 m would increase DM yields obtained in the first 6 weeks of growth, while application of swine manure would not affect yields but would increase CP% of forage produced. The laboratory study indicates that the forage produced could be ensiled successfully although there was significant loss of crude protein during the process. Since there were no significant increases in DM yields of forage, other benefits, e.g. increase in N concentration, improved soil organic matter, etc., would need to be considered in justifying the additional cost of drying and applying the manure.