Abstract: Productive performance including the plant height, above-ground biomass per unit area, tillers per unit area, fertile tillers per unit area, shoot/leaf and fresh/dry matter weight ratios were determined and the distribution characteristics of root systems in 0~100 cm soil layers with 10 cm interval for 4 forage legumes species of Medicago sativa, Onobrychis viciifolia, Lotus corniculatus and Galega officinalis were studied. Results showed that the sequence of average above-ground fresh biomass (4 a and 5 a) in one cutting for 4 forage legumes species was as follow: L. corniculatus>M. sativa>O. viciifolia>G. officinalis. The sequence of average plant height in two years was O. viciifolia>M. sativa>G. officinalis>L. corniculatus. Tillers per square meter in two years for 4 forage legume species were M. sativa>L.corniculatus>O.viciifolia>G. officinalis. Fertile tillers per square meter in two years were O. viciifolia>M. sativa>L. corniculatus>G. officinalis. Average shoot/leaf ratios in two years were G. officinalis>M. sativa>O. viciifolia>L. corniculatus. Average moisture contents in two years for 4 forage legume species were G. officinalis>L. corniculatus>M. sativa=O. viciifolia. The distribution characteristics of root systems in 0~100 cm soil layers for 4 forage legumes species were as follow: the root weights of alfalfa in 0~40 cm soil layers accounted for about 98.3% of total, that of O. viciifolia in 0~ 30 cm soil layers was 85.8%, that of L. corniculatus in 0~10 cm soil layers was 80%, that of G. officinalis in 0~40 cm soil layers was 81.4%. These results suggested that L. corniculatus was suited to plant in slighter degraded pasture for water and soil erosion control in the early stage, G. officinalis with strong lateral roots was adapted to degraded grassland in the Losses Plateau which soil nutrient was poor, while O. viciifolia and M. sativa with potentially strong main root were fit for water and soil conservation in the Losses Plateau for a long time.

Key words: The Loess Plateau, Forage legumes, Biomass, Productive performance, Root systems, Soil conservation

摘要： 2007-2008年在庆阳黄土高原试验站连续2年观测了紫花苜蓿(Medicago sativa)、红豆草(Onobrychis viciaefolia)、百脉根(Lotus corniculatus)和东方山羊豆(Galega officinalis)4种豆科牧草地上部分生物量、株高、冠幅、单位面积枝条数、单位面积生殖枝数、茎叶比及干鲜比等生产性能,并分层研究其根系发育分布特征。结果表明:花期4种豆科牧草2年平均(4和5龄)单茬单位面积生物量为百脉根>紫花苜蓿>红豆草>东方山羊豆,2年平均株高为红豆草>紫花苜蓿>东方山羊豆>百脉根,单位面积枝条数为紫花苜蓿>百脉根>红豆草>东方山羊豆;单位面积生殖枝数为红豆草>紫花苜蓿>百脉根>东方山羊豆,茎叶比为东方山羊豆>紫花苜蓿>红豆草>百脉根,4种豆科牧草初花期平均含水量为东方山羊豆>百脉根>紫花苜蓿=红豆草。 2008年与2007年相比,除茎叶比和含水量外,其他生物学指标均不同程度降低;4种豆科牧草根系分布范围5龄较4龄萎缩幅度较大,5龄紫花苜蓿0~40 cm土层内的根系占98.3%,红豆草0~30 cm土层内的根系占85.8%,百脉根0~10 cm土层内的根系占80%,东方山羊豆0~40 cm土层内的根系占81.4%。百脉根适合于退化草地短期恢复改良,提供大量优质牧草;东方山羊豆叶量丰富,根系发达适宜于贫瘠地的中长期改造;而紫花苜蓿和红豆草根深草密,适宜于严重退化草地的长期水土保持改良利用。

关键词: 黄土高原, 豆科牧草, 生物量, 生产性能, 根系, 水土保持