HERBAGE YIELD AND CHEMICAL COMPOSITION OF FOUR VARIETIES OF NAPIER (PENNISETUM PURPUREUM) GRASS HARVESTED AT THREE DIFFERENT DAYS AFTER PLANTING

Abstract

An experiment was conducted to assess the herbage yield and chemical composition of 4 varieties of Napier grass (Pennisetum purpureum) harvested at 3 different days after planting. The varieties tested were obtained from ILRI (formerly ILCA) were Local, 16798, 16786 and 16840 and used in a 4x3 factorial arrangement of treatments with four replicate plots each. The herbage yield of the varieties were measured at 60, 90, 120 days after planting. The herbage of the varieties were harvested and separated into leaf and stem fractions. The results indicated that, dry matter (DM) herbage yield was significantly (P<0.05) higher for variety Local (41050 kg DM/ha) and 16798 (44,994 kg DM/ha) when compared to the other varieties. Harvesting at 120 days gave a significantly (P< 0.05) higher herbage yield (46,013 kg DM/ha) with the 60 days giving the lowest (22,489 kg DM/ha). Measurement from the chemical composition for the four varieties indicated that the Local variety yielded the highest CP (96.77 g/kg DM) and cellulose (420.8g/kg DM) compared with the other varieties. Hemicellulose was highest for varieties 16798 (252.3g/kg DM) compared to the other three varieties. The ADL was lower for variety 16798 (89.0g/kg DM) compared to the other varieties. Measurement from the chemical composition for the three harvesting days indicated that the 60 days harvest gave the highest CP (109.88 g/kg DM), lowest ADL (84.13g/kg DM) and the lowest DM (478.5g/kg). The cellulose fraction was highest for the 60 days harvest (427.6g/kg DM) with 120 days harvest recording the lowest (354.6g/kg DM). The hemicellulose fraction was lowest for the 60 days and highest for the 120 days after planting. Measurement from the chemical composition for the two fractions indicates that the leaf fraction recorded a higher CP (122.24g/kg DM) and lower ADL (105.83g/kg DM) compared to the stem. The stem fraction however recorded a higher cellulose fraction (406.9g/kg DM) compared to the leaf fraction. Hemicellulose was higher for the leaf fraction (240.0g/kg DM) compared to the stem fraction. The ADL was lowest for variety 16798. The herbage yield increased with increase in days after planting. The DM, hemicellulose and ADL increased with increase in days after planting. Crude protein and cellulose for the three different days after planting however decreased with increase in days after planting.. The results showed that varieties Local and 16798 had the highest CP and cellulose but lowest ADL contents. As expected, CP declined with age and NDF, ADF and ADL increased with increasing age of the grasses. Similarly, herbage yields were highest for Local and 16798 varieties. As expected, herbage yield increased but CP declined with age of the grasses. The DM for the leaf and stem fraction was almost the same. The CP and hemicellulose were higher for the leaf fraction. The cellulose and ADL were all lower for the leaf compared to the stem fraction. The results show the potential of Local and 16798 varieties as a ruminant feed in Ghana.