Berseem Clover: A New Forage For Dairying in Mexico

The Comarca Lagunaera is the most important dairying region in Mexico. It is located in the semi-arid north central zone (26°N, 103°W): altitude 1100 m as!, mean annual rainfall of 220 mm, mild winters with some frosts (-4 to -6°C). The winter forages used are Italian ryegrasses and oats. Since I 985, a new forage crop, berseem clover (Trifolium alexandrinum), has been studied. Berseem clover is an annual winter legume with a high nitrogen {N) fixation capacity and yield of high quality forage. During 2 consecutive years in field experiments comparing pure stands of berseem and ryegrass (Lolium multiflorum), and in mixtures of berseem and ryegrass, berseem outyielded the ryegrass: 14 v. 12 Mg/ha DM. The mixtures yielded as much as the berseem alone. There was more crude protein (average of the season) in the berseem and mixtures than in ryegrass alone: 250, 220 and 180 g/kg, respectively. Berseem clover did not respond to the N fertiliser, applied at 0, 80 and 160 kg N/ha over the whole season. In the mixtures, as the berseem proportion increased, the response to N decreased. This provided evidence of effective N fixation by the clover. It was estimated that berseem fixed 380-506 kg/ha of N during the season. Berseem was also compared with alfalfa hay, using a ruminal nylon bag technique. After 72 h digestion, berseem showed a higher DM disappearance rate than did alfalfa. Berseem clover produced 136 g/kg bypass protein compared with 484 g/kg from alfalfa.