关键词: 禾草, 生活型, 发芽率, 杂草, 干扰

Abstract: Taking four vegetation restoration types, including abandoned land, Hippophae rhamnoides shrub, Larix principis-rupprechtii plantation, and mixed forest (mainly consisted of L. principis-rupprechtii, Betula platyphylla, Populus davidiana), in Guandi Mountain as test objects, this paper studied the seasonal variations of soil organic carbon, total nitrogen, NO^-₃-N, NH⁺₄-N, and of the quantities of soil microbes relating to nitrogen metabolism (bacteria, actinomycetes, fungi, N-fixing bacteria, nitrifiers, and denitrifiers). In the four vegetation restoration types, an obvious seasonal variation was observed in the soil inorganic N content and microbial quantity, and the soil organic carbon, total nitrogen, NO^-₃-N, NH⁺₄-N, and microbial population were decreased significantly with increasing soil depth. Compared with abandoned land, the soil organic carbon, total nitrogen, NO^-₃-N, NH⁺₄-N, and microbial population in H. rhamnoides shrub, L. principis-rupprechtii plantation, and mixed forest were all higher, with the highest values in mixed forest, in which, soil carbon and nitrogen, and soil microbial population increased by 0.21%-2.05% and 0.09%-19.25%, respectively, soil fungi increased up to 19.25%, and soil inorganic nitrogen increased by 0.01%-0.49%. There were significant positive linear relationships between soil organic carbon, total N, NO^-₃-N, and NH⁺₄-N and soil microbial population. In sum, vegetation restoration improved soil fertility, and the effect was most significant in mixed forest.

Key words: Grass, Life form, Germination rates, Ruderals, Disturbance