Many studies have underscored the impacts of drought on ecosystems, and some researchers reported the effects of accumulated soil moisture deficit (ASMD) on light use efficiency (LUE) in grassland. However, the potential effects of ASMD on gross primary productivity (GPP) and LUE for both cropland and forest ecosystems are still not understood. This study elucidated the effects of accumulated and lagged soil moisture deficit (ASMD and LSMD, respectively) on GPP and LUE in these two ecosystems by using observations from 10 cropland and 25 forest flux sites during drought years. The results showed that the effects of ASMD and LSMD on LUE/GPP for both cropland and forests obviously surpass the concurrent effects (CSMD). For cropland, the mean R2 between CSMD/LSMD/ASMD with LUE were 0.22, 0.47, 0.56, respectively, and were 0.29, 0.54, 0.74 with GPP, respectively. For forest, the mean R2 between CSMD/LSMD/ASMD with LUE were 0.21, 0.36, 0.46, respectively, and were 0.34, 0.63, and 0.65 with GPP, respectively. Additionally, the effects of ASMD and LSMD on LUE are more pronounced for cropland than for forests, and for both cropland and forest, the effect of ASMD is stronger than that of LSMD. This study underscores the crucial role of ASMD in influencing LUE and GPP for cropland and forests, thereby offering a theoretical foundation for incorporating ASMD into LUE models to enhance the accuracy of GPP simulations, especially during drought periods.

中文翻译：

---

对于农田和森林，累积土壤水分亏缺对总初级生产力和光能利用效率的影响强于滞后土壤水分亏缺


许多研究强调了干旱对生态系统的影响，一些研究人员报告了累积土壤水分亏缺 （ASMD） 对草地光利用效率 （LUE） 的影响。然而，ASMD 对农田和森林生态系统的总初级生产力 （GPP） 和 LUE 的潜在影响仍不清楚。本研究通过使用干旱年份 10 个农田和 25 个森林通量站点的观测数据，阐明了累积和滞后土壤水分亏缺 （分别为 ASMD 和 LSMD） 对这两个生态系统中 GPP 和 LUE 的影响。结果表明，ASMD 和 LSMD 对农田和森林 LUE/GPP 的影响明显超过并发效应 （CSMD）。对于农田，CSMD/LSMD/ASMD 与 LUE 的平均 R2 分别为 0.22 、 0.47 、 0.56 和 GPP 的 0.29 、 0.54 、 0.74 。对于森林，CSMD/LSMD/ASMD 与 LUE 的平均 R2 分别为 0.21 、 0.36 、 0.46 和 GPP 分别为 0.34 、 0.63 和 0.65。此外，ASMD 和 LSMD 对 LUE 的影响对农田的影响比对森林更明显，并且对于农田和森林，ASMD 的影响都比 LSMD 强。本研究强调了 ASMD 在影响农田和森林 LUE 和 GPP 方面的关键作用，从而为将 ASMD 纳入 LUE 模型以提高 GPP 模拟的准确性提供了理论基础，尤其是在干旱时期。