Utilization of Thinned Sunflower and Soybean Intercrops as Forage: A Useful Strategy for Small Scale Farms in Intensive Agricultural Systems

Abstract

Multipurpose intercropping, as a way of agricultural intensification, would contribute to solving the food and feed shortage problems facing the developing countries. In Northern Egypt, a 2-year field study was conducted to investigate the forage potential, in terms of productivity and quality, of thinned sunflower and soybean intercrops, that were subjected to three nitrogen (N) fertilizer rates (70, 105, 140 kg N ha−1) and three ages at forage removal (thinning); 15, 30, and 45 days after sowing (DAS) for sunflower, and 30, 45, and 60 DAS, for soybean. Altering N rate exerted limited effect on the studied sunflower and soybean forage parameters. Dry matter (DM) content of sunflower (157.14 g kg−1) and crude protein (CP) content of sunflower (120.48 g kg−1) and soybean (162.49 g kg−1) were significantly increased, while soybean NDF content significantly decreased, with increasing the N rate. The effect of age at forage removal was more pronounced as it is a direct reflection to the crop’s stage of maturity at cutting. Older sunflower and soybean plants were characterized by higher herbage yield, DM and fiber contents, yet lower CP than younger plants. Maximum herbage yield achieved with late cutting of sunflower and soybean amounted to 9.82 and 10.81 t ha−1, respectively. Relative feed value of sunflower and soybean herbage was less stable in response to the variations in the studied treatments, while, relative forage quality resulting from all treatments was graded as “premium”, making them suitable for high-producing dairy cows and young calves in intensive dairy production systems.