Differences among orchardgrass cultivars in response to hay and rotational grazing management

Abstract

This study was conducted to compare orchardgrass (Dactylis glomerata L.) cultivar performance under contrasting management systems (hay vs. rotational grazing) during the first two production years. The trial consisted of eight orchardgrass cultivars broadcast seeded in a randomized complete-block design, with three replications. The perimeter of each replication was fenced, and the area was divided into two sections. The first section was managed as a simulated hay production system. The second section was managed by simulating a rotational grazing system using crossbred ewes. Dry matter (DM) yield was determined before harvesting or grazing. Tiller density (TD) and leaf area index (LAI) were measured on four cultivars prior to harvesting and grazing. Excellent DM yield and persistence were obtained from all cultivars in both years under hay management but varied considerably under grazing management. Cultivar ranking according to DM yield under hay management was different from ranking based on performance under pasture management. One group of four cultivars had a decrease in yield of 19.9% in the second year of grazing, over the first year, but yield of the remaining group increased by 5.7% (SED = 9.83). Production of hay was similar for both groups. Early-maturing cultivars yielded 7% more DM and had higher crop growth rates (CGR), LAI and TD than late-maturing cultivars. Growth characteristics of orchardgrass cultivars as measured by DM yield, CGR, LAI and TD were modified by management practice. As a result, evaluating orchardgrass varieties under a hay management system was not effective in determining their performance under grazing. Key words:Dactylis glomerata, cultivar evaluation, cultivar development, grazing, yield, yield components