Experimental warming alters soil hydro-thermal properties and heat flux in a winter wheat field

Abstract

ABSTRACTGlobal warming has profound effects on the distribution of water and heat in soil. This study aimed to examine the effects of warming on water storage, thermal properties, and heat flux changes at different depth (5–10, 10–20, and 20–40 cm) in a winter wheat (Triticum aestivum L.) field. The experiment with simulated warming, manipulated with infrared heaters, and its control combined with a nitrogen fertilization treatment was conducted in the North China Plain. The results showed that warming of around 2°C at 5 cm soil depth reduced soil water storage by 3.2%-11.1% before the jointing stage. However, the difference in soil water storage between warming and non-warming conditions behaved inversely before and after mid-April. Experimental warming significantly reduced soil volumetric heat capacity and thermal conductivity. In the winter, the warming depressed the upward heat flux by 42.4%-50.1% at the 5–10 cm layer, whereas the warming increased the downward heat flux by 5.5%-12.3% in the spring. Our observation indicates that the effects of warming on the exchange process of mass and energy between soil and the atmosphere should be further studied in agro-ecosystem regions.