不同施磷浓度对柱花草和黑籽雀稗根系分布的影响

Influences of different phosphorus concentrations on the root distribution of Stylosanthes and black seed Paspalum

采用根箱法,结合Winrhizo2004a根系扫描测定系统,以豆科牧草柱花草和禾本科牧草黑籽雀稗为试验材料,研究不同施磷水平对柱花草和黑籽雀稗根系分布的影响。结果表明,2种牧草根系分布随土壤深度的增加而减少,柱花草集中分布于0～10 cm土层,黑籽雀稗集中分布于0～20 cm土层;磷对2种牧草根系生长的影响存在较大的差异。低磷(P1,0.48 g P2O5/kg土)更适合柱花草根系和地上部分的生长,高磷(P3,1.92 g P2O5/kg土)水平对根系生长有抑制。黑籽雀稗对磷的需求量大,随着磷施入量的增加,根干重、总根长、根表面积、体积和根系平均直径均有所提高。

Using a root-boxing and root scanning measurement system,the leguminous forage grass,Stylosanthes and the Graminaceous forage grass black seed Paspalum,were used to study the effect of phosphorus concentration on root distribution.Root biomasses of grasses significantly decreased with soil depth.The roots of Stylosanthes were concentrated in the 0-10 cm layer and those of the black seed Paspalum in the 0-20 cm layer.The black seed Paspalum had a higher demand for phosphorus and responded more to added phosphorus.For Stylosanthes,a low concentration of phosphorus（0.48 g P2O5/kg soil） is more suitable for the root and aboveground growth than a high concentration（1.92 g P2O5/kg soil）.For the black seed Paspalum,an appropriate increase in the amount of phosphorus into the soil,can increase the root and aboveground dry weight,total root length,root surface area,volume and root average diameter.