Abstract: The determination and analysis of the biomass of fine roots of Caragana intermedia plantations with 3, 5, 10, 16 and 30 tree-ages at the Qinghai Province Sand Control Experimental Station were carried out. The purposes of the study were to accurately understand the vertical distribution, dynamic variation and turnover rate of the biomass of fine roots of C. intermedia plantations. The results showed that about 41% living fine roots and 39% dead fine roots of C. intermedia plantations were distributed in soil layer 0-20 cm in depth, 38% living fine roots and dead fine roots were distributed in soil layer 20-40 cm in depth, and 21% living fine roots and 23% dead fine roots were distributed in soil layer 40-60 cm in depth. There was an obvious seasonal dynamic change of the biomass of fine roots, and the peak biomass of living fine roots appeared in June and August or June and September, and its maximum occurred in August or September; the peak biomass of dead fine roots appeared in August and September, and its maximum also occurred in August or September. The turnover rates of C. intermedia plantations with different tree-ages were 0.53, 0.66, 0.56, 0.73 and 0.78 times·a^-1. The biomass and turnover rate of fine roots of C. intermedia plantations increased with the increase of tree-age, but decreased with the increase of soil depth. 

Key words: alpine sandy land, Caragana intermedia Kuang et H. C. Fu; plantation, fine root biomass, fine root distribution, fine root turnover rate; Qinghai Province