Kalibracija merilca vsebnosti vode v izbranih tleh

Hren, Urška (author), Pintar, Marina (mentor), Kastelec, Damijana (comentor)

TRIME-PICO32 so merilniki volumske vsebnosti vode v tleh, ki delujejo na osnovi meritev relativne dielektričnosti tal, ki spada med posredne metode meritev vsebnosti vode v tleh. Pri uporabi na terenu, v Dekanih nad Koprom in Biljah v Vipavski dolini, se je izkazalo, da zaradi umanjkanja talno specifične kalibracije merilniki kažejo nezanesljive podatke. Obema lokacijama je skupno, da tla vsebujejo visok delež skeleta. Namen dela je bil ovrednotiti kalibracijo merilnikov za vsakega od obeh tipov tal pri dveh različnih volumnih oz. premerih (7 in 15 cm) neporušenih in porušenih vzorcev tal ter ugotoviti, kakšen je vpliv skeleta na delovanje merilnikov. Predvidevali smo, da je primernejša kalibracija pri manjšem premeru in v porušenem vzorcu (tj. kjer je bil odstranjen skelet) tal. Na obeh lokaciji smo odvzeli po 12 neporušenih talnih vzorcev (po šest s cilindri premera 7 in 15 cm) in ustrezno količino tal za vzpostavitev enakega števila porušenih vzorcev obeh premerov v laboratoriju. Za kalibracijo merilnikov smo uporabili gravimetrično metodo določanja vsebnosti vode v tleh. Z linearnim modelom smo ovrednotili razlike med gravimetrično in z merilnikom izmerjeno vsebnostjo vode v tleh pri različnih obravnavanjih. Ugotovili smo, da se napake meritev manjšajo s sušenjem tal ter da so v Dekanih merilniki bolj usklajeni v vzorcih s premerom 15 cm, v Biljah pa v porušenih vzorcih.

• Language: Slovenian
• Keywords: voda v tleh, volumski delež vode, merilne naprave, TDR, gravimetrična metoda
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [U. Hren]
• Year: 2021
• PID: 20.500.12556/RUL-125948
• UDC: 631.423.2:681.12:621.713(043.2)
• COBISS.SI-ID: 59077123
• Publication date in RUL: 10.04.2021

Secondary language

• Language: English
• Title: Calibration of a soil moisture sensor in selected soils

Abstract

TRIME-PICO32 is a sensor for soil water content measurements. It operates on the basis of measuring soil relative permittivity, which is an indirect method for measuring soil water content. Used in the field in Dekani nad Koprom or in Bilje in the Vipavska dolina valley, the sensor proved to be indicating unreliable data due to the lack of soil-specific calibration, as both locations contain a high level of skeleton. The objective of this thesis was to evaluate sensor calibration for each of the two soil types at two different volumes or diameters (7 and 15 cm) of undisturbed and disturbed samples and to determine the influence of the skeleton on the operation of sensors. The hypothesis set was that more appropriate calibration appears in the case of a smaller diameter and of disturbed samples (that is of removed skeleton) of soil. At both locations 12 undisturbed samples of soil were taken (six of each, with diameters of 7 and 15 cm) and an appropriate amount of soil to determine the same amount of disturbed samples of both diameters in the lab. For calibration was used the gravimetric method for determining the soil water content. The evaluation of the differences between the gravimetrical and sensor-measured soil water content in different surveys was carried out using the linear model. The results showed that measurement errors decrease in case of dried soil; in Dekani the sensors proved to be more synchronised when measuring the samples with a diameter of 15 cm whereas in Bilje, the same was the case when measuring disturbed samples.

• Keywords: soil water, volumetric water content, measurement devices, TDR, gravimetrical method