The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council. |
Monday, January 28, 2008
43
Lespedeza Seeding Rate and Nitrogen Fertilization Effects on the Yield and Botanical Composition of Crabgrass-Lespedeza Mixtures
Emily B. Aleshire, Department of Conservation and Recreation, Commonwealth of Virginia, 203 Governor Street, Richmond, VA 23219-2094 and Chris D. Teutsch, Southern Piedmont AREC, Virginia Tech, 2375 Darvills Road, Blackstone, VA 23824.
In the southeastern United States, many livestock producers contend with acidic soils low in fertility and a summer slump in the production of cool-season forage species. Crabgrass (Digitaria species, L.) and annual lespedeza (Kummerowia stipulacea, L. and Kummerowia striata, L.) are well-adapted to the less productive soils found in this region. Growing these species in a mixture could provide high quality summer forage. This study was designed to evaluate the effects of six lespedeza seeding rates (0 to 25 lb A-1) and two N fertilization treatments (125 lbs total N A-1 or no N) on the botanical composition and yield of crabgrass-lespedeza mixtures. Averaged over trials, lespedeza in the sward increased form 0 to 23% with lespedeza seeding rate when no N fertilizer was applied. The addition of N fertilizer greatly reduced the relative amount of lespedeza in the sward (< 10%). Crabgrass and other weedy summer annual grasses tended to increase with N fertilization. Lespedeza seeding rate had no effect on total yield. In contrast, N increased season total yield by an average of 36%. The results of the current study indicate that addition of annual lespedeza to crabgrass swards had limited effects on dry matter yield, while N fertilization increased yields regardless of lespedeza seeding rate. This finding is important since it indicates that producers using crabgrass-lespedeza mixtures should apply some N, possibly 60 to 100 lb A-1, to optimize dry matter production. More work is needed to better define the N requirement of this mixture.