Dynamics of vegetation in arid areas have drawn worldwide attention. The expansion of irrigated cropland (ICE) in arid regions contributes to increased food security and impacts on the extent and development of regional vegetation. However, the quantitative attribution of vegetation growth variation from ICE and biogeochemical factors (e.g., atmospheric CO₂ concentration, climatic factors) is still lacking. Here, we assessed key drivers of vegetation growth in the inland arid region of Northwest China (IANC) from 1982 to 2018, including ICE, increased nitrogen rates, elevated atmospheric CO₂ concentration (eCO₂) and climate drivers, using normalized difference vegetation index (NDVI) and ecosystem gross primary productivity (GPP) as measures. These variables were quantified through trend decomposition, machine learning algorithms, and a satellite-based model. The results show that vegetation growth was increased in IANC mainly due to eCO₂ and ICE. After 1995, as the regional climatic aridity intensified, the CO₂ fertilization effect on vegetation growth decreased, as the atmospheric CO₂ concentration continued to increase. Meanwhile, irrigated cropland area increased sharply, and ICE-driven GPP variation exceeded that driven by eCO₂ in the whole region, while the ICE-driven NDVI variation exceeded that due to eCO₂ when the ICE reached 6.38%. The ICE effect on regional vegetation growth rather than the CO₂ fertilization effect has mitigated the slowdown of the rate of vegetation growth caused by climate changes. Although the ICE is conducive to food security and continuous greening of arid areas, further reclamation will exacerbate water scarcity. Our results provide research base for identifying the scale of sustainable agricultural development.

干旱地区植被动态已引起全世界的关注。干旱地区灌溉农田（ICE）的扩大有助于提高粮食安全并对区域植被的范围和发展产生影响。_{然而，ICE和生物地球化学因素（例如大气CO 2}浓度、气候因素）对植被生长变化的定量归因仍然缺乏。在这里，我们利用归一化植被指数评估了1982年至2018年西北内陆干旱地区（IANC）植被生长的关键驱动因素，包括ICE、氮含量增加、大气CO 2_浓度（eCO ₂）升高和气候驱动因素。 （NDVI）和生态系统总初级生产力（GPP）作为衡量标准。这些变量通过趋势分解、机器学习算法和基于卫星的模型进行量化。结果表明，IANC 植被生长的增加主要归功于 eCO ₂和 ICE。1995年以后，随着区域气候干旱加剧，CO ₂施肥对植被生长的作用减弱，大气CO ₂浓度持续升高。与此同时，灌溉耕地面积急剧增加，ICE驱动的GPP变化在整个区域超过了eCO _{2驱动的变化，而ICE驱动的NDVI变化超过了eCO 2}驱动的变化，当ICE达到6.38%时。ICE对区域植被生长的影响而非CO ₂施肥效应缓解了气候变化造成的植被生长速度的减慢。虽然ICE有利于粮食安全和干旱地区的持续绿化，但进一步围垦将加剧水资源短缺。我们的研究结果为确定农业可持续发展规模提供了研究基础。