EFFECTS OF NITROGEN ADDITION ON SOIL NUTRIENTS AND STOICHIOMETRY IN THE DESERT STEPPE OF NORTHERN CHINA

Desert grasslands are a vital part of Inner Mongolia's ecosystem but are increasingly degraded by adverse weather and human activities.The effects of fertilization on soil nutrients and stoichiometry in desert steppe were studied in order to screen out the optimal combination of forage fertilization concentration in this area, and provide theoretical basis for the improvement of degraded grassland in this area.This study focused on the Short-flowered Stipa Desert Grassland.Using a randomized block design, four treatments were applied: control, low-concentration nitrogen fertilization, medium-concentration nitrogen fertilization, and high-concentration nitrogen fertilization.The aim was to study the effects of fertilizer application on soil nutrients and stoichiometry.The results showed that: (1) low-concentration nitrogen fertilization (75 kg/ha) increased soil total carbon and total nitrogen content, while higher lowconcentration nitrogen fertilization (225 kg/ha) increased soil available potassium content; (2) changes in soil stoichiometry were primarily influenced by soil total carbon and total phosphorus.Moderate fertilization could increase soil nutrients content, but might lead to an imbalance in soil carbon and nitrogen ratio.The impact of different fertilization methods on soil carbon and nitrogen varies, and it was necessary to choose the appropriate fertilization method based on the actual situation of desert grasslands.In our study, the effectiveness of precipitation appears to be greater than the fertilization effect, resulting in poor soil nitrogen uptake and utilization, which will be a consideration in future research.