补播禾草对退化苜蓿草地生产性能及牧草品质的影响

针对宁夏半干旱区7龄以上苜蓿(Medicago sativa)草地退化导致的牧草产量低、品质差等问题，本试验采用单因素随机区组设计，研究了多年生黑麦草(Lolium perenne)、披碱草(Elymus nutans)、苇状羊茅(Festuca arundinacea)、无芒雀麦(Bromus inermis)、鸭茅(Dactylis glomerata)补播对退化草地苜蓿主要农艺性状和牧草品质的影响，并利用主成分分析方法(PCA)评价其改良效果。结果表明：补播禾草对苜蓿株高、叶茎比、一级分枝数和干草产量均有显著影响(P<0.05)，其中，补播苇状羊茅干草产量最高，其次为多年生黑麦草和无芒雀麦；补播禾草对牧草粗蛋白、粗脂肪、粗灰分、中性洗涤纤维和酸性洗涤纤维含量有显著影响(P<0.05)；PCA分析得出，补播鸭茅、苇状羊茅综合性状分别排第一、二位。因此，可根据不同改良目的选择不同禾草种类进行补播，苇状羊茅可显著提高退化苜蓿草地生产性能，补播鸭茅可显著改善退化苜蓿草地牧草品质。

Effects of Reseeding Grass on Production Performance and Forage Quality of Degraded Alfalfa Grassland

Aiming at the problems of low forage yield and poor quality of the 7-year degraded alfalfa grassland in the semi-arid area of Ningxia,the experiment adopted a single-factor random block design to study the effect of reseeding perennial black wheatgrass,lyme grass,tall fescue,awnless brome and orchard grass on the major agronomic traits and forage quality of degraded alfalfa grassland,and principal component analysis(PCA)was used to evaluate its improvement effect.The results showed that reseeding grasses had significant effects on alfalfa plant height,leaf-stem ratio,primary branch number and hay yield(P<0.05).Among them,reseeding tall fescue had the highest yield,perennial black wheatgrass and awnless brome followed.Reseeding grasses had significant effect on the content of crude protein,crude fat,crude ash,neutral detergent fiber and acid detergent fiber(P<0.05).According to PCA analysis,the comprehensive traits of reseeding orchardgrass and tall fescue ranked the first and the second,respectively.Therefore,different grass species could be selected according to different improvement purposes.Tall fescue could significantly improve the production performance of degraded alfalfa grassland,and reseeding orchard grass could significantly improve the forage quality of degraded alfalfa grassland.