Effects on plant biomass and CNP contents of plants in grazed andfenced steppe grasslands of the Loess Plateau

Abstract

Abstract: The plant subsystem in typical steppe grassland of the Loess Plateau was divided into four components: live shoots, standing dead matter, litter, and underground roots. The plant biomass of these four components and their C, N, and P contents were studied in grazed (GG) and fenced (FG) grasslands. The seasonal dynamics of each component biomass was correlated with their C, N and P contents both in grazed and fenced grasslands. There were significant positive correlations between plant biomass and C, N, and P contents, with correlation coefficients of 0.990, 0.899, 0.936 (FG) and 0.990, 0.891, 0.936 (GG), respectively. The differences in C, N, and P contents of each plant component were caused by the difference in plant biomass. The total biomass, aboveground and underground biomass, standing dead matter and litter, and their C, N, and P contents were significantly (P<0.05) higher in fenced grassland than those in grazed grassland. The N and P contents in live shoots were highest in July, and significantly (P<0.05) lower in fenced (1.291 8 and 0.083 7 g/m² for N and P respectively) than in grazed (1.529 7 and 0.100 2 g/m² for N and P respectively) grassland. The results indicate that the higher plant N, P storages in grazed grassland were mainly attributed to the increases of young organ biomass and their N, P contents, which further improve the utilization of grassland.

CLC Number:

S812.8

DONG Xiao-yu, FU Hua, LI Xu-dong, NIU De-cao, GUO Ding, LI Xiao-dong. Effects on plant biomass and CNP contents of plants in grazed andfenced steppe grasslands of the Loess Plateau[J]. Acta Prataculturae Sinica, 2010, 19(2): 175-182.

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