Effect of Grazing Stubble Height and Season on Establishment, Persistence, and Quality of Creeping Bluestem

Abstract

Creeping bluestem (Schizachyrium stoloniferum) was grazed every 60-days to 15 or 30-cm stubble heights during the following 4 periods (seasons): (1) June, Aug., Oct. (JAO); (2) Oct., Dec., Feb. (ODF); (3) Feb., Apr., June (FAJ); (4) year-long (YL). Average diameter (37 cm) of plants grazed in JAO and YL to 15-cm stubble was less (P<0.05) than plants (43 cm) grazed to 30 cm. There was no difference in diameter of plants grazed to 15 and 30-cm stubble in ODF and FAJ (45 cm). Tiller density was influenced by stubble height only in 1982 and 1983 when density for the 15 cm stubble averaged 111/m2 vs. 142/m2 for the 30-cm stubble. Tiller density in 1980, 1982, and 1983 was less (P<0.05) in JAO and YL treatments (109/m2) than in ODF and FAJ (167/m2). Forage dry matter yield in 1979-80 and 1982-83 depended on stubble height and seasons. Average yield at 15-cm height was greater for the FAJ treatment (1,700 kg/ha), similar for JAO (910 kg/ha) and ODF (910 kg/ha) and lowest for YL (660 kg/ha), but yield was similar at all seasons (510 kg/ha) at 30-cm stubble. Crude protein and IVOMD were influenced more by grazing time within a season than by seasons or stubble height. Poorest quality forage was at the beginning of the seasons (especially ODF and FAJ treatments). Best quality came from regrowth. Winter or spring grazing resulted in better stands of creeping bluestem than summer or year-long grazing.