Select a brush of grass shape from the standard set of brushes and two different green nuances to insert the grass along the lowest edge of the wallpapers.



Make it darker a little with Image ? Adjustments ? Hue/Saturation (ctrl+u).



Decolorize the grass' upper part on a new layer, using the usual Gradient Tool.



Change the layer's Blending Mode on Soft Light.



Then we have to create a new layer under the sun's layer and set the next shown Gradient Tool's adjustments, selecting the colors of the stripes by pressing Randomize button.



Create a kind of stretching, coming from the sun's central part and then make the layer look totally white with the Channel Mixer option.



Minimize after that the quantity of the stripes and represent one more new layer to paint it out under a different angle this time.