College of Resources and Environmental Engineering, Ludong University, Yantai 264025, China; Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling 712100, China.
College of Resources and Environmental Engineering, Ludong University, Yantai 264025, China.
Sci Total Environ. 2024 Jun 15;929:172228. doi: 10.1016/j.scitotenv.2024.172228. Epub 2024 Apr 9.
Deep soil water (DSW) plays a pivotal role in tree growth, susceptibility to drought-induced mortality, and belowground carbon and nutrient cycling. Assessing DSW depletion is essential for evaluating the resilience and sustainability of planted forests. But, due to the poor accessibility of deep soil layers, little is known about large scale DSW depletion. In this study, we leverage the concept that "plants are reliable indicators of deep soil water" to estimate DSW depletion in planted forests within the arid and semi-arid regions of the Chinese Loess Plateau (CLP). Our approach involves establishing a model that correlates forest age with DSW depletion. We then employ this model to estimate DSW depletion across the region, utilizing readily available data on the distribution of forest age and utilize the boundary models to consider the variability of DSW depletion estimated with forest age. Our results indicate that the model effectively estimates DSW depletion in planted forests, demonstrating a strong fit with an R of 0.71 and a low root mean square error (RMSE) of 332 mm. Notably, a substantial portion of the planted forest areas on the CLP has experienced DSW depletion from 800 mm to 1600 mm, and totaling 2.41 × 10 m DSW depletion from 1995 to 2020 based on the general model. However, the available DSW in the existing planted forests on the CLP is estimated at only 1.73 × 10 m by 2038. This suggests that there is potential risks and unsustainability for further afforestation efforts and carbon sequestration on the CLP under the current continuous afforestation measures. Our study holds significant implications for sustainable regional ecological management and quantifying water resources for carbon trading through afforestation.
深层土壤水（DSW）在树木生长、耐旱性和地下碳及养分循环中起着关键作用。评估 DSW 消耗对于评估种植林的恢复力和可持续性至关重要。但是，由于深层土壤层难以进入，对于大规模的 DSW 消耗知之甚少。在这项研究中，我们利用“植物是深层土壤水的可靠指标”这一概念，来估计中国黄土高原（CLP）干旱和半干旱地区种植林的 DSW 消耗。我们的方法涉及建立一个与森林年龄与 DSW 消耗相关的模型。然后，我们利用这个模型来估算整个地区的 DSW 消耗，利用现成的关于森林年龄分布的数据，并利用边界模型来考虑用森林年龄估算的 DSW 消耗的变异性。我们的研究结果表明，该模型可以有效地估算种植林的 DSW 消耗，与实际值的拟合度很强，R 值为 0.71，均方根误差（RMSE）低至 332mm。值得注意的是，在 CLP 的大部分种植林地区，DSW 已经从 800mm 到 1600mm 不等，根据通用模型，从 1995 年到 2020 年，总共消耗了 2.41×10^9m 的 DSW。然而，根据现有的种植林，预计到 2038 年 CLP 现有的种植林的可利用 DSW 仅为 1.73×10^9m。这表明在当前持续的造林措施下，CLP 进一步造林和碳固存存在潜在风险和不可持续性。我们的研究对于可持续的区域生态管理和通过造林来量化碳交易中的水资源具有重要意义。
