摘要:探讨柴达木盆地灌区作物水分利用特征，可为灌溉系统设计和水资源高效利用提供理论依据。以柴达木盆地怀头他拉灌区主要作物枸杞为对象，将枸杞潜在水源划分为浅层（0~20 cm）、中层（20~60 cm）和深层（60~100 cm）土壤水，利用稳定氧同位素示踪技术以及MixSIAR模型定量研究不同田间管理模式下[平作裸地（CK）、平作覆膜（MF）和垄作覆膜（MR）]枸杞根系水分吸收特征。结果表明：萌芽展叶期浅层土壤水分环境相对较好，CK和MF处理枸杞主要吸收浅层土壤水分，利用比例分别为45.9%和37.7%，MR处理对浅层、中层和深层土壤水源的利用比例相当；开花坐果期各层土壤水分都有所提高，相比于CK，MF处理浅层土壤水分利用比例增加13.5%，MR处理浅层土壤水分利用比例减少11.1%；果熟期枸杞蒸腾耗水量增加，相比于CK，MF和MR处理对浅层土壤水分的利用比例分别增加11.7%和24.0%；落叶期浅层土壤含水量较低，3个处理都主要吸收深层土壤水分。浅层土壤水源的利用比例与该层土壤水分呈正相关，枸杞对浅层土壤水分变化较敏感。3种管理模式下枸杞根系水分吸收来源差异明显。覆膜和垄作措施均提高了土壤含水量。相比于CK，MF和MR处理枸杞都增加了对浅层水源的利用。MR处理下土壤水分状况较好且枸杞根系水分吸收利用模式更加灵活，对柴达木盆地灌区是一种较优的田间水分管理模式。
关键词:枸杞/
干旱灌区/
根系水分吸收/
土壤水分/
管理模式/
MixSIAR模型
Abstract:Lycium barbarum (Chinese wolfberry) helps ecosystems by providing storm protection and sand immobilization, and it is also a cash crop for Qaidam Basin farmers. L. barbarum is a common crop in arid regions, such as the Qaidam Basin, China, but drought and water scarcity have constrained industry development. Identifying crop water-use strategies is important for designing efficient irrigation systems. Seasonal L. barbarum water-use was investigated in 2018 in the Qaidam Basin Huaiten Tula Irrigation Area. Natural oxygen stable isotope tracers were used to measure the oxygen stable isotope composition (δ18O) of water in the xylem and soil of L. barbarum orchards with three field management practices (conventional flat planting, CK; flat-planting full-film mulching, MF; and ridge-furrow full-film mulching, MR). The soil water contribution to root water uptake was analyzed using the MixSIAR Bayesian mixing practices. The soil water and soil water δ18O profile distribution showed that all soil layers (shallow: 0-20 cm; middle: 20-60 cm; and deep: 60-100 cm) were potential water sources for L. barbarum. During the sprouting period (starting May 25, 2018), CK and MF plants used primarily shallow soil water, accounting for 45.9% and 37.7% of the total water use, respectively, due to the larger amounts of shallow-layer soil water. MR plants used the same amount of water from each layer. During the blossom and fruiting period (starting July 9, 2018), the soil water content increased in all soil layers. Compared with that in CK plants, the shallow-layer soil water use increased by 13.5% in MF plants and decreased by 11.1% in MR plants. During the fruit ripening period (starting July 30, 2018), water consumption increased. Compared with that in CK plants, shallow-layer soil water use increased in MF (by 11.7%) and MR (by 24.0%) plants. During the defoliation period (starting September 22, 2018), the water content in the shallow-layer soil was lower than that in the other soil layers, and all of the treatment groups used primarily deep-layer soil water. These results showed that shallow-layer soil contributions were positively correlated with water content, indicating that L. barbarum is sensitive to changes in the shallow-layer soil water. There were significant differences in the root water uptake among the three field management practices. Mulching and ridge-furrow treatments increased the soil water content and, compared with that in CK plants, the MF and MR treatments increased the shallow-layer soil water use. The soil water content was higher and the water source was more flexible during the growth period with the MR treatment than with the CK and MF treatments. These results suggest that MR is a better field water management practice for promoting the sustainable and healthy development of L. barbarum orchards.
Key words:Lycium barbarum/
Arid oasis irrigation area/
Root water uptake/
Soil water/
Management practices/
MixSIAR model
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