Abstract: Based on field experiments and using the temperature difference between canopy and air as well as the canopy temperature difference between wet and dry fields as main parameters, the models for soil moisture monitoring were established.According to the response of winter wheat, water diagnostic indices were also obtained. The study shows that canopy temperature difference between wet and dry fields can exclude the effect of atmosphere, and comparing with the temperature difference between canopy and air, it is a better of farmland water conditions.

Key words: Farmland ecosystem, Water condition, Canopy temperature, Winter wheat, water and carbon cycles, soil-vegetation-atmosphere continuum, stable isotope, water and carbon coupling