EVAPORATION MEASUREMENTS AND PREDICTIONS FROM SOILS UNDER CROP CANOPIES
EVAPORATION MEASUREMENTS AND PREDICTIONS FROM SOILS UNDER CROP CANOPIES
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DOI：
10.13031/2013.31512
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发表时间：
1990
影响因子：
1.5
通讯作者：
N. L. Klocke;D. L. Martin;R. Todd;D. L. DeHaan;A. Polymenopoulos
中科院分区：
文献类型：
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作者：
N. L. Klocke;D. L. Martin;R. Todd;D. L. DeHaan;A. Polymenopoulos
本文采用两种不同尺寸的蒸渗仪测定了日蒸发速率：（1）内径15 cm的小型蒸渗仪;（3）内径7.6cm的微型蒸渗仪。6厘米长。实地研究在内布拉斯加州中西部的半干旱气候和内布拉斯加州东部的半湿润气候中进行。试验土壤为粉壤土、细砂和粉质粘壤土。作物根被排除在蒸渗仪之外。每天在田间小区用土壤重新填充微蒸渗仪。第二天，他们测量了蒸发量。由于微型蒸渗仪最接近匹配的领域土壤水分，他们测得的蒸发速率提供验证的迷你蒸渗仪，这是充满了未受干扰的土壤，每个季节一次。在小型蒸渗仪的土壤水分含量匹配到周围的田间土壤主要湿润事件后，然而，小型蒸渗仪变得比周围的土壤，这是受作物的水提取更湿。对于喷灌玉米与全冠层覆盖的土壤，蒸发速率从微型蒸渗仪平均0.2毫米/天以上的微型蒸渗仪。从迷你蒸渗仪的蒸发速率进行了比较，从两个能量为基础的模型相结合的预测。里奇（1972）模型计算了作物冠层下土壤表面的净辐射。Idso（1979年）的模型利用这些信息加上空气和土壤表面温度来预测蒸发。没有对模型组件进行任何现场校准。Idso的模型需要进一步校准，以涵盖本研究中的土壤范围。在密集遮荫下，土壤表面的净辐射值较低，这可能导致这些模式对蒸发的预测不足。
ABSTRACT Daily evaporation rates were measured with two sizes of lysimeters: (1) mini-lysimeters, 15 cm Inside Diameter (I.D.) and 20 cm long; and (3) micro-lysimeters 7.6 cm I.D. and 6 cm long. The field studies were conducted in the semi-arid climate of west central Nebraska and the sub-humid climate of eastern Nebraska. Silt loam, fine sand, and silty clay loam soils were used in the experiment. Crop roots were excluded from the lysimeters. The micro-lysimeters were refilled daily with soil in the field plot. The following day they measured evaporation. Since the micro-lysimeters most closely matched the field soil water, their measured evaporation rates provided validation for the mini-lysimeters, which were filled with undisturbed soil once each season. Soil water contents in the mini-lysimeters were matched to the surrounding field soil after major wetting events; however, the mini-lysimeters became wetter than the surrounding soil which was subject to water extraction by crops. For sprinkler irrigated com with full canopy cover of the soil, the evaporation rates from the mini-lysimeters averaged 0.2 mm/da more than the micro-lysimeters. Evaporation rates from the mini-lysimeters were compared with predictions from the combination of two energy based models. The Ritchie (1972) model calculated the net radiation at the soil surface under a crop canopy. The Idso (1979) model took this information plus air and soil surface temperatures to predict evaporation. There wasn't any on-site calibration of the model components. Idso's model would need further calibration to cover the range of soils in this study. The low values for net radiation at the soil surface under dense shading may lead to under prediction of evaporation from these models.