EFFECT OF NITROGEN FERTILIZER AND HARVESTING DAYS ON YIELD AND QUALITY OF RHODES GRASS (Chloris gayana) UNDER IRRIGATION AT GEWANE, NORTH-EASTERN, ETHIOPIA

Abstract

The experiment was undertaken to assess Rhodes grass yield and nutritional quality at different harvesting days and levels of N fertilizer application grown under irrigation at Gewane, Afar region. The field experiment was arranged in a 3 x 4 factorial randomized complete block design with three replications. The treatments were three levels of harvesting days (60, 90 and 120 days) and four level of N fertilizer application (0, 23, 46 and 69 kg ha-1 ). Plant height (PHT), number of tillers per plant (NT), number of leaves per plant (NLP), length of leaves per plant (LLP), leaf to stem ratio (LSR), number of internodes per plant (NIP), length of internodes per plant (LIP), number of internodes per tiller (NIT), DMY and CPY significantly (P < 0.01) increased as the level of N fertilization and days of harvesting increases. However, except for the length of internodes per plant (LIP), interaction effect is not significant for all the parameters listed above. The highest mean dry matter yield (DMY) recorded was 17.58 and 16.54 ton ha-1at 120 days of harvesting and 69 kg ha-1N fertilizer rates, respectively. The crude protein content (CP), calcium (Ca), phosphorus (P), and total ash content significantly (P < 0.01) increased as the level of N fertilization increases but declined as days of harvesting increases; however, except for the crude protein(CP) interaction effect is not significant. The dry matter content (DMP), neutral detergent fiber (NDF), acid detergent fiber (ADF),acid detergent lignin ( ADL), in vitro dry matter digestibility (IVDMD) were significantly different (P<0.01), for harvesting days and N fertilizer rates; however, except for NDF, interaction effect is not significant for all mentioned. The highest mean CP content recorded was 15.65% and 15.24% at 60 days of harvesting and 69 and 46 kg ha-1N fertilizer rate. The highest mean IVDMD recorded was 65.10% and 57.11% and 56.62% at 60 days of harvesting and 69 and 46 kg ha-1N fertilizer rate, respectively. Chloris gayana with N fertilizer application of 69 kg ha-1 and 120 days of harvesting was recorded high dry matter yield; while N fertilizer application of 69 kg ha-1 and 60 days of harvesting had more crude protein content and IVDMD. So, the results obtained in the present study revealed that optimum stage of harvesting at 90 days and 69 kg ha-1levels of N fertilizer application can play important roles in improving yield and nutritive value of Rhodes grass