一、前言红豆草(Onobrychis viciifolia Scop.)于1944年引入我国,其抗旱能力较强,饲用价值较高,而且迄今为止还未发现有含任何对家畜有害的化学成份。因此,红豆草是我国北方干旱和半干旱地区很有发展前途的一种多年生豆科牧草。豆科牧草的根瘤与根瘤菌共生能固定大气中的氮素。一般来说,共生固氮能基本满足豆科牧草对氮素的要求,施氮肥增产效果 I. Introduction Onobrychis viciifolia Scop. Was introduced into our country in 1944 and has strong drought resistance and high fodder value, and so far no chemical components harmful to livestock have been found. Therefore, sainfoin is a perennial leguminous pasture that is promising in arid and semi-arid areas of northern China. Leguminous nodules and rhizobium symbiosis can fix atmospheric nitrogen. In general, symbiotic nitrogen fixation can basically meet the leguminous forage nitrogen requirements, nitrogen fertilizer yield