Natural grasslands represent the second largest ecosystem in Turkey. However, the impact of varying nitrogen (N) fertilization rates on overall soil health indicators have not been reported in the country. A 2-year study was conducted in the Kahramnmaraş Plateau region in Turkey to evaluate the impacts of seven N application rates [i.e., 0 (N0), 50 (N50), 100 (N100), 150 (N150), 200 (N200), 250 (N250), and 350 (N350) kg N ha⁻¹] on physical, chemical, and biological parameters of soil health. Nitrogen addition decreased bulk density by 8–12%, and increased aggregate stability by 3–5% and EC up to 110%. Application of ≥ 100 kg N ha⁻¹ increased soil porosity up to 6.7%. Soil pH and C:N ratios were not affected by N addition. The lowest plant available water occurred with the N0 and N50 treatments, decreasing around 24% and 17% compared to N300. Soil organic carbon, total nitrogen, and C and N stocks increased with increasing N addition. Application of N300 rates increased C stocks between 4 and 34%, and N stocks between 15 and 22% compared to all other treatments. Compared to control, N250 increased microbial biomass carbon by 349% and nitrogen by 250%. Microbial respiration in the N250 and the N300 treatments was 97% and 129% greater than control. Addition of N fertilization for a first time in a grassland ecosystem with a previous history of long-term overgrazing, even at low rates, positively impacted several parameters of soil health, a positive impact that could ensure a greater sustainability of these fragil systems over the long-term.

天然草原是土耳其第二大生态系统。但是，该国尚未报告氮肥施用量变化对总体土壤健康指标的影响。在土耳其的Kahramnmaraş高原地区进行了为期2年的研究，以评估7种氮肥施用量的影响[即0（N0），50（N50），100（N100），150（N150），200（N200） ，250（N250）和350（N350）kg N ha ^-1 ]关于土壤健康的物理，化学和生物学参数。氮的添加使堆积密度降低了8–12％，骨料稳定性提高了3–5％，EC最高提高了110％。施用≥100 kg N ha ^-1增加土壤孔隙率达6.7％。土壤pH和C：N比不受氮添加的影响。N0和N50处理的植物可用水最低，与N300相比分别减少了约24％和17％。土壤有机碳，总氮，碳和氮储量随氮添加量的增加而增加。与所有其他处理相比，使用N300比率可使C储量提高4％至34％，将N储量提高15％至22％。与对照相比，N250使微生物生物量碳增加了349％，氮增加了250％。N250和N300处理的微生物呼吸量比对照分别高97％和129％。在曾经长期放牧的草原生态系统中，即使是低速放牧，也首次添加了氮肥，对土壤健康的几个参数产生了积极影响，