Canopy temperature monitoring soil water content based on field experiment of winter wheat

In the growth stage of winter wheat(from April to May in 2002),the canopy temperature,air temperature,volumetric soil water content were measured for the non-irrigation winter wheat.Beside,the canopy temperature,canopy-air temperature difference and volumetric soil water content are analyzed in this paper.The results indicate that the canopy temperature at 14:00 can reflect soil water content of the soil layen in 20 cm deep,but relativity in other soil levels has bigger fluctuation;the change of the volumetric soil water content in the depth 40 cm can be preferably reflected by the changes of canopy-air temperature difference at 14:00,the relational coefficients are 0.988 66(20 cm),0.993 89(40 cm),respectively which indicate that it can used as the base for monitoring regional soil water content through the retrieval regional canopy temperature; And during jointing stage and grain filling stage,the higher precision by canopy-air temperature difference simulating volumetric soil water content can be used as an empirical model for monitoring regional volumetric soil water content.