覆膜滴灌紫薯农田水热传输规律及其对环境因子的响应

农田水热传输过程的量化对于农业用水管理和作物灌溉制度的制定具有重要意义。本文利用波文比通量观测系统实测数据和气象站资料，对覆膜滴灌紫薯农田的水热通量变化规律及其对环境因子的响应进行了研究。结果表明：潜热通量是全生育期覆膜滴灌农田能量支出的主要部分，显热通量和土壤热通量支出占比较小，全生育期潜热通量、显热通量、土壤热通量支出占比分别为69.12%、25.14%、6.57%。不同天气条件下，显热通量的大小和变化范围均小于潜热通量。潜热通量对降雨和灌溉的响应最为显著，且降雨影响程度大于灌溉。净辐射、气温对潜热通量的影响较大，表层土温和风速变化的影响则较低，各环境因子主要通过直接和间接作用共同对潜热通量产生影响。该研究成果可以深化对覆膜滴灌紫薯农田水热传输规律的认识，为作物高效用水提供理论依据。

Water and Heat Transfer and Its Response to Environmental Factors in Drip Irrigated Purple Potato Field with Film Mulching

Drip irrigation with film mulching has been widely used in crop cultivation. Film mulching can change surface optical properties, including reflectance, absorption, and emissivity, which will affect the energy distribution in the farmland. It is necessary to study the water and heat transport and its influence factors in drip irrigated field with film mulching. The quantification of water and heat transfer process of the farmland is of great significance for agricultural water management and irrigation schedule formulation. Based on the measured data with Bowen ratio system and meteorological station, the water and heat flux variation and its response to environmental factors were studied in drip irrigated purple potato field with film mulching. The results indicated that latent heat flux was the main part of energy expenditure in drip irrigated purple potato field with film mulching during the whole growth period. Sensible heat flux and soil heat flux accounted for a relatively small proportion. During the whole growth period, the proportion of latent heat flux, sensible heat flux and soil heat flux was 69.12%, 25.14% and 6.57%, respectively. Under different weather conditions, the magnitude and range of sensible heat flux were smaller than that of latent heat flux. Latent heat flux had the most significant response to rainfall and irrigation. The influence of rainfall on latent heat flux was greater than that of irrigation. Net radiation and air temperature had great impact on latent heat flux, while the effects of surface soil temperature and wind speed had low impact. Various environmental factors affected the latent heat flux directly or indirectly. The research results can deepen the understanding of water and heat transfer in drip irrigated purple potato farmland under film mulching, and provide theoretical basis for efficient water use of crops.