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首页> 外文期刊>Transactions of the ASABE >Comparison and analysis of empirical equations for soil heat flux for different cropping systems and irrigation methods.
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Comparison and analysis of empirical equations for soil heat flux for different cropping systems and irrigation methods.

机译：不同耕作制度和灌溉方式下土壤热通量经验公式的比较和分析。

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We evaluated the performance of four models for estimating soil heat flux density (G) in maize (Zea mays L.) and soybean (Glycine max L.) fields under different irrigation methods (center-pivot irrigated fields at Mead, Nebraska, and subsurface drip irrigated field at Clay Center, Nebraska) and rainfed conditions at Mead. The model estimates were compared against measurements made during growing seasons of 2003, 2004, and 2005 at Mead and during 2005, 2006, and 2007 at Clay Center. We observed a strong relationship between the G and net radiation (Rn) ratio (G/Rn) and the normalized difference vegetation index (NDVI). When a significant portion of the ground was bare soil, G/Rn ranged from 0.15 to 0.30 and decreased with increasing NDVI. In contrast to the NDVI progression, the G/Rn ratio decreased with crop growth and development. The G/Rn ratio for subsurface drip irrigated crops was smaller than for the center-pivot irrigated crops. The seasonal average G was 13.1%, 15.2%, 10.9%, and 12.8% of Rn for irrigated maize, rainfed maize, irrigated soybean, and rainfed soybean, respectively. Statistical analyses of the performance of the four models showed a wide range of variation in G estimation. The root mean square error (RMSE) of predictions ranged from 15 to 81.3 W m-2. Based on the wide range of RMSE, it is recommended that local calibration of the models should be carried out for remote estimation of soil heat flux.
机译：我们评估了四种模型在不同灌溉条件下估算玉米（Zea mays L.）和大豆（Glycine max L）的土壤热通量密度（G）的性能。方法（内布拉斯加州米德的中心枢轴灌溉田和内布拉斯加州克莱中心的地下滴灌田）和米德雨育条件。将模型估计值与在Mead的2003、2004和2005生长季节以及在Clay Center的2005、2006和2007年进行的测量值进行比较。我们观察到G与净辐射（R n ）之比（G / R n ）与归一化植被指数（NDVI）之间存在很强的关系。当大部分土壤是裸露土壤时，G / R / n> n 在0.15到0.30之间，并且随着NDVI的增加而降低。与NDVI相比，G / R n 比随作物的生长和发育而降低。地下滴灌作物的G / R n 比小于中枢轴灌溉作物。灌溉玉米，雨育玉米，灌溉大豆和雨育大豆的季节平均G分别为R 的13.1％，15.2％，10.9％和12.8％。对这四个模型的性能进行统计分析表明，G估计值的变化范围很大。预测的均方根误差（RMSE）为15至81.3 W m -2 。基于RMSE的广泛范围，建议对模型进行局部校准以远程估算土壤热通量。

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