With ongoing global climate change and human activities, increasing desertification plays a predominant role in increasing soil nutrient losses. Soil nitrogen (N) is the essential limiting nutrient supporting plant growth and evaluating soil nutrient content, especially in desert ecosystems. N microbial processes will ultimately restore and maintain the balance in the soil N cycle, but the damage caused by desertification to soil N functional microorganisms associated with N supply, transformation, and loss is poorly understood. We examined changes in soil N and N functional gene (NFG) abundances within vertical profiles (i.e., soil depths of 0–100 cm) throughout the desertification process. We found that the abundance of N functional genes (NFGs) (except the N-fixation gene) decreased during the desertification process, almost all NFGs were attenuated along the vertical profiles, and available phosphorus (AP), soil water content (SWC) and pH were the best explanatory variables. The sums of (AOA + AOB) (associated with available N transformation) and (nirK + nirS + qnorB + nosZ) (associated with N loss) significantly decreased as desertification progressed, leading to decreased N transformation and loss potential. The (nifH + chiA) associated with available N supply increased along the desertification process gradient, suggesting enhanced potential for the acquisition available N. The increased ratio of (nifH + chiA + AOA + AOB)/(nirK + nirS + qnorB + nosZ) (associated with available N storage) collaboratively contributed to enhanced available N storage potential throughout the desertification process. Our results lay the foundation for better understanding the distinct responses of NFGs to desertification and the process through which they ultimately regulate available N storage in the degraded soils of desert ecosystems.

随着全球气候变化和人类活动的持续进行，沙漠化的加剧在增加土壤养分流失方面起着主要作用。土壤氮是支持植物生长和评估土壤养分含量的必要限制养分，尤其是在沙漠生态系统中。N微生物过程最终将恢复并维持土壤N循环中的平衡，但是人们对由荒漠化引起的与N供应，转化和损失相关的土壤N功能微生物的损害知之甚少。我们研究了整个荒漠化过程中垂直剖面（即土壤深度为0–100 cm）内土壤N和N功能基因（NFG）丰度的变化。我们发现，在荒漠化过程中，N功能基因（NFG）的丰度（N固定基因除外）减少了，几乎所有的NFG都沿垂直剖面衰减，而有效磷（AP），土壤水分（SWC）和pH是最好的解释变量。（的总和随着荒漠化的进行，AOA  +  AOB）（与可用的N转化相关）和（nirK  +  nirS  +  qnorB  +  nosZ）（与N损失相关）显着降低，从而导致N转化和损失潜力降低。与可用氮供应相关的（nifH  +  chiA）沿荒漠化过程梯度增加，表明获得可用氮的潜力增加。（nifH  +  chiA  +  AOA  +  AOB）/（nirK  +  nirS  +  qnorB  + nosZ）（与可用的N储存量相关）在整个荒漠化过程中共同促进了可用N储存量的增加。我们的结果为更好地了解NFG对沙漠化的不同反应以及它们最终调节沙漠生态系统退化土壤中的可用氮存储量的过程奠定了基础。