Method for measuring mesoscale soil bulk density in field by using thermal pulse distributed optical fibers

The invention discloses a method for measuring mesoscale soil bulk density in a field by using thermal pulse distributed optical fibers, which comprises the following steps of: laying optical cables in the field, and burying the optical cables in to-be-measured soil with different soil layer depths; collecting temperature rise values along different spatial point locations of the optical fiber in the to-be-detected soil, and calculating to obtain the temperature rise values along the different spatial point locations of the optical fiber after noise reduction; calculating to obtain normalized accumulated temperature rise values of different spatial point locations along the optical fiber in the to-be-detected soil; establishing a function relationship between the soil moisture and the normalized accumulated temperature rise value, and obtaining the soil moisture of different spatial point locations along the optical fiber in the soil; the thermal conductivity of the soil is deduced according to the temperatur