Two-dimensional wave turbulence on the charged surface of liquid hydrogen in a rectangular cell has been studied. It has been found that, after intense monochromatic pumping at frequencies of 14–30 Hz in an electric field partially compensating the gravitational field of the Earth, incommensurate subharmonics at low frequencies until 0.8 Hz can be observed on the surface of the liquid with a certain time delay in addition to the direct turbulent cascade of Kolmogorov-Zakharov capillary waves. The nonlinear interaction of these subharmonics with each other and with a wave excited at the pump frequency results in the appearance of additional combination waves in the direct turbulence spectrum.