Applicability of multiple length TDR probes to measure water distributions in an Andisol under different tillage systems in Japan
Applicability of multiple length TDR probes to measure water distributions in an Andisol under different tillage systems in Japan
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DOI：
10.1016/s0167-1987(01)00172-6
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发表时间：
2001-06-01
影响因子：
6.5
通讯作者：
Chikushi, J
中科院分区：
文献类型：
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作者：
Miyamoto, T;Kobayashi, R;Chikushi, J
在全球范围内，时间域反射仪(TDR)已成为测量土壤水分的一种方法。本研究的目的是研究在少耕和常规耕作条件下，多长度探头的TDR技术是否可以用来评估根区水分的分布。对三种不同堆积密度的Andisol(Hhyc Pachic Melanudands)进行了TDR标定，并进行了现场测量。对于三种不同体积密度的测量数据，分别检验了单个和三个单独的校准函数。对TDR法和重量法测得的水分含量进行了比较。尽管单一的校准函数在大于0.50m(3)m(-3)的湿度范围内倾向于高估，但标准偏差(S.D.)TdR与重力值之差为+/-0.035 m(3)m(-3)。该值仅比使用单独的校准函数获得的S.D.大+/-0.002 m(3)m(-3)。我们发现单一的校准函数对于描述不同容重的特定土壤的体积含水率和表观介电常数之间的关系是足够准确的。用多个长度探头在田间间歇性地进行最少耕作和常规耕作下的TDR测量。TDR技术可以很容易地确定水分分布，并表征不同耕作制度下的土壤水分状况。利用多个长度探头的TDR测量可以提供各种条件下作物产量与土壤环境关系的有用信息，并为改善土壤水分管理提供有用的信息。(C)2001 Elsevier Science B.V.保留所有权利。
Time domain reflectometry (TDR) has become increasingly popular worldwide for measuring soil moisture. The objective of this study was to show if the TDR technique with multiple length probes could be used to evaluate the distributions of water content in root zones under both minimum and conventional tillage conditions. TDR calibrations for an Andisol (Hydric Pachic Melanudands) with three different bulk densities were tested, and field measurements were conducted. A single as well as three separate calibration functions were examined for the measured data with three different bulk densities. The water contents measured by TDR and gravimetric sampling were compared to each other. Even though the single calibration function tended to overestimate at a moisture range larger than 0.50 m(3) m(-3), the standard deviation (S.D.) of the difference between the TDR and gravimetric values was +/-0.035 m(3) m(-3). This value was only +/-0.002 m(3) m(-3) larger than the S.D. obtained using the separate calibration functions. We found the single calibration function to be accurate enough for describing the relationship between volumetric water content and apparent dielectric constant for this specific soil with different bulk densities. The TDR measurements with multiple length probes were conducted intermittently under both minimum and conventional tillage in a field over time. The TDR technique easily determined water distributions, and characterized the soil moisture regime resulting from different tillage systems. The TDR measurement with multiple length probes can provide useful information on the relationship between crop yield and soil environment and for improving soil water management under various conditions. (C) 2001 Elsevier Science B.V. All rights reserved.