The above ground growth of Medicago truncatula, cvv. Cyprus and Jemalong, M. aculeata var. inermis, cv. SA 4438, M. orbicularis, cv. SA 2552 and M. rugosa, cv. Paragosa, grown in an irrigated field trial was analysed for crude protein content and in vitro digestibility. The genotypes concerned were established on three different planting dates, spaced c. 30 days apart, from the end of February to the end of April. Dried material collected at the beginning of flowering and at the onset of pod colouring was analysed.
At flowering, protein content varied from 12,8% in Paragosa, which was poorly nodulated, to 27,9% in SA 2552. The mean for all genotypes over plantings was 21,3%. At pod colouring the mean was 15,2%, with a range of 8,5% in Paragosa to 19,4% in SA 4438. The effect of planting date was negligible. If Paragosa is not taken into account, there was a clear positive relationship between growth period and protein production. At 2,3t/ha SA 4438 had the highest mean protein production at pod colouring..
The derived digestibility at flowering averaged 77,4%, ranging from 75,1% for SA 2552 to 80,6% for Paragosa. At pod colouring the mean was 67,9%, and the range 64,9% in Cyprus to 70,0% in SA 2552. Planting date had very little effect on digestibility.
Journal articles from the Grassland Society of Southern Africa (GSSA) African Journal of Range and Forage Science as well as related articles and reports from throughout the southern African region.