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基于低頻濾波法的T-TDR含水率測(cè)量方法研究
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國家自然科學(xué)基金資助項(xiàng)目(51309193)、高等學(xué)校學(xué)科創(chuàng)新引智計(jì)劃(111計(jì)劃)資助項(xiàng)目(B12007)、陜西省農(nóng)業(yè)攻關(guān)資助項(xiàng)目(2012K02-15)和西北農(nóng)林科技大學(xué)基本科研業(yè)務(wù)費(fèi)資助項(xiàng)目(QN2011128)


Measurement of Soil Moisture with T-TDR Probe Based on LFF Method
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    摘要:

    為了解決T-TDR(Thermo-time domain reflectometry)探針短,土壤含水率測(cè)量效果差等技術(shù)問題,提出了一種低頻濾波法LFF(Low frequency filter)進(jìn)行TDR波形分析的計(jì)算模型。通過對(duì)TDR波形快速傅里葉變換,得到組成TDR波形的頻譜,對(duì)其低頻濾波后重新快速傅里葉反變換,可實(shí)現(xiàn)LFF變換。試驗(yàn)通過4種土壤,每種5個(gè)含水率的20個(gè)土樣進(jìn)行測(cè)試,通過LFF法和傳統(tǒng)WINTDR法對(duì)比,結(jié)果表明LFF法具有較好的計(jì)算結(jié)果,其與干燥法的決定系數(shù)R2達(dá)0.9835。LFF法不僅有效提高了T-TDR短針土壤含水率的測(cè)試精度,還簡(jiǎn)化了土壤含水率測(cè)試校驗(yàn)程序,提高了測(cè)試效率。

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    In order to improve the accuracy of soil moisture measurement by T-TDR (Thermo-time domain reflectometry) probe because the needles of T-TDR were too short, this paper presented a new TDR waveform analysis method named LFF (Low frequency filter). The TDR waveform was transformed by fast Fourier transform algorithm, and then the spectrum of TDR wave was obtained. The LFF transformation could be realized by filtering the low frequency of TDR wave spectrum and transforming it by inverse fast Fourier transform. Four kinds of soil samples prepared by five different volumetric water content with twenty specimen, were used in the experiment. Through comparing the LFF method and the traditional WINTDR method with the oven drying method respectively, LFF method showed better results. The correlation coefficient of LFF with the oven drying method was R2=0.9835. LFF method could improve the soil moisture measurement accuracy of T-TDR and simplify the test validation procedures and improve the test efficiency.

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許景輝,馬孝義,Sally D Logsdon.基于低頻濾波法的T-TDR含水率測(cè)量方法研究[J].農(nóng)業(yè)機(jī)械學(xué)報(bào),2014,45(6):172-176. Xu Jinghui, Ma Xiaoyi, Sally D Logsdon. Measurement of Soil Moisture with T-TDR Probe Based on LFF Method[J]. Transactions of the Chinese Society for Agricultural Machinery,2014,45(6):172-176.

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  • 收稿日期:2014-01-21
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  • 在線發(fā)布日期: 2014-06-10
  • 出版日期: 2014-06-10