Investigation of the Effect Soil particles size on the Currency Time Domain Reflectometry for water content measurement
الموضوعات :عیسی معروف پور 1 , مینا بهزادی نسب 2
1 - دانشگاه کردستان، گروه مهندسی آب، کردستان، ایران.
2 - شرکت آب منطقهای کردستان،کردستان، ایران.
الکلمات المفتاحية: Calibration, بافت خاک, TDR, Soil texture, کالیبراسیون,
ملخص المقالة :
This study carried out on the provided textures at laboratory. The provided textures were infusedinside the PVC cylinder with 30cm height and 25cm diameter. The studied textures were loamysand, sandy loam, sandy clay-loam, clay loam and clay. After 24 hours of saturation, the soil watercontent of the samples was measured by oven-dry gravimetric and TDR methods. For each texturesat any stage of measurement the determination of moisture and di-electric constant were done atthree capture windows and with three repetitions. In each day the moisture measurement of eachtexture was carried out by these two methods until a moisture range was determined. The results ofthis research show that: 1- For all soil textures the measured moisture at the capture windows of 20ns has more accuracy compared to the other capture windows. and TDR device can not measure thesoil water content at capture window of 40 ns. 2- For loamy-sand and sandy-loam textures when themoisture was less than 20% and also for other textures for total range of measurement, the TDRdevice measured the moisture values less than the gravimetric method. This difference is increasedwhen the soil ranged from light to heavy textures. 3- From the statistical view at probably level of1% there is not difference between the measured value of moisture by TDR device and gravimetricmethod. 4- For the all textures the fitted regression lines have high regression coefficient.
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