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Acta Prataculturae Sinica ›› 2015, Vol. 24 ›› Issue (10): 166-174.DOI: 10.11686/cyxb2014492

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Biological characteristics and nutrients of the photoperiod-sensitive Sorghum×Sudangrass varieties in the arid land of east Gansu

HE Zhen-Fu, HE Chun-Gui*, WEI Yu-Ming, LIU Long-Sheng   

  1. Animal Husbandry-Pasture and Green Agriculture Institute, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China
  • Online:2015-10-20 Published:2015-10-20

Abstract: We studied the biological characteristics, the change in nutritional value at different growth stages and the impact of cutting frequency on production with three photoperiod-sensitive Sorghum×Sudangrass varieties: Monster, Big Kahuna and BJ0603 in the arid land of east Gansu. All varieties were sown in late April and were at the heading or flowering stage when harvested in early October. Hence the reproductive growth stage was not completed. At harvest, the differences in plant height, node number, leaf number and stem diameter among varieties were not significant, but the differences in the weight of leaf and single stem (stalk and leaves) were significant. The standardised grass yield (65% moisture content) and the dry matter production under one cut in one year were higher than those under two cuts, but not significantly different, while the fresh grass production under two cuts was significantly higher. The differences in the fresh grass production, the standardised grass yield and the dry matter production were significant among varieties whether under one or two cuts, with the yield ranking: Monster>BJ0603>Big Kahuna. From the early jointing stage to the booting stage, the levels of crude protein (CP) and ether extract (EE) in the stem decreased, while the acid detergent fiber (ADF) and neutral detergent fiber (NDF) values increased. The crude fiber (CF) and soluble sugar levels increased and then decreased, while the crude ash content (ASH) dropped sharply and the nitrogen free extract (NFE) values first decreased and then increased. The contents of CP, ADF, NDF, ASH, NFE and soluble sugar differed significantly among varieties, while no significant difference in EE and CF content was observed. Based on the variation in yield and nutrient content, the best utilisation strategy for photoperiod-sensitive Sorghum×Sudangrass was to cut once per year as silage and to harvest before the first frost. If utilized as hay or green chop, the best strategy in the arid land of east Gansu would be to cut twice yearly with the first cut performed between the late jointing stage and the booting stage, and the second cut before the first frost.