陇东苹果园土壤浸提液对黑麦草和紫花苜蓿种子萌发及幼苗生长的影响

Effect of soil extract from an apple orchard on ryegrass and alfalfa seed germination and seedling growth in eastern Gansu

果园生草是一种新型土壤管理模式,草地成功建植是该模式建立的基础。苹果园土壤的特异性可能影响草类种子萌发及幼苗生长,从而影响草地建植。本研究分析了陇东苹果园不同土层的土壤浸提液对黑麦草(Lolium perenne)和紫花苜蓿(Medicago sativa)种子萌发及幼苗生长的影响,结果表明,苹果园土壤浸提液提高了黑麦草种子萌发数,但减小了紫花苜蓿种子萌发数,但对二者种子萌发率没有影响;与无落叶相比,落叶残留时土壤浸提液加快了种子萌发,并有提高种子萌发率的趋势。土壤浸提液抑制了黑麦草和紫花苜蓿幼苗胚根的生长,减少了幼苗单株鲜重;但有落叶残留时的土壤浸提液相对于无落叶的土壤浸提液处理减小了对黑麦草和紫花苜蓿幼苗胚根生长的抑制作用。因此,苹果园土壤可通过抑制草类植物幼苗生长而非种子萌发来影响草地建植;从幼苗生长受抑制程度来看,苹果园生草选择黑麦草等禾本科牧草更适合。

Inclusion of grass into fruit-tree orchards,is a new strategy of soil management. Successful grassland establishment is essential for the construction of this model. However,the specificity of soils in apple orchards may affect grass seed germination and seedling growth; thereby,affecting grassland establishment. The effect of soil extract on ryegrass( Lolium perenne) and alfalfa( Medicago sativa) seed germination and seedling growth was studied in an apple orchard. Soil extract increased the number of germinated ryegrass seeds,but decreased the number of germinated alfalfa seeds. There was no effect of soil extract on seed germination rate of either species. Compared with no leaves remaining on the soil,extract from the soil with leaves accelerated the germination of the two grassseeds and tended to increase the germination rate. The soil extract from the apple orchard inhibited root growth and reduced seedling fresh weight of ryegrass and alfalfa seedlings. The root growth of alfalfa and ryegrass was inhibited by the falling leaves remaining on the soil. Therefore,in apple orchards,the effect of the soil on grassland development may be attributed mainly to the inhibition of seedling growth of grass species,rather than to the inhibition of seed germination. Falling leaves from apple trees may enhance such inhibition. Compared with the herbaceous species,the leguminous species was more susceptible to the inhibition observed.