Study on the optimal harvest time of Secale cereale‘Ganyin No.1’ in cold regions of Tianzhu County

Determination of the best possible harvest time is important to ensure the optimal combination of grass yield and nutritional content. In this study, the optimal harvest time of Secale cereale ‘Ganyin No.1’ was determined by means of assessing plant height, fresh yield, stem-leaf ratio, fresh-dry ratio, crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF), at different growth stages, in the cold region of Tianzhu. The results showed that plant height, hay yield, and ADF, and NDF content increased in correlation with growth stages. Conversely, CP content increased during the first stages, but then decreased. Growth was fastest during the jointing and heading stage. No significant difference was observed between fresh yield at flowering stage, and at milky stage (P>0.05). Though the hay yield at flowering stage was less than that at milky stage, the content of CP was highest at flowering stage with up to 2.16 t·ha-1. Applying a subordinate function analysis method, the comprehensive evaluating value during the four cutting stages decreased from heading to flowering, to booting, and to milky stage. In conclusion, the timespan from heading to flowering stage seems to be the optimal harvest time.