6种热带亚热带豆科牧草抗寒性及营养品质比较

Comparison of cold resistance and nutritional quality of six tropical and subtropical leguminous forages during overwintering period

为了筛选华南地区适宜的优质冬季青饲料草种,本研究比较了旋扭山绿豆(Desmodium intortum)、大叶山蚂蟥(Desmodium laxiflorum)、异果山绿豆(Desmodium heterocarpum)、显脉山绿豆(Desmodium reticulatum)、糙毛假地豆(Desmodium heterocarpum var.strigosum)和柱花草(Stylosanthes guianensis)6种热带亚热带豆科牧草在广州越冬期的抗寒性及营养品质。结果表明,除柱花草外,其它5种豆科牧草均能保持青绿越冬,其中旋扭山绿豆和大叶山蚂蟥的叶绿素含量均显著高于其它牧草(P<0.05)。旋扭山绿豆的净光合速率最高(P<0.05),其次是大叶山蚂蟥(P<0.05),因此这两种牧草具有相对较强的抗寒性;与其它牧草相比,旋扭山绿豆在冬季能保持较高的粗蛋白含量(15.99%~20.26%)(P<0.05)以及较低的洗涤纤维(NDF 27.92%~30.89%、ADF 23.96%~27.06%)和缩合单宁含量(6.05~11.95mg·g^(-1))(P<0.05),因而具有较高的营养价值。因此,旋扭山绿豆可以作为华南地区冬季豆科青饲料的潜在优选草种。

To select suitable high quality green forage for winter season in Southern China, the cold resistance and nutritional qualities of six tropical and subtropical leguminous forage species including Desmodium intortum, D. laxi florum, D. heterocarpum, D. reticulatum, D. heterocarpum var. strigosum and Stylosanthes guianensis grown in Guangzhou during the overwintering period were compared. The results showed that all species could maintain green leaves in winter except S. guianensis, and the chlorophyll contents of D. intortum and D. laxiflorum were significantly higher than those of the other four species （P〈0.05）. Further, D. intorturn had the highest net photosynthetic rate （P〈0.05）, followed by D. laxiflorum. Hence, these two forages were considered to have a stronger cold resistance than others. During winter season, compared with the other species, D. intortum had a higher nutritional value because of its higher crude protein content （15. 99%- 20.26%） （P〈0.05） and lower detergent fiber （neutral detergent fiber, NDF： 27.92%-30.89%, acid detergent fiber, ADF. 23.96%-27.06%） and condensed tannin content （6.05-11.95 mg·g^-1） （P〈0.05）. Therefore, in Southern China, D. intortum can potentially be used as a preferred leguminous green fodder in winter.