  We use \emph{Parker Solar Probe} (\emph{PSP}) in-situ measurements to analyze
the characteristics of solar wind turbulence during the first solar encounter
covering radial distances between $35.7R_\odot$ and $41.7R_\odot$. In our
analysis we isolate so-called switchback (SB) intervals (folded magnetic field
lines) from non-switchback (NSB) intervals, which mainly follow the Parker
spiral field. Using a technique based on conditioned correlation functions, we
estimate the power spectra of Elsasser, magnetic and bulk velocity fields
separately in the SB and NSB intervals. In comparing the turbulent energy
spectra of the two types of intervals, we find the following characteristics:
1) The decorrelation length of the backward-propagating Elsasser field $z^-$ is
larger in the NSB intervals than the one in the SB intervals; 2) the magnetic
power spectrum in SB intervals is steeper, with spectral index close to -5/3,
than in NSB intervals, which have a spectral index close to -3/2; 3) both SB
and NSB turbulence are imbalanced with NSB having the largest cross-helicity,
4) the residual energy is larger in the SB intervals than in NSB, and 5) the
analyzed fluctuations are dominated by Alfv\'enic fluctuations that are
propagating in the \emph{sunward} (\emph{anti-sunward}) direction for the SB
(NSB) turbulence. These observed features provide further evidence that the
switchbacks observed by \emph{PSP} are associated with folded magnetic field
lines giving insight into their turbulence nature.
