留茬高度对苜蓿再生干草质量及返青率的影响

Effect of stubble height on the hay quality of regenerated alfalfa and the reviving rate

为了解决生产中由于留茬高度不当造成苜蓿再生干草产量、品质及翌年返青率较低的问题，试验选择“金皇后”紫花苜蓿，测定分析不同留茬高度处理对苜蓿再生千草产量、品质及翌年返青率的影响，以确定最适留茬高度。结果表明：随着留茬高度的增加，苜蓿干草产量呈降低趋势；留茬≥8～〈11cm时，苜蓿再生干草粗蛋白含量、相对饲用价值较高，分别为20．79％、147．24％，其次为留茬≥5-〈8cm，两者间粗蛋白含量、相对饲用价值差异不显著（P〉0．05）；留茬≥8～〈11cm时，苜蓿根内可溶性糖含量为89．41mg／g，翌年返青率为79．89％，显著高于其他处理（P〈0．05）。说明凌海地区第一、二、三茬苜蓿以留茬高度I〉5～〈8em为宜，但第四茬苜蓿应留茬≥8-〈11cm。

To solve the problem of low bay quality of regenerated alfalfa and low reviving rate in the following year due to unsuitable stubble height in production, ＂ Gold Queen ＂ alfalfa was selected in the test. The effects of different treatments of stubble heights on the hay yield and quality of regenerated alfalfa as well as the reviving rate in the following year were determined and analyzed to determine the optimal stubble height. The results showed that the yield of alfalfa hay was decreased with the increase of stubble heights. The regenerated alfalfa had higher crude protein content and relative feed value when the stubble height was greater than or equal to 8 cm to less than 11 cm, which were 20.79 % and 50.24 %, respectively, and there was no significant difference in the crude protein content and relative feed value （ P 〉 0.05 ） between them when the stubble height was greater than or equal to 5 cm to less than 8 cm. When the stubble height was 8 to 11 cm, the soluble sugar content in the roots of alfalfa was 89.41 mg/g, and the reviving rate in the following year was 79.89 %, which was significant higher （P 〉 0. 05 ） than other treatments for the stubble height. The results indicate that the stubble heights at greater than or equal to 5 cm to less than 8 cm is suitable for the first, second, and third stubble of alfalfa in Linghai area, and the stubble height for the fourth stubble of alfalfa should be greater than or equal to 8 cm to less than 11 cm.