盐碱地人工草地土壤固氮作用强度的研究
Study on the intensity of Soil Nitrogen Fixation in the Artificial Meadow in Saline Lands
桤木人工林结瘤固氮的时空变化及其对后续植物的效应(Ⅱ)
Time-space variation of nodulation and nitrogen fixation in alder plantation and its after-effect on plant growth (ⅱ)