EFFECTS OF VARIETY AND CUTTING INTERVAL ON AGRONOMIC PERFORMANCE AND CHEMICAL COMPOSITION OF ALFALFA (Medicago sativa L.) UNDER IRRIGATION IN CENTRAL GONDAR ZONE, ETHIOPIA

<p><strong>Background:</strong> Understanding the relationship between dry matter yield production and forage quality throughout the growing season will help to optimize the cutting intervals between harvests in different alfalfa <em>(Medicago sativa</em> L.) varieties. <strong>Objective:</strong> To assess the effects of harvest frequency on forage yield and quality of 2 improved cultivars (ILRI-6984 and variety DzF-552) of alfalfa (<em>Medicago sativa</em> L.). <strong>Methodology: </strong>Two improved alfalfa (<em>Medicago sativa</em> L.) cultivars (ILRI-6984 and variety DzF-552) and four harvest frequencies (every 30, 40, 50, and 60 days) were combined and used for the study. A factorial experiment was laid down in a Randomized Complete Block Design (RCBD) with four replications<strong>. </strong>To assess their production potential plant height (cm), number of branches per plant, fresh biomass yield (t ha<sup>-1</sup>), and dry matter yield (t ha<sup>-1</sup>) of the forage and its nutrient content were recorded. The data collected were subjected to analysis of variance (ANOVA) by using the general linear model (GLM) procedure in Statistical Analysis System (SAS) (2003) version 9.1. <strong>Results:</strong> The highest forage dry matter yield was recorded for variety ILRI-6984 harvested every 40 d (26.8 t DM ha<sup>-1</sup>) and for variety DzF-552 when harvested every 60 d (24.1 t DM ha<sup>-1</sup>). While crude protein concentration tended to decline as age at harvest increased, there was little consistency in the pattern. Crude protein yields were also inconsistent across treatments but ILRI-6984 harvested every 40 d produced the highest yields (6.5 t ha<sup>-1</sup>). <strong>Implications:</strong> The present study contributes to the understanding of the relationship between dry matter yield production and forage quality in optimizing the cutting intervals between harvests in different Alfalfa (<em>Medicago sativa</em> L.) varieties. <strong>Conclusion:</strong> These preliminary findings need to be confirmed under field conditions on a large scale along with longer-term studies to examine the longevity of the stands at these harvest frequencies. Irregular harvesting based on the stage of maturity should be compared with fixed inter-harvest intervals.</p>