Date of Award

2010

Publisher

North Dakota State University

Document Type

Thesis

Degree Awarded

Master of Science (MS)

Program

Soil Science

Department

Soil Science

College

Agriculture, Food Systems and Natural Resources

Faculty Advisor

Desutter, Thomas M.

Description

Soil electrical conductivity (EC) can be used as a parameter to assist agricultural producers in making economically important management decisions. Since particular crops and crop varieties respond dynamically to soluble salt levels in relation to crop growth stage and soil moisture content, many management decisions regarding crop type and variety must be made prior to planting. Some crop stress factors could be removed or mitigated if a handheld EC meter could be implemented during the growing season. The objectives of this research were to 1) determine the accuracy of four handheld EC meters for measuring soil EC across a range of environmental temperatures of 15, 20 and 25° C, soil clay concentrations of 10.2, 17.8, 19.3, 32.3 and 50.4 %, and salt solutions containing NaMg- SO4 or Na-Mg-Cl at concentrations of approximately 0, 1, 2, 4 and 8 dS m-1 under controlled laboratory conditions; 2) identify functional differences of the meters that might pose problems for in-field use; and 3) determine if meter price is related to accuracy. The EC values provided by three of the handheld EC meters were significantly different than the standard meter at all treatment levels. Measurements at different temperatures of the standard KCI calibration solution (known EC 1.413 dS m ·1 ) varied by ±0.15, -0.01 to +0.16, -0.14 to -0.03, and ±0.03 dS m-1, for the Hanna Black (Hl993310), Hanna Blue {Hl98331), Field Scout, and SenslON 5 meters, respectively. When salinity was 3 dS m-1 or greater the difference between the test meters and standard meter (EC Response} was larger. Test meter measurements for the salinity by clay interaction were different than the standard meter by ±0.5, ±1, and -2.5 to +1.5 dS m-1, for EC levels of less than 3, 3 to 4, and greater than 4 dS m-1, respectively. The SenslON 5 handheld was the only meter tested that was not significantly different than the standard meter {p::; 0.48}. Test meter accuracy was highly dependent on temperature. Therefore, the most important criteria for selecting a portable meter for in-field EC measurements is the accuracy of the specific meter's temperature measurement and temperature compensation model.

Rights

NDSU policy 190.6.2

Rights Link

https://www.ndsu.edu/fileadmin/policy/190.pdf

Handle Identifier

https://hdl.handle.net/10365/33771

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