干旱区研究

干旱区研究 ›› 2023, Vol. 40 ›› Issue (7): 1117-1130.doi: 10.13866/j.azr.2023.07.09

• 水土资源 • 上一篇    下一篇

蒸散分离的玉米水分利用效率变化及影响因素

庄淏然1(),冯克鹏1,2,3(),许德浩1   

  1. 1.宁夏大学土木与水利工程学院，宁夏 银川 750021
    2.旱区现代农业水资源高效利用教育部工程研究中心，宁夏 银川 750021
    3.宁夏节水灌溉与水资源调控工程技术研究中心，宁夏 银川 750021
  • 收稿日期:2023-03-08 修回日期:2023-05-17 出版日期:2023-07-15 发布日期:2023-08-01
  • 通讯作者: 冯克鹏. E-mail: fengkp@nxu.edu.cn
  • 作者简介:庄淏然（2000-），男，硕士研究生，主要从事蒸散发及水分利用效率研究. E-mail: 756771967@qq.com
  • 基金资助:
    国家重点研发计划项目(2021YFD1900600);宁夏自然科学基金重点项目(2021AAC02007);宁夏自然科学基金重点项目(2022AAC02007);宁夏高等学校科研项目(NGY2020006);宁夏高等学校一流学科建设项目(NXYLXK2021A03)

Changes, influencing factors and sensitivity of water use efficiency in maize farmland ecosystems based on evapotranspiration separation in the Ningxia irrigated area

ZHUANG Haoran1(),FENG Kepeng1,2,3(),XU Dehao1   

  1. 1. School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, Ningxia, China
    2. Engineering Research Center for Efficient Utilization of Modern Agricultural Water Resources in Arid Areas, Ministry of Education, Yinchuan 750021, Ningxia, China
    3. Ningxia Engineering Research Center for Water-saving Irrigation and Water Resources Control, Yinchuan 750021, Ningxia, China
  • Received:2023-03-08 Revised:2023-05-17 Online:2023-07-15 Published:2023-08-01

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摘要：

水分利用效率（WUE）是农田生态系统碳水循环的重要指标，对指导农业灌溉和提高水分生产力有重要意义。宁夏灌区是我国地处干旱气候带的大型灌区，其中，玉米种植面积最大。在涡度通量观测农田生态系统实际蒸散发（ET）的基础上，利用氢氧稳定同位素法将蒸散发分割为土壤蒸发（evaporation，E）、植物蒸腾（transpiration，T），并通过光能利用模型估算宁夏引黄灌区典型玉米农田生态系统的总初级生产力（GPP），计算群体水分利用效率WUET=GPP/T、生态系统水分利用效率WUEET=GPP/ET以及固有水分利用效率（Intrinsic Water Use Efficiency）IWUEVPD=（GPP·VPD）/ET三种水分利用效率，进而从函数响应关系、相关性以及敏感性三个方面分析不同水分利用效率与气温、饱和水汽压差（VPD）、CO2浓度、光合有效辐射以及土壤含水量等环境因子之间的关系。结果表明：宁夏引黄灌区玉米农田生态系统生长季的实际蒸散发变化呈单驼峰型，作物蒸腾与实际蒸散发的变化趋势相一致。WUET在生育期内呈“W型”变化，WUEET与IWUEVPD在生育期内呈“单峰型”变化，三种WUE的峰值出现在抽雄期，分别达到5.90 kg C·m-3·H2O、5.02 kg C·m-3·H2O和32.90 kg C·hPa·m-3·H2O，灌浆后期三种水分利用效率开始降低，玉米成熟晚期由于蒸腾微弱所以WUET略有增加。WUET、WUEET和IWUEVPD与土壤含水量显著正相关，相关度和敏感性最强；VPD与三种WUE显著负相关，相关度和敏感性最强次之；气温、光合有效辐射以及CO2浓度与三种WUE的负相关性但不是敏感因素。因此，在宁夏引黄灌区土壤水分和VPD是影响玉米农田生态系统WUE的关键因素。

关键词: 氢氧稳定同位素, 蒸散分离, 光能利用模型, 总初级生产力, 作物蒸腾

Abstract:

Water use efficiency (WUE) is an important indicator of the carbon-water cycle of farmland ecosystems and is of great significance for guiding agricultural irrigation and improving water productivity. Ningxia Irrigation area is a large-scale irrigation district located in the arid climate zone of China, where the corn planting area is the largest. Based on eddy flux observation of actual evapotranspiration (ET) of farmland ecosystems, this paper used the hydrogen and oxygen stable isotope method to segment evapotranspiration and estimated the total primary productivity (GPP) of typical maize farmland ecosystems in the Yellow River irrigation area of Ningxia using the LUE (Light Use Efficiency) model. Population Water Use Efficiency WUET = GPP/T, Ecosystem Water Use Efficiency WUEET = GPP/T, and Intrinsic Water Use Efficiency IWUEVPD = (GPP·VPD)/ET were calculated. Then, the relationship between different WUE and environmental factors, such as air temperature, saturated water vapor pressure difference, CO2 concentration, effective photosynthetic radiation, and soil water content was analyzed from three aspects: functional response relationship, correlation, and sensitivity. The result showed that the variation of actual evapotranspiration in the growing season of the maize agro-ecosystem in the Ningxia yellow irrigation area was single-humped, and the trends of crop transpiration and actual evapotranspiration were consistent. The variation of water use efficiency in the growing season was different among the three species, with WUET showing a “W-shaped” variation pattern during the growing season while WUEET and IWUEVPD showed a “single-hump” variation pattern. All three WUE peaks occurred at the male tasseling stage, reaching (5.90 kg C·m-3·H2O, 5.02 kg C·m-3·H2O, 32.9 kg C·hPa·m-3·H2O) respectively. The three kinds of water use efficiency began to decrease in the late filing period, and WUET increased slightly in the late ripening period due to weak transpiration. Among the five environmental factors, WUET, WUEET and IWUEVPD were positively correlated with soil water content, and the correlation and sensitivity were the strongest. The three water use efficiencies were significantly negatively correlated with VPD, with the second strongest correlation and sensitivity. Air temperature, photosynthetically active radiation, and CO2 concentration were negatively correlated with the three kinds of WUE but not critical factors. Therefore, soil moisture and VPD are the key factors affecting the WUE of the maize farmland ecosystem in the Yellow River irrigation area of Ningxia.

Key words: stable isotopes of hydrogen and oxygen, evapotranspiration separation, light use efficiency model, gross primary productivity, crop transpiration