Impact of Vicia ervilia Ecotypes, Seedling Date, Dose, and Cutting Stage on the Nutritive Value of Bitter Vetch Ecotypes

In Morocco, livestock production faces significant challenges, such as drought and rangeland degradation, which reduce feed availability. To address this, alternative feed resources such as Vicia ervilia (bitter vetch) have been explored owing to their drought tolerance and ability to grow on poor soils. Bitter vetch is traditionally used for grain production, with a high protein content (~27% DM) and yields of up to 1 ton/ha, but its potential as a high-quality forage has been less studied. This study evaluated the expansion of bitter vetch use beyond grain, aiming to optimize cultivation practices for forage production under Mediterranean conditions in northern Morocco during the 2020/2021 season. A randomized block design with a split-plot arrangement tested three sowing dates (early, Dec 24; mid, Jan 10; late, Feb 1), four plant densities, and three ecotypes differing in flowering time (early, medium, and late). Plants were harvested at three flowering stages (start, full, and end), dried, ground, and analyzed for chemical composition, fiber fractions, and digestibility using standard methods. The results showed no significant effect of ecotype or sowing density on nutritive value, but sowing date influenced all measured parameters, and flowering stage affected fiber content (CF, ADF, cellulose) and dry matter digestibility. Early sowing reduced fiber content but did not lead to the highest organic matter digestibility, possibly due to fiber-digestibility relationships. Surprisingly, plants harvested at the start of flowering had the highest fiber content, and digestibility was lower at full flowering, potentially owing to inflorescence metabolites affecting rumen microbes. In conclusion, medium sowing combined with harvest at the start or end of flowering optimizes bitter vetch nutritional quality and fiber digestibility. These findings suggest that adjusting cultivation practices can enhance the value of bitter vetch as a sustainable alternative forage in drought-prone Moroccan regions, thereby supporting livestock production under challenging environmental conditions.