引用本文:裴艳武,黄来明,邵明安,李荣磊,张应龙.毛乌素沙地东南缘人工林樟子松根系吸水来源与影响因素[J].土壤学报,DOI:10.11766/trxb202011060608,[已录用].
裴艳武,黄来明,邵明安,李荣磊,张应龙.Root Water Source of Pinus sylvestris L. var. Mongholica Litv. and Influencing Factors in the Southeastern Part of Mu Us Sandy Land, China[J].Acta Pedologica Sinica,DOI:10.11766/trxb202011060608,[In Press]
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毛乌素沙地东南缘人工林樟子松根系吸水来源与影响因素
裴艳武1, 黄来明2, 邵明安2, 李荣磊1, 张应龙3
1.西北农林科技大学资源环境学院;2.中国科学院地理科学与资源研究所;3.神木生态协会
摘要:
水资源短缺是我国西北旱区沙漠化防治和植被恢复重建的主要限制因子。揭示典型治沙植物根系吸水来源及其主控因子可为该地区科学治沙和水资源高效利用提供依据。本研究选取毛乌素沙地东南缘圪丑沟小流域樟子松人工林(18 – 20 年)为研究对象,通过定期采集和测定植物木质部水及其各种潜在水源(降水、土壤水和地下水)的氢氧同位素组成(δ2H和δ18O),结合多元线性混合模型研究樟子松根系吸水来源、动态变化特征及其影响因素。结果表明:监测期间(6—11月)樟子松木质部水、降水、土壤水和地下水的δ2H值变化范围分别为−69.95‰~ −49.25‰、−144.81‰ ~ −6.60‰、−83.62‰ ~ −48.57‰和−65.63‰ ~ −53.65‰,δ18O值变化范围分别为−8.77‰ ~ −8.21‰、−18.86‰~ −2.07‰、−9.45‰ ~ −6.54‰和−9.97‰ ~ −8.26‰。雨季(7—9月)降雨量、土壤含水量和地下水位分别高于旱季(6月,10月和11月)24.8 ~ 90.10 mm,3.36 ~ 8.40%和5 ~ 15 cm。樟子松根系在6月主要利用深层土壤水(> 90 cm)(15.40%)和地下水(70.10%),7—9月逐渐转变为以吸收浅层土壤水(< 80 cm)为主(61.03%),10—11月随着降雨量减少,深层土壤水(> 70 cm)和地下水对樟子松根系吸水的贡献比雨季(7—9月)分别增加5.82% ~ 28.00%和20.64% ~ 23.30%。毛乌素沙地樟子松人工林根系吸水来源受土壤水分供耗和地下水位季节波动的共同影响。
关键词:  毛乌素沙地  樟子松  稳定同位素  浅层地下水
基金项目:国家自然科学基金项目 (41601221)、中国科学院战略性先导科技专项(XDA23070202)、中国科学院青年创新促进会会员项目(2019052)、中国科学院地理科学与资源研究所秉维优秀青年人才项目(2017RC203)和中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室开放基金项目(A314021402-2010) 资助
Root Water Source of Pinus sylvestris L. var. Mongholica Litv. and Influencing Factors in the Southeastern Part of Mu Us Sandy Land, China
PEI Yanwu1, HUANG Laiming2, SHAO Mingan2, lI Ronglei1, ZHNAG Yinglong3
1.College of Natural Resources and Environment,Northwest A&F University;2.Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographic Sciences and Natural Resources Research;3.Shenmu Ecological Association
Abstract:
Water shortage is the main limiting factor for vegetation restoration and desertification control in the arid region of northwestern China. 【Objective】Investigation of the root water source and influencing factors of typical plants used for desertification control can provide a basis for scientific sand control and efficient water use in the region.【Method】Pinus sylvestris L. var. mongholica Litv. (P. sylvestris) is an evergreen coniferous tree of the Pinus genus. It is widely used in wind sheltering and sand fixation in the north of China because of its strong root system and ecological adaptability. In this study, the hydrogen and oxygen isotope composition (δ2H and δ18O) of plant xylem water and its potential water sources (precipitation, soil water and groundwater) were measured monthly from June to November 2018 in an artificial P. sylvestris forest (18~20 a). The experiment was carried out in the Gechougou watershed in the southeastern part of Mu Us Sandy Land. The dynamic changes and controls of root water sources were studied by the multiple linear mixed models. 【Result】Our results showed that the range of δ2H was −69.95‰ ~ −49.25 ‰, −144.81‰~−6.60‰, −83.62‰~−48.57 ‰ and −65.63‰ ~ −53.65 ‰ for xylem water, precipitation, soil water and groundwater, respectively. Also, the range of δ18O was −8.77‰~−8.21‰, −18.86‰~−2.07‰, −9.45‰~−6.54‰ and −9.97‰~−8.26‰, respectively, during the period monitored (June–November). The weighted mean values of δ2H and δ18O in soil water were between the precipitation and groundwater due to the influence of precipitation infiltration and groundwater recharge. Rainfall amount, soil water content and groundwater level in the rainy season (July–September) were 24.80~90.10 mm, 3.36%~8.40% and 5~15 cm higher than that in the dry season (June, October, November). Iso-source model predicted that P. sylvestris mainly used the nearly saturated layer water (>90 cm) (15.40%) and groundwater (70.10%) in June. However, from July to September, the root used water source mainly came from the active and stable soil layer (<80 cm) (61.03%) with the increase in rainfall. Compared with the rainy season (July–September), the contribution of the nearly saturated layer (>70 cm) and groundwater to the root water source increased by 5.82%~28.00% and 20.64%~23.30% in October and November when precipitation decreased. During the detection periods, the average ratio of absorption and utilization by P. sylvestris root from the active layer, stable layer, nearly saturated layer and groundwater were 21.48%, 31.13%, 16.42% and 30.98%, respectively. The dependence on groundwater for P. sylvestris was significantly higher than that of other soil layers, which may be prejudice to survival under extreme drought environments in the future.【Conclusion】The soil water content was positively correlated with the root water absorption of P. sylvestris. The uplift and decline of groundwater level significantly changed the position of the nearly saturated soil layer, and then affected the absorption and utilization ratio of P. sylvestris from different potential water sources. Therefore, the root water source of artificial P. sylvestris forest was affected by both supply-consumption dynamics of soil water and seasonal fluctuation of groundwater level. This study provides a useful method that identified the absorption and utilization ratio of water by plants from different potential water resources, which will be significant for vegetation restoration in the Mu Us Sandy Land soil-plant ecosystems.
Key words:  Mu Us Sandy Land, P. sylvestris., Stable isotope, Shallow groundwater