关键词: 减量施N, 冬小麦-夏玉米种植体系, 硝态氮残留, N平衡

Abstract: The study on the germination characteristics of newly collected and one year-buried seeds of 65 plant species on Horqin semi-arid steppe showed that after one year’s burial, the seeds of 38 plant species still remained their vitality. For the species whose freshly collected seeds had a germination rate higher than 80%, the seed germination rate after burial was decreased, while it was in adverse for those whose freshly collected seeds had a germination rate less than 80%. The effects of burial on seed germination varied with the ecological types of the species (i . e . , weed, steppe species, meadow species, and psammophytes). After one year’s burial, the germination rate of perennials had no significant increase, but that of annuals increased significantly (P<0.05). The species with a <10% difference of germination rate between their freshly collected and one year-buried seeds could be classified into three categories, according to the seed germination pattern,i . e ., germination was promoted by burial (e . g .Artemisia halodendron), restrained by burial (e. g. A. sieversiana); and unchanged after burial (e.g. Lappula myosotis).

Key words: Reduction of N application, Wheat-maize cropping system, Residual nitrate N, N balance