• 한국토양비료학회지
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• 제50권5호
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• pp.336-344
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• 2017

The soil water characteristics curve (SWCC) represents the relation between soil water potential and soil water content. The shape and range of SWCC according to the relation could vary depending on soil characteristics. The objective of the study was to estimate SWCC depending on soil types and layers and to analyze the trend among them. To accomplish this goal, the unsaturated three soils were considered: silty clay loam, loam, and sandy loam soils. Weighable lysimeters were used for exactly measuring soil water content and soil water potential. Two fitting models, van Genuchten and Campbell, were applied. Two models entirely fitted well the measured SWCC, indicating low RMSE and high $R^2$ values. However, the large difference between the measured and the estimated was found at the 30 cm layer of the silty clay loam soil, and the gap was wider as soil water potential increased. In addition, the non-linear decrease of soil water content according to the increase of soil water potential tended to be more distinct in the sandy loam soil and at the 10 cm layer than in the silty clay loam soil and at the lower layers. These might be seen due to the various factors such as not only pore size distribution, but also cracks by high clay content and plow pan layers by compaction. This study clearly showed difficulty in the estimation of SWCC by such kind of factors.

• 한국토양비료학회지
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• 제49권4호
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• pp.300-309
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• 2016

The monolithic weighing lysimeter is a useful facility that could directly measure water movement via layers, drainage, and evapotranspiration (ET) with precise sensors. We evaluated water movement through layers and water balance using the lysimeter with undisturbed paddy sandy loam soil, Gangseo soil series (mesic family of Anthraquic Eutrudepts classified by Soil Taxonomy) during winter season from Dec. 2014 to Feb. 2015. Daily ET indicated up to 1.5 mm in December and January and 2 mm in February. The abrupt increase of soil water tension at the depth of 0.1 m, when soil temperature at the same depth was below $2^{\circ}C$, was observed due to temporary frost heaving. The surface evaporation was less than reference ET below -15 kPa of soil water potential at the depth of 0.1 m. The maximum drainage rate was similar to the saturated hydraulic conductivity of a plow pan layer. Both upward and downward water movement, related to ET and drainage, were retarded by a plow pan layer. This study demonstrated that the lysimeter study could well quantify water balance components even under frost heaving during winter season and that a plow pan with low permeability could act as a boundary that affects drainage and evapotranspiration.

• 한국농림기상학회지
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• 제22권3호
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• pp.205-214
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• 2020

본 연구에서는 중량식 라이시미터를 이용하여 토양 및 물관리 방법에 따라 배추와 옥수수 재배기간 동안 물수지를 평가하였으며, 작물 생산성과 물 부족 상황을 고려하여 작물 수분스트레스 계수와 최소 물 필요량을 산정하였다. 2018 년 배추 재배는 정식 2 주 후 빈번한 강우로 인해 관개가 실시되지 않아 무관개구와 적습관개구의 관개량 차이가 없었으며, 생산량 차이 또한 나타나지 않았다. 2018 년 배추 재배를 제외하고 배추와 옥수수 재배에서 적습관개구가 무관개구보다 생산량이 높게 나타났으며 대체적으로 증발산량 또한 높게 나타났다. 생산량과 증발산량은 밀접한 관련이 있으며 바이오매스 증가에 따라 증산작용이 활발해짐을 알 수 있었다. 작물 수분스트레스 계수는 배추 중기 0.8, 후기 0.8, 옥수수 중기 0.8, 후기 0.5 로 산정되었다. 배추와 옥수수의 최소 물 필요량(2017 년 배추 196.2 mm, 2018 년 옥수수 321.0 mm)은 적정 물 필요량(배추 239.4 mm, 2018 년 옥수수 466.9 mm) 대비 각각 82.0%, 68.8% 수준으로 나타났다. 이러한 산정 결과는 물부족 시기에 최소 관수량을 확보하여 작물 재배를 위한 물관리의 기초자료로 활용할 수 있을 것으로 생각된다.