基于四端法和时域反射法的土壤电导率测量研究
|
摘要
为探究电流-电压四端法和时域反射法两种接触式测量方法在不同质地土壤和不同含盐量、含水率土壤的适用性,设计基于"电流-电压"四端法的土壤电导率测量仪,对其标定并与时域反射法进行对比试验。标定结果表明,当电导率在0～14 mS/cm范围内时,该仪器具有较高准确度。不同含水率的对比试验结果表明,四端法和时域反射法在一定含盐量范围内都具有较好的线性度;而当砂质壤土含水率为20%、含盐量大于0. 6%时,四端法电导率测量仪测得的电导率基本保持不变;当粉质黏土含水率较低和较高时,电导率均变化不大,因此在使用时应尽量避免在土壤含水率较低和较高时进行测量。不同质地土壤的对比试验表明,四端法和时域反射法均在含盐量较低时受土壤质地影响较小,在含盐量较高时受土壤质地影响较大。
Obtaining farmland information quickly and efficiently is the basis of precision agriculture."Current-voltage"four-terminal method and time domain reflectrometry( TDR) are two main methods for contact measurement of soil conductivity. A soil conductivity instrument based on the principle of"current-voltage"four-terminal method was designed,which was calibrated and compared with TDR to explore the applicability of the two methods. The calibration results showed that when the electrical conductivity was in the range of 0 and 14 mS/cm,the determination coefficient R~2 reached 0. 960,and the instrument had high accuracy in this range. The results of soil contrast test showed that the fourterminal method and TDR had good linearity under the condition of low salt content and water content,but when the salt content of sandy loam was more than 0. 6%,the change of conductivity measured by four-terminal method tended to be smooth. When the moisture content of silty clay was 20% and 25%,the measurement data of the two instruments were basically the same,so it was needed to try best to avoid measuring when the soil moisture content was high. The comparative experiments under different texture soils showed that the four-terminal method and TDR were greatly affected by the soil type,and the higher the clay content of the soil was,the smaller the conductivity of the soil was. During the test,the fourterminal conductivity meter can measure in real time,but the time of each TDR measurement was about 20 s,which was not conducive to real-time measurement.
Obtaining farmland information quickly and efficiently is the basis of precision agriculture."Current-voltage"four-terminal method and time domain reflectrometry( TDR) are two main methods for contact measurement of soil conductivity. A soil conductivity instrument based on the principle of"current-voltage"four-terminal method was designed,which was calibrated and compared with TDR to explore the applicability of the two methods. The calibration results showed that when the electrical conductivity was in the range of 0 and 14 mS/cm,the determination coefficient R~2 reached 0. 960,and the instrument had high accuracy in this range. The results of soil contrast test showed that the fourterminal method and TDR had good linearity under the condition of low salt content and water content,but when the salt content of sandy loam was more than 0. 6%,the change of conductivity measured by four-terminal method tended to be smooth. When the moisture content of silty clay was 20% and 25%,the measurement data of the two instruments were basically the same,so it was needed to try best to avoid measuring when the soil moisture content was high. The comparative experiments under different texture soils showed that the four-terminal method and TDR were greatly affected by the soil type,and the higher the clay content of the soil was,the smaller the conductivity of the soil was. During the test,the fourterminal conductivity meter can measure in real time,but the time of each TDR measurement was about 20 s,which was not conducive to real-time measurement.
引文
[1]朱成立,舒慕晨,张展羽,等.咸淡水交替灌溉对土壤盐分分布及夏玉米生长的影响[J].农业机械学报,2017,48(10):206-225.ZHU Chengli,SHU Muchen,ZHANG Zhanyu,et al.Effect of alternate irrigation with fresh and brackish water on saline distribution characteristics of soil and growth of summer maize[J].Transactions of the Chinese Society for Agricultural Machinery,2017,48(10):206-225.(in Chinese)
[2]CHO Y,CHUNG S K A.Soil physical property estimation from soil strength and apparent electrical conductivity sensor data[J].Biosystems Engineering,2016,152:68-78.
[3]BAI W,KONG L,GUO A.Effects of physical properties on electrical conductivity of compacted lateritic soil[J].Journal of Rock Mechanics and Geotechnical Engineering(English Edition),2013,5(5):406-411.
[4]DOMINGOS S M V,DANIEL M Q,FRANCISCO A C P,et al.The relationship between apparent soil electrical conductivity and soil properties[J].Revista Ciência Agron8mica,2012,43(4):683-690.
[5]GISES K,TIEMANN R.Determination of the complex permittivity from thin-sample time domain reflectometry improved analysis of the step response waveform[J].Advances in Molecular Relaxation Processes,1975,7(1):45-59.
[6]孙宇瑞.土壤含水率和盐分对土壤电导率的影响[J].中国农业大学学报,2000,5(4):39-41.SUN Yurui.Experimental survey for the effects of soil water content and soil salinity on soil electrical conductivity[J].Journal of China Agricultural University,2000,5(4):39-41.(in Chinese)
[7]胡克林,李保国,陈德立,等.农田土壤水分和盐分的空间变异性及其协同克立格估值[J].水科学进展,2001,12(4):460-466.HU Kelin,LI Baoguo,CHEN Deli,et al.Spatial variability of soil water and salt in field and their estimations by the co Kriging[J].Advances in Water Science,2001,12(4):460-466.(in Chinese)
[8]FRIEDMAN S P.Soil properties influencing apparent electrical conductivity:a review[J].Computers&Electronics in Agriculture,2005,46(1):45-70.
[9]DALTON F N,HERKELRATH W N,RAWLINS D S,et al.Time-domain reflectometry:simultaneous measurement of soil water content and electrical conductivity with a single probe[J].Science,1984,224:989-990.
[10]ROBINSON D A,JONES S B,WRAITH M J,et al.A review of advances in dielectric and electrical conductivity measurement in soils using time domain reflectometry[J].Vadose Zone Journal,2003,2(4):444-475.
[11]SKIERUCHA W,WILCZEK A,SZYPLOWSKA A,et al.A TDR-based soil moisture monitoring system with simultaneous measurement of soil temperature and electrical conductivity[J].Sensors,2012,12(10):13545-13566.
[12]TADAOMI S,HARUYUKI F,MITSUHIRO I.Calibration and simultaneous monitoring of soil water content and salinity with capacitance and four-electrode probes[J].American Journal of Environmental Sciences,2008,4(6):683-692.
[13]SHEA P F,LUTHIN J N.An investigation of the use of the four-electrode probe for measuring soil salinity in situ[J].Soil Science,2012,92(5):331-339.
[14]PEDRERA-PARRILLA A,VIJVER E V D,MEIRVENN M V,et al.Apparent electrical conductivity measurements in an olive orchard under wet and dry soil conditions:significance for clay and soil water content mapping[J].Precision Agriculture,2016,17(5):1-15.
[15]曾庆猛,马道坤,林剑辉,等.面向车载式测量的土壤含水量与电导率复合传感器设计[J].农业机械学报,2010,41(9):163-167.ZENG Qingmeng,MA Daokun,LIN Jianhui,et al.On-the-go measurement oriented combined sensor design for soil moisture content and electrical conductivity[J].Transactions of the Chinese Society for Agricultural Machinery,2010,41(9):163-167.(in Chinese)
[16]STADLER A,RUDOLPH S,KUPISCH M,et al.Quantifying the effects of soil variability on crop growth using apparent soil electrical conductivity measurements[J].European Journal of Agronomy,2015,64:8-20.
[17]MURATA H,FUTAGAWA M,KUMAZAKI T,et al.Millimeter scale sensor array system for measuring the electrical conductivity distribution in soil[J].Computers&Electronics in Agriculture,2014,102(1):43-50.
[18]PERSON M.Soil solution electrical conductivity measurements under transient conditions using time domain reflectometry[J].Soil Science Society of America Journal,1997,61:997-1003.
[19]TOPP G C,YANUKA M,ZEBCHUK W D,et al.Determination of electrical conductivity using time domain reflectometry:soil and water experiments in coaxial lines[J].Water Resources Research,1988,24:945-952.
[20]ZHANG N,FAN G,LEE K H,et al.Simultaneous measurement of soil water content and salinity using a frequency-response method[J].Soil Science Society of America Journal,2004,68(5):1515-1525.
[21]赵燕东,董晓晨,李宁.线区域尺度土壤水分实时测量方法研究[J].农业机械学报,2015,46(6):168-174.ZHAO Yandong,DONG Xiaochen,LI Ning.Real-time soil moisture measurement method on line scale[J].Transactions of the Chinese Society for Agricultural Machinery,2015,46(6):168-174.(in Chinese)
[22]PONIZOVSKY A A,CHUDINOVA S M,PACHEPSKY Y A.Performance of TDR calibration models as affected by soil texture[J].Journal of Hydrology,1999,218(1-2):35-43.
[2]CHO Y,CHUNG S K A.Soil physical property estimation from soil strength and apparent electrical conductivity sensor data[J].Biosystems Engineering,2016,152:68-78.
[3]BAI W,KONG L,GUO A.Effects of physical properties on electrical conductivity of compacted lateritic soil[J].Journal of Rock Mechanics and Geotechnical Engineering(English Edition),2013,5(5):406-411.
[4]DOMINGOS S M V,DANIEL M Q,FRANCISCO A C P,et al.The relationship between apparent soil electrical conductivity and soil properties[J].Revista Ciência Agron8mica,2012,43(4):683-690.
[5]GISES K,TIEMANN R.Determination of the complex permittivity from thin-sample time domain reflectometry improved analysis of the step response waveform[J].Advances in Molecular Relaxation Processes,1975,7(1):45-59.
[6]孙宇瑞.土壤含水率和盐分对土壤电导率的影响[J].中国农业大学学报,2000,5(4):39-41.SUN Yurui.Experimental survey for the effects of soil water content and soil salinity on soil electrical conductivity[J].Journal of China Agricultural University,2000,5(4):39-41.(in Chinese)
[7]胡克林,李保国,陈德立,等.农田土壤水分和盐分的空间变异性及其协同克立格估值[J].水科学进展,2001,12(4):460-466.HU Kelin,LI Baoguo,CHEN Deli,et al.Spatial variability of soil water and salt in field and their estimations by the co Kriging[J].Advances in Water Science,2001,12(4):460-466.(in Chinese)
[8]FRIEDMAN S P.Soil properties influencing apparent electrical conductivity:a review[J].Computers&Electronics in Agriculture,2005,46(1):45-70.
[9]DALTON F N,HERKELRATH W N,RAWLINS D S,et al.Time-domain reflectometry:simultaneous measurement of soil water content and electrical conductivity with a single probe[J].Science,1984,224:989-990.
[10]ROBINSON D A,JONES S B,WRAITH M J,et al.A review of advances in dielectric and electrical conductivity measurement in soils using time domain reflectometry[J].Vadose Zone Journal,2003,2(4):444-475.
[11]SKIERUCHA W,WILCZEK A,SZYPLOWSKA A,et al.A TDR-based soil moisture monitoring system with simultaneous measurement of soil temperature and electrical conductivity[J].Sensors,2012,12(10):13545-13566.
[12]TADAOMI S,HARUYUKI F,MITSUHIRO I.Calibration and simultaneous monitoring of soil water content and salinity with capacitance and four-electrode probes[J].American Journal of Environmental Sciences,2008,4(6):683-692.
[13]SHEA P F,LUTHIN J N.An investigation of the use of the four-electrode probe for measuring soil salinity in situ[J].Soil Science,2012,92(5):331-339.
[14]PEDRERA-PARRILLA A,VIJVER E V D,MEIRVENN M V,et al.Apparent electrical conductivity measurements in an olive orchard under wet and dry soil conditions:significance for clay and soil water content mapping[J].Precision Agriculture,2016,17(5):1-15.
[15]曾庆猛,马道坤,林剑辉,等.面向车载式测量的土壤含水量与电导率复合传感器设计[J].农业机械学报,2010,41(9):163-167.ZENG Qingmeng,MA Daokun,LIN Jianhui,et al.On-the-go measurement oriented combined sensor design for soil moisture content and electrical conductivity[J].Transactions of the Chinese Society for Agricultural Machinery,2010,41(9):163-167.(in Chinese)
[16]STADLER A,RUDOLPH S,KUPISCH M,et al.Quantifying the effects of soil variability on crop growth using apparent soil electrical conductivity measurements[J].European Journal of Agronomy,2015,64:8-20.
[17]MURATA H,FUTAGAWA M,KUMAZAKI T,et al.Millimeter scale sensor array system for measuring the electrical conductivity distribution in soil[J].Computers&Electronics in Agriculture,2014,102(1):43-50.
[18]PERSON M.Soil solution electrical conductivity measurements under transient conditions using time domain reflectometry[J].Soil Science Society of America Journal,1997,61:997-1003.
[19]TOPP G C,YANUKA M,ZEBCHUK W D,et al.Determination of electrical conductivity using time domain reflectometry:soil and water experiments in coaxial lines[J].Water Resources Research,1988,24:945-952.
[20]ZHANG N,FAN G,LEE K H,et al.Simultaneous measurement of soil water content and salinity using a frequency-response method[J].Soil Science Society of America Journal,2004,68(5):1515-1525.
[21]赵燕东,董晓晨,李宁.线区域尺度土壤水分实时测量方法研究[J].农业机械学报,2015,46(6):168-174.ZHAO Yandong,DONG Xiaochen,LI Ning.Real-time soil moisture measurement method on line scale[J].Transactions of the Chinese Society for Agricultural Machinery,2015,46(6):168-174.(in Chinese)
[22]PONIZOVSKY A A,CHUDINOVA S M,PACHEPSKY Y A.Performance of TDR calibration models as affected by soil texture[J].Journal of Hydrology,1999,218(1-2):35-43.