Rejuvenation of depleted pasture using bloat-free legumes for high performance cattle grazing
Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences
Direct seeding into existing pasture is expected to reduce time for rejuvenation and loss of productivity. To accomplish this, experiments were conducted to determine appropriate method of pasture rejuvenation using bloat-free forage legumes. Four sainfoin (Onobrychis viciifolia Scop.) and three cicer milkvetch (CMV) (Astragalus cicer L.) populations were seeded into alfalfa and grass pastures using three seeding methods to compare their ability to establish and persist in the mixtures. At Lethbridge where the old pasture was predominantly alfalfa, significantly higher (p<0.001) proportion of newly established plants were observed when the pasture was completely plowed and reseeded with both alfalfa and test populations (cultivation method) than directly seeding sainfoin or CMV for rejuvenation. Between the two test populations sainfoin contributed higher (p<0.05) proportions of plants to the pasture mix compared to the CMV populations. Two of the three new sainfoin populations, AAC Mountainview and LRC3432 seeded in alternate rows with alfalfa contributed >20% (p< 0.05) in total dry matter (DM) yield at each harvest. In grass pastures at Ponoka and Red Deer maximum biomass contribution from test populations when drilled were 2.3% and 8.2% respectively. Grass-legume mixtures with >10% legume stands increased soil available nitrogen in 2 years. Although in two years sainfoin and CMV mixed pastures did not sequester organic carbon in soil, they increased microbial carbon biomass and enzyme associated with C-cycling. Seeding of two sainfoin populations AAC Mountainview and LRC3432 into established alfalfa pasture could improve productivity of existing pasture while preventing bloat in grazing cattle.
Alfalfa , Bloat in animals , Fallowing , Legumes as feed , Sowing , Tillage