关键词: 墨西哥玉米, 留茬高度, 刈割时期, 再生产量, 饲用品质, 再生系数

Abstract: A fieldplot experiment in 2002 and 2003 was conducted to study the effects on regrowth performances (including the yield and forage nutritive quality of the regrowth) of Zea mexicana cut at different clipping stages with different high stubbles. The plant height was regarded as the criteria to establish the clipping stage. The treatments cut at different stages with the same high stubble and cut at different stubble height with the same high plant. The approximate analysis method was utilized to evaluate the forage nutritive quality of the regrowth, and the conception of regrowth coefficient (RGC) was introduced to determine the regrowth performances of Zea mexicana in this experiment. The findings of the experiment demonstrated that the regrowth yield and gross energy (GE) yield of treatment Ⅱ clipped with 30 cm stubble and 95 cm plant were higher than the control (stubble height: 20 cm) and treatment Ⅰ(stubble height: 10 cm), reached 11.60 kg·m-2 (fresh weight) and 278 kJ·m-2，respectively. The crude protein content and nitrogen free extract content of the regrowth of treatment Ⅱ were higher，while the crude ashes content and acid detergent fiber content were reverse. The regrowth yield and GE yield of treatment Ⅳ clipped with 20 cm stubble and 130 cm plant had no significant difference to those of the control，and were significantly higher than those of treatment Ⅲ (plant height: 65 cm) in this experiment. The regrowth forage nutritive quality of treatment Ⅲ was the highest of the five treatments. According to the regrowth yield and forage quality，the treatment with RGC≈2.5 had the best regrowth performances，and the cutting mode with 30cm stubble and 95cm plant was able to make Zea mexicana be high yield and high quality.

Key words: Zea mexicana, Stubble height, Clipping stage, Regrowth yield, Forage quality, Regrowth coefficient