School of Civil Engineering, Sun Yat-sen University, Guangzhou, China.
School of Civil Engineering, Sun Yat-sen University, Guangzhou, China.
Sci Total Environ. 2022 Jan 10;803:149810. doi: 10.1016/j.scitotenv.2021.149810. Epub 2021 Sep 1.
Two-way feedbacks exist between water-stressed vegetation and agricultural drought. Previous studies have focused mainly on the responses of vegetation to agricultural droughts but rarely on those of agricultural droughts to vegetation. Based on a new drought index (AgDI) that incorporates dynamic climatic and vegetation information, this study evaluated the impacts of climate and vegetation variabilities on agricultural droughts in 20 catchments in southwestern China, a region frequently hit by droughts. Results showed that the drought-stressed vegetation tended to alleviate agricultural droughts, and the drought-alleviating ability of vegetation was affected by vegetation types and the magnitudes of the changes in climate. Compared to other types of vegetation, the natural forest generally has a greater ability to affect agricultural drought. Overall, the relative contribution (mean of 29.9 ± 24.6%) of changes in vegetation to agricultural drought was at least comparable to those of the changes in potential evapotranspiration (mean of 14.4 ± 12.7%). Results also showed that even though vegetation has the ability to alleviate agricultural droughts, the changes in agricultural droughts were still dominated by climate changes, especially precipitation (mean relative contribution of 55.7 ± 24.2%).
水胁迫植被与农业干旱之间存在双向反馈。先前的研究主要集中在植被对农业干旱的响应上，但很少关注农业干旱对植被的响应。本研究基于一个新的干旱指数（AgDI），该指数综合了动态气候和植被信息，评估了气候和植被变异性对中国西南部 20 个流域农业干旱的影响，该地区经常遭受干旱。结果表明，受胁迫的植被往往会缓解农业干旱，而植被的缓解能力受植被类型和气候变化幅度的影响。与其他类型的植被相比，天然林通常具有更大的影响农业干旱的能力。总体而言，植被变化对农业干旱的相对贡献（平均值为 29.9±24.6%）至少与潜在蒸散变化（平均值为 14.4±12.7%）相当。结果还表明，尽管植被有能力缓解农业干旱，但农业干旱的变化仍主要受气候变化的影响，尤其是降水（平均值相对贡献为 55.7±24.2%）。
