基于双稳定同位素和MixSIAR模型的冬小麦根系吸水来源研究

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 基于双稳定同位素和MixSIAR模型的冬小麦根系吸水来源研究 DOI: 10.5846/stxb201802250384 作者: 作者单位: 中国地质大学(北京),中国科学院地理科学与资源研究所,中国地质大学(北京),中国地质大学(北京),中国水利水电科学研究院,中国地质大学(北京),中国科学院生态环境研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41671027，41730749） Applying dual stable isotopes and a MixSIAR model to determine root water uptake of winter wheat Author: Affiliation: School of Water Resources and Environment,China University of Geosciences Beijing,Key Laboratory of Water Cycle and Related Land Surface Processes,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,School of Water Resources and Environment,China University of Geosciences Beijing,School of Water Resources and Environment,China University of Geosciences Beijing,State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,School of Water Resources and Environment,China University of Geosciences Beijing,State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:灌溉和施肥措施对农田水文循环具有重要影响，根系吸水是联系植物蒸腾和土壤水分运动的关键水文过程，定量识别灌溉施肥影响下作物根系吸水来源对农业用水优化管理具有重要意义。氘氧稳定同位素（D和18O）是追溯农田水分运移过程的理想天然示踪剂。基于2013-2015年北京市典型农田不同灌溉施肥处理冬小麦水分运移试验，利用D和18O双稳定同位素和MixSIAR贝叶斯混合模型，量化冬小麦主要根系吸水深度及其贡献比例，阐明作物水分来源的季节变化及不同处理间的差异，分析根系吸水与土壤水分分布变化的相互关系。研究结果表明：两季冬小麦返青-拔节、拔节-抽穗、抽穗-灌浆和灌浆-收获期主要根系吸水深度均值分别为0-20 cm（67.0%）、20-70 cm（42.0%）、0-20 cm（38.7%）和20-70 cm（34.9%），但季节变化差异显著，2014季主要吸水深度随作物的生长发育而逐渐增加，2015季则主要集中于浅层土壤（0-70 cm）。返青-抽穗期仅灌水20 mm或施肥105 kg/hm2 N促使拔节-抽穗期深层（70-200 cm）土壤水分利用率平均增加29%，而前期充分灌水且大量施肥（≥当地施肥量210 kg hm-2 N）时拔节-抽穗期根系吸水深度为土壤表层0-20 cm。在干旱少雨的冬小麦生长季内作物吸水来源与土壤水分消耗变化基本一致。 Abstract:Irrigation and fertilization scheduling significantly affect field water cycles. Root water uptake is the critical process that connects plant transpiration and soil water movements. It is necessary to quantify the crop water uptake sources under different irrigation and fertilization treatments for optimizing agricultural water management. The stable water isotopes of D and 18O are considered as ideal (natural) tracers for tracking water through the soil based on distinct isotopic signatures of water fluxes. The MixSIAR framework is the latest Bayesian stable isotope analysis mixing model in R that considers multiple sources of uncertainty and provides definite proportions of source contributions. In this study, dual stable isotopes of soil water and stem water were applied to determine seasonal water uptake patterns of winter wheat under different irrigation and fertilization treatments during 2013-2015 in Beijing, China. The contributions of the soil water at each depth to water uptake were quantified using the MixSIAR Bayesian mixing model. The direct inference method was also used to detect the potential root water uptake depth. Correlations between the water uptake patterns and soil moisture changes were further evaluated. The average contribution of soil water in the 0-20, 20-70, 70-150, and 150-200 cm layers was 35.6%, 27.6%, 23.1%, and 13.7%, respectively. The primary root water uptake depth was 0-20 cm (67.0%), 20-70 cm (42.0%), 0-20 cm (38.7%), and 20-70 cm (34.9%) during the greening-jointing, jointing-heading, heading-filling, and filling-harvest periods, respectively. Significant differences in crop water use appeared between the 2014 and 2015 growing seasons. The main root water uptake depth gradually increased from 0-20 cm (greening-jointing period) to 70-150 cm (heading-filling period) and was maintained at the 70-150 cm depth until the filling-harvest period in the 2014 season. However, winter wheat mainly took up soil water from the shallow layers (0-70 cm) over the 2015 season. In particular, the proportional soil water contribution in the 0-20 cm layer was remarkably higher (13.9%) than that in the 2014 season. Root water uptake patterns with soil moisture distributions were significantly influenced by different irrigation and fertilization treatments, especially in dry seasons. The main water uptake source was the soil water in the top layer (0-20 cm) under the T4 and T5 treatments during the jointing-heading period in 2015, because the root growth in the surface layer was stimulated by sufficient irrigation (80 mm) and abundant fertilization (≥ 210 kg/hm2 N) at early growth stages. Nitrogen deficiency with < 105 kg/hm2 N (T3) or less irrigation with 20 mm (T1 and T2) during the greening-jointing period promoted root growth in the deep soil layer (70-200 cm) and increased water adsorption by a mean of 29% during the jointing-filling period. Seasonal variations in the quantitative contribution of soil water at different depths were closely related to the soil moisture distributions. The large contribution of soil water in the 0-150 cm layer (86.3%) was consistent with its proportional consumption in soil water storage (92%) throughout the greening to harvest season of winter wheat. This study provides a simple and effective method for identifying crop water sources. The findings are of great significance for future fertilization and irrigation management. 参考文献 相似文献 引证文献