关键词: 水稻, 干物质积累, 养分积累, 养分平衡

Abstract: An investigation was conducted on the Artemisia giraldii population pattern and the niche breadth and niche overlap of A. giraldii in A. giraldii  communities in Erdos loess hilly and gully region, Inner Mongolia. With the restorative succession after field abandonment, the spatial pattern of A. giraldii population on ridge top changed initially from random to clumped in small scale, and then, to clumped at large scale. Accompanying with this change, the open patch area of A. giraldii  population increased significantly, with a simultaneous decrease of the population occupied area. The A. giraldii  population in gullies presented a typical random distribution, with its open patch area significantly smaller while its occupied area significantly larger, as compared to all the populations in A. giraldii communities on ridge top. Along the habitat gradient from hill ridge top to gully, A. giraldii  had the widest ecological niche, indicating its stronger capability in utilizing natural resources and its stronger adaptability to the environment, being able to widely distribute in various kinds of habitat in the loess hilly and gully region. A. giraldii  had a significant niche overlap with the other species dominant in the A. giraldii communities at the early stages of succession, and appeared earlier in the succession series, indicating that A. giraldii  was a dominant species at the beginning of the succession.

Key words: Rice, Dry matter accumulation, Nutrient accumulation, Nutrient balance