Date of Graduation
Davis College of Agriculture, Natural Resources and Design
William B. Bryan.
Nitrogen (N) and defoliation effects on productivity, root growth and soil nitrate (NO3-) in a Kentucky bluegrass and white clover pasture were examined. Nitrogen was applied annually in two equally split applications at rates of 0, 80 or 160 kg N ha -1. After reaching 12.7 cm, plants were cut to 2.5, 5.1 or 7.6 cm. Herbage was analyzed for yield, crude protein (CP), neutral detergent fiber and acid detergent fiber. Root samples were divided into three depths: 0.0--5.1, 5.1--10.2 and 10.2--20.3 cm, and analyzed for volume, dry weight and length. Soil NO3- was measured. At the 2.5 cm cut yield and fiber concentrations were higher; CP concentration was lower. Roots in the top depth had lower volume, dry weight and length. When no N was added, CP concentration of herbage and soil NO3 - concentration were lower, and root volume and dry weight were lower in the 0.0--5.1 cm depth. Cutting to 2.5 cm stopped root growth; more herbage was harvested but the material was more mature, decreasing CP and increasing fiber.
Kertulis, Gina Marie, "Effects of nitrogen and cutting management on root growth and productivity of a Kentucky bluegrass (Poa pratensis L.) and white clover (Trifolium repens L.) pasture" (2001). Graduate Theses, Dissertations, and Problem Reports. 1257.