日光温室作物冠层下表层土壤温湿度分布特征研究及数值模拟

Research and Numerical Simulation on Distribution Characteristics of Soil Surface Temperature and Humidity under Crop Canopy in Solar Greenhouse

日光温室室内土壤温湿度是影响作物生产的主要因素。本研究以日光温室室内土壤为研究对象,通过测取温湿度及数值模拟,分析研究了不同高度作物冠层下土壤温湿度的分布特征。研究发现,随着冠层高度的增加,日间土壤温度下降时间出现滞后现象,1.0 m冠层比0.8 m冠层下土壤温度下降时间延迟了1 h,土壤含水率日变化波动变小。当作物形成冠层时,日间冠层顶部中间区域温度最高,冠层底部的温度呈现“南高、北低”的分布趋势,表层土壤与冠层底部温湿度空间分布趋势一致。利用CFD方法对日光温室作物冠层区域和表层土壤进行模拟研究,模拟结果与实测结果对比,误差较小,模型有效可行。该数值模型可以有效地表征作物冠层及冠层下表层土壤的温度分布。

The indoor soil temperature and humidity are the main factors affecting the crop production in the solar greenhouse.The indoor soil of the solar greenhouse was taken as the research object.The distribution characteristics of the soil temperature and humidity at different heights canopy of crops were analyzed and studied via experiments and numerical simulation.It was found that with the increase of canopy height,the time of daytime soil temperature decline was delayed,and the time of soil temperature decline in the 1.0 m canopy was 1 hour later than that in the 0.8 m canopy.The daily fluctuation of soil moisture content became smaller.When crops formed a canopy,the temperature in the middle area at the top of the canopy was the highest in the daytime,and the temperature at the bottom of the canopy showed a distribution trend of high in the south and low in the north.The spatial distribution trend of the temperature and humidity in soil surface and canopy bottom was consistent.The CFD method was used to simulate the temperature of crop canopy area and soil surface in the solar greenhouse.The comparison between the simulation values and the measured results showed that the error was small,indicating the model was effective and feasible.This numerical model could effectively characterize the temperature distribution of the crop canopy and the soil surface layer under the canopy.