| 左强,孙炎鑫,杨培岭.应用Microlysimeter 研究作物根系吸水特性[J].水利学报,1998,29(6):0069-0077 |
| 应用Microlysimeter 研究作物根系吸水特性 |
| Study on water uptake by the winter wheat's roots with the application of Microlysimeter |
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| DOI： |
| 中文关键词: 根系吸水 模型 数值模拟 Microlysimeter 土面蒸发 蒸腾 |
| 英文关键词: water uptake by roots model numerical simulation Microlysimeter evaporation transpiration |
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| 摘要点击次数: 1666 |
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| 中文摘要: |
| 本文应用Microlysimeter现场原位测定土面蒸发，以此为上边界条件，运用土壤动力学原理，提出了一种新的模拟根系吸水速率S(z,t)的方法，该方法与所选取的平均时段δt密切相关，研究表明：在冬小麦蒸腾速率较弱的前期及较强的后期，分别选取δt=10d,5d模拟S(z,t)可以获得较好的结果，分析冬小麦根系吸水速率的模拟结果可知：冬小麦根系吸水在灌浆-乳熟期达最高峰；若近地表水分充足，则吸水高峰出现在土壤上部，否则根系下扎，吸水高峰随之下移。 |
| 英文摘要: |
| Based on the theory of soil water dynamics and more practical and rational upper boundary condition of one dimensional vertical unsaturated flow, a new approach to modeling water uptake rates by roots S(z, t) is put forward in this paper by using the evaporation data from the soil surface measured in situ by Microlysimeter. The accuracy of the modeling result depends on the value of averaging time step δt, in the earlier growth stages of plants, δtcan be set bigger than that in the later stages due to the fact of weaker transpiration. As for the winter wheat, the simulated soil moisture content profiles are in reasonable agreement with the measured if δt is selected as 10d in the earlier stages and 5d in the later growth periods respectively. The winter wheat's S(z, t) in the stages between jointing and harvest has been simulated with the application of the new proposed numerical model about water uptake by roots. The results have shown that: 1, the maximum water uptake rate of the winter wheat appears in the stages between milking and milky maturity, 2, the roots of the winter wheat grow towards the soil layer with abundant and easier to be absorbed water, namely, if water is sufficient near the soil surface, the water absorbing peak of roots will appear in the upper soil profile, otherwise, the roots will stretch deeper, and the peak move to the lower layer accordingly. |
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