| 引用本文: | 徐 冰,李 想,张紫森,等.拉萨河谷喷灌双季饲草作物系数与土壤蒸发研究[J].灌溉排水学报,2024,43(2):31-40. |
| XU Bing,LI Xiang,ZHANG Zisen,et al.拉萨河谷喷灌双季饲草作物系数与土壤蒸发研究[J].灌溉排水学报,2024,43(2):31-40. |
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| 摘要: |
| 【目的】探究作物指标与作物系数、土壤蒸发之间的关系，为提高拉萨河谷喷灌蒸散发计算精度，制定适时适量的双季饲草灌溉制度提供理论支撑。【方法】通过微型蒸渗仪实测蒸散量与PM法计算参考作物的比值?实测作物系数对PM法修正的单作物系数进行评价，分析误差水平及原因；基于自制株间土壤蒸发仪，获得株间土壤蒸发（E）与蒸散量（ET）的分摊比例（E/ET），建立实测Kc及E/ET与LAI、SPAD之间的关系。【结果】采用FAO-56推荐单作物系数修正法，对拉萨河谷小黑麦、燕麦单作物系数进行修正，小黑麦和燕麦初始生长期、生长中期和生长后期的作物系数分别为0.45和0.94，1.22和1.16，0.49和0.31。小黑麦全生育期土壤蒸发占蒸散量的44.8%，苗期-越冬期、越冬-返青期、返青-拔节期、拔节-抽穗期、抽穗-刈割期土壤蒸发占蒸散量比例分别为93.4%、94.8%、61.8%、22.2%和13.8%；燕麦苗期-分蘖期、分蘖-拔节期、拔节-抽穗期、抽穗-刈割期土壤蒸发占蒸散量比例分别为98.9%、79.1%、31.7%和16.8%。土壤蒸发在双季饲草种植过程中占蒸散量比例超过44%，减少土壤蒸发以提高水分利用效率的潜力较大。【结论】双季饲草实测作物系数、土壤蒸发占蒸散量比例与叶面积指数、叶绿素显著相关且呈线性或非线性函数关系。在单作物系数法基础上增加作物指标可以修正双季饲草蒸散的计算精度，通过构建数学模型使作物指标能直接模拟该地区作物土壤蒸发、间接模拟蒸散发全过程。 |
| 关键词: 拉萨河谷；喷灌；双季饲草；作物系数；土壤蒸发 |
| DOI：10.13522/j.cnki.ggps.2023197 |
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| Relationship between crop coefficient and soil evaporation in forage grassland under sprinkler irrigation in Lhasa Valley |
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XU Bing, LI Xiang, ZHANG Zisen, REN Jie, LI Zekun
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1. Yinshanbeilu Grassland Eco-hydrology National Observation and Research Station, China Institute of Water Resources and Hydropower Research, Beijing 100038, China; 2. Institute of Water Resources for Pastoral Area, China Institute of
Water Resources and Hydropower Research, Hohhot 010020, China; 3. College of Water Conservancy and Civil Engineering,
Inner Mongolia Agricultural University, Hohhot 010018, China; 4. Baotou Reservoir Management Center, Baotou 014030, China
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| Abstract: |
| 【Objective】Crop coefficient and soil evaporation are two important parameters for calculating evapotranspiration in terrestrial ecosystems but they are dependent on many factors. In this paper, we investigate their correlation for a forage grassland. 【Method】 The experiment was conducted in a forage grassland (Triticale and Oat) irrigated by sprinkler irrigation at the Lhasa Valley. Evapotranspiration (ET) was measured from a micro-lysimeter and the potential evapotranspiration was calculated using the PM method. The ratio of the former to the latter was the ground-truth crop coefficient (Kc). This crop coefficient was used to evaluate the single-crop coefficient estimated using the modified PM method. We also measured the inter-plant soil evaporation (E) using an in-house instrument to estimate the E/ET ratio. The relationship between Kc and E/ET, as well as their dependence on leaf area index (LAI) and SPAD were established. 【Result】 Using the correction method recommended by FAO-56, the crop coefficient of Triticale and Oat in the Lhasa valley at initial, middle and end of their growth stage was Kc ini=0.45, Kc mid=1.22 and Kc end=0.49 for the Triticale, and Kc ini=0.94, Kc mid=1.16 and Kc end=0.31 for the Oat. For the Triticale, soil evaporation accounted for 44.8% of the evapotranspiration during the whole growth, and 93.4%, 94.8%, 61.8%, 22.2% and 13.8% during the seedling-overwintering, overwintering-replanting, replanting-jointing, jointing-heading and heading-mowing stage, respectively. For the Oat, soil evaporation accounted for 98.9%, 79.1%, 31.7% and 16.8% of the evapotranspiration from seedling to tillering, tiller to jointing, jointing to heading and heading to mowing stages, respectively. Overall, soil evaporation accounted for more than 44% of the evapotranspiration and it is hence potential to improve water use efficiency by reducing soil respiration. The measured crop coefficient and the ratio of soil evaporation to evapotranspiration were significantly correlated with LAI and SPAD linearly or nonlinearly. 【Conclusion】 The measured crop coefficient, ratio of soil evaporation to evapotranspiration of the two-season forage grassland are significantly correlated to LAI and SPAD. Adding a crop indicator to the single crop coefficient can improve the accuracy of the calculated evapotranspiration. Through mathematical models, the crop indicators can simulate evapotranspiration. |
| Key words: Lhasa Valley; sprinkler irrigation; two-season forage grass; crop coefficient; soil evaporatio |
