Thank you, Joshua Branson!
Your code helped me a bit

(use-modules  (gnu services databases) )
(services (cons*  (service postgresql-service-type)
%desktop-services))

After `guix reconfigure /etc/config.scm` and reboot postgresql server is running:
# herd status | grep postgre
 + postgres

The only one change I want to do. Please, how to disable auto-start of postgresql? I need it sometimes and want to start it manually only. I think there should be some guile function like '(service postgresql-service-type (config no-autostart))', but qwant search does not give the answer. 
I've read 'start' and 'stop' options here https://www.gnu.org/software/guix/manual/en/guix.html#Shepherd-Services <https://www.gnu.org/software/guix/manual/en/guix.html#Shepherd-Services> 
and here
https://www.gnu.org/software/shepherd/manual/shepherd.html#index-Configuration-file <https://www.gnu.org/software/shepherd/manual/shepherd.html#index-Configuration-file>
 and tried to find out here http://git.savannah.gnu.org/cgit/guix.git/tree/gnu/services/databases.scm <http://git.savannah.gnu.org/cgit/guix.git/tree/gnu/services/databases.scm>
But I did not get the answer for those 10 minutes I've spend there.
I tried with no success:
(service postgresql-service-type (unstartable '()) )
(service postgresql-service-type (config (unstartable '()) )(service postgresql-service-type (let (unstartable '())) )

Please, how to do this?