Study On Turf Properties Of Wild Medicago Lupulina L.

Medicago lupulina L. (black medic), an annual or biennial wild species of Medicago, is widely distributed throughout China with abundant wild germplasm. It has a strong adaptability and tolerance to cold, drought, and poor soil and has rapid growth, as such had been grown as a green manure.Field exploration indicated that under wild conditions, black medic branches are creeping or semi-erective, so that they occupy and cover earth surface easily. It has verdant green leaves, less biomass, more seeds and unique character of seeding and dropping. Branches stretching, blooming, seeding, maturing and dropping can occur in one plant at the same time and last one to two months. After dropping, seeds are sowed naturally. These habits make it possible to regenerate itself. Seed has high rate hardness and lower natural germination but a strong vitality and can maintain fertility in soil for years.By using POD isoenzyme analysis, abundant ecotypes in GanSu can be divided into two groups: one is in Linxia and Pingliang, the other is in Qinan, Lanzhou, Zhuoni and Xunhua, which is an adjacent county in Qinghai province.Results of germination test on black medic at different time showed that: newly-matured with ample sunlight-dried seed had lower germination rate (about 9.1%) and no sensitive to temperature, otherwise, the rate of fresh without sunlight-dried seeds higher (about 34%). The rate rose up to 74.8% after scraping seed coat by sandpaper. All these results indicated that when seed was ripe, embryo also matured without post-mature stage. The main reason for lower germination rate was that hardness made seeds difficult to absorb water, the existence of seed coat restricting germination excluded the possibility of embryo post-mature.The results of density test indicated that when black medic turf was to build up, seed rate should be 10 to 20 g/m2, the higher seed rate, the poorer winter hardiness, before-winter irrigation, density, plant growth period, mowing might together affect over-wintering, thin sowing favored over-wintering. In the next spring, revival plant and new seedling appeared at same time in field. Reviving plants started to flower about one month after recovery during which new seedlings were 3 to 4cm. Sward height depended on turf density. Turf was verdant green with small and yellow flowers inlaying on the sward surface, but the winter hardiness exerted much influence on turf. The results of different sowing time test indicated that the suitable sowing time was before mid August, the later sowing time, the less biomass and poorer winter hardiness.The results of field exploration, laboratory analysis and field trial indicated that the habits of flowering, seed dropping and dormancy, sward self-regeneration and other traits of black medic made it suitable for turf and landscape establishment.