Abstract: Soil moisture content is an important factor for the distribution of desert vegetation. Climate warmingwetting trend is becoming more obvious in west China in recent years. The increase of precipitation will inevitably affect the N isotope absorption of plants. In this paper, the response of plant N isotope to soil moisture content change in the labeled and unlabeled sample plots in the southern marginal zone of the Gurbantunggut Desert were studied using the ¹⁵N labeling method. The results are as follows: (1) The water increase treatment increased significantly the soil moisture regime and soil moisture content; (2) Ndff in plants in the study area varied in a range from 0.39 to 0.59, its highest value occurred in a treatment case of soil moisture content increased by 30%, and the lowest one was found in a treatment case of soil moisture content increased by 20%; (3) The plant Ndff was increased significantly after applying nitrogenous fertilizer, and it varied in a range of 15.27-31.24. From the perspective of different parts of plant, the proportion of nitrogen absorbed by plant was the highest in stems, and it was the lowest in roots.

Key words: stable N isotope, soil moisture content, precipitation increase, desert grassland, plant growth, Gurbantunggut Desert
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stable N isotope, soil moisture content, precipitation increase, desert grassland, plant growth, Gurbantunggut Desert
stable N isotope, soil moisture content, precipitation increase, desert grassland, plant growth, Gurbantunggut Desert
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stable N isotope, soil moisture content, precipitation increase, desert grassland, plant growth, Gurbantunggut Desert