First Harvest Phenological Stage Effects on Production of Eight Irrigated Grasses

Phenological development stage at the first harvest affects seasonal dry matter production of some grass species. This field experiment was done to determine the effect first harvest phenological stage has on seasonal dry matter production of eight grasses under irrigation on the Central High Plains. Grasses were ‘Latar’ orchardgrass (Dactylis glomerata L.), ‘Fawn’ tall fescue (Festuca arundinacea Schreb.), ‘Regar’ bromegrass (Brontus biebersteinii Roem. and Schult.), ‘Manchar’ bromegrass (B. inermis Leyss.), ‘Gamson’ creeping foxtail (Alopecurusarundinaceus Poir.), meadow foxtail (A. pratensis L.), ‘Luna’ pubescent wheatgrass Agropyron trichophorum (Link) Richt.], and ‘Greenar’ intermediate wheatgrass p. intermedium (Host) Beauv.]. Soil of the study area was an Altvan fine sandy clay loam, an Aridic Argiustoll. First harvests of the grasses were made at the vegetative, boot-heading, and anthesis stages of development. In 24 species by year combinations, dry matter production was greater for first harvest at the boot-heading stage than for vegetative and anthesis stages by eight and five harvests, respectively. First harvest at the anthesis stage had greater dry matter production than for boot-heading in only one instance. First harvest at the vegetative stage depressed seasonal dry matter production. Crude protein and in vitro dry matter digestability (IVDMD) production generally followed the dry matter yields of the forages. Since the foxtail grasses have an indeterminate heading stage, a forage height of 25 to 30 cm appeared to be the best guide for first harvest of the growing season. The foxtail grasses, Latar orchardgrass, Fawn tall fescue, and Regar meadow bromegrass gave consistent season long production. The wheatgrasses and Manchar smooth bromegrass produced little regrowth and can he used to the best advantage in a forage program where hay harvest at the flowering staee is oracticed.