Comparison of three dielectric moisture sensors for measurement of water in saline sandy soil
Comparison of three dielectric moisture sensors for measurement of water in saline sandy soil
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DOI：
10.1111/j.1475-2743.2008.00154.x
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发表时间：
2008-06-01
影响因子：
3.8
通讯作者：
Uzoma, K. C.
中科院分区：
文献类型：
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作者：
Inoue, M.;Ahmed, B. A. Ould;Uzoma, K. C.
可用于测量土壤含水量的传感器类型的数量有所增加，但在盐渍土中比较其性能的调查需要澄清。在这项研究中，市售的，低成本的土壤水分传感器的性能[时域反射仪（TDR），PR 1和WET]，所有测量土壤水的介电常数的变化，在实验室条件下，在含盐桑迪土壤进行了评估。在同一桑迪土壤上进行了滴灌高粱（Sorcium bicolor L.）CV. Moench）在一个温室里。每天用盐水（ECw：9.4dS/m）或淡水（0.11dS/m）灌溉植物。灌溉量相当于蒸发皿蒸发量的100%。结果表明，测量精度强烈依赖于土壤的盐分。当盐度水平超过4 dS/m [标准误差的均方根（RMSE）= 0.009 cm（3）/cm（3）]时，PR 1传感器高估了体积含水量（θ）。WET传感器显著高估了θ，而与盐度水平无关（RMSE = 0.014 cm（3）/cm（3））。TDR传感器以更高的精度（RMSE = 0.007 cm（3）/cm（3））估计θ，因此可以被认为比其他两个传感器更可靠。校准受到水的盐度水平的强烈影响，因此我们建议修改校准方程以考虑盐度。
The number of sensor types available for measuring soil water content has increased but investigations to compare their performance in saline soils needs clarification. In this study the performance of commercially available, low-cost soil moisture sensors [time domain reflectometry (TDR), PR1 and WET], all measuring changes in the dielectric constant of the soil water, was evaluated under laboratory conditions in a saline sandy soil. The three sensors were also tested in the same sandy soil growing drip irrigated sorghum (Sorghum bicolor L. cv. Moench) in a greenhouse. Plants were irrigated daily with either saline water (ECw: 9.4 dS/m) or fresh water (0.11 dS/m). The volume of irrigation was equivalent to 100% of the pan evaporation. The results showed that measurement accuracy was strongly dependent on the salinity of the soil. The PR1 sensor overestimated volumetric water content (theta) when the salinity level exceeded 4 dS/m [root mean square of the standard error (RMSE) = 0.009 cm(3)/cm(3)]. The WET sensor significantly overestimated theta irrespective of the salinity level (RMSE = 0.014 cm(3)/cm(3)). The TDR sensor estimated theta with more accuracy (RMSE = 0.007 cm(3)/cm(3)) and thus can be considered as more reliable than the other two sensors. The calibrations were strongly affected by the salinity level of the water, so we recommend that calibration equations are modified to take account of salinity.