Author
CUOMO, G - WCROC, UNIV OF MINNESOTA | |
JOHNSON, D - WCROC, UNIV OF MINNESOTA | |
Forcella, Frank | |
RUDSTROM, M - WCROC, UNIV OF MINNESOTA | |
MARTIN, N - UNIVERSITY OF MINNESOTA | |
LEMME, G - WCROC, UNIV OF MINNESOTA |
Submitted to: Journal of Production Agriculture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/1/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Many grazed pastures in the north central region of the United States are dominated by bromegrass and bluegrass, have low productivities, are not intensively managed, and receive few inputs. For four years, we studied the effects of renovation and intensive rotational grazing on such a pasture in central Minnesota. Pasture renovation treatments included no-till seeding of various legumes and a "graziers mix" of grasses and legumes. Rotational grazing treatments consisted of five to six short durations per season of intensive grazing meant to leave forage heights of 4, 6, or 8 inches. On average, grazing management that left plant heights at 6 or 8 inches produced 15% and 20% more forage than heavier grazing where plant heights were left at 4 inches. Interseeded legumes such as alfalfa and clover persisted for at least four years, and helped produce, on average, 46% more forage than the non-renovated bromegrass/bluegrass check treatment. In summary, frequent, light to moderate grazing of renovated pastures can enhance forage production for at least four years. Unfortunately, weedy thistles also increased with light grazing, but only in areas not renovated with legumes. These results will benefit farmers with dairy herds, as they show that low-productivity pastures may be renovated profitably with legumes and rotational grazing. Technical Abstract: Legumes increase production in cool-season grass pastures. However, they are included in relatively few acres of pasture. A split plot experiment with six replications was conducted to evaluate the impact of pasture renovation and grazing management on forage production and species composition of cool-season grass pastures. Grazing management main plots were grazed to leave low, medium or high (2 - 4, 4 - 6, or 6 - 8 in., respectively) residue levels. Main plots were intensively grazed (50,000 - 70,000 lb of cows/ac) 5 or 6 times per grazing season by lactating Holstein cows. Subplot pasture renovation treatments were 1) an untreated check, or sprayed with glyphosate and interseeded with 2) alfalfa, 3) red clover and birdsfoot trefoil, or 4) "graziers mix" (a mixture of legumes and grasses). Areas that were grazed to leave low residue produced less forage mass (4.7 ton/ac) than areas grazed to medium (5.4 ton/ac) or high (5.5 ton/ac) residue levels. When averaged over years and grazing management treatments renovated areas produced 1.8 ton/ac (46%) more forage than the control. Of interseeded species, alfalfa, red clover, and orchardgrass persisted through the study (more than 25% of the dry matter in at least one of the pasture renovation treatments). By June 1998, thistles were present in all treatments. Fewer thistles were present in areas that were grazed to leave low residue than high residue and in renovated areas than the control. The additional forage produced as a result of pasture renovation cost from $8.07/ton to $12.81/ton. This study indicates that pasture renovation can be a valuable tool for increasing forage production in cool-season grass pastures. |