Oh indeed, that rain is semen is the biblical view. Walter C. Kaiser, History of Israel: "the rainfall that refreshed the ground was thought to represent Baal's semen falling to the earth to fertilize the ground…"
What God does to the earth in Genesis 1 might be an image of impregnation. A key text of the Dead Sea Scrolls says of human creation: "he is spat saliva, moulded clay, and for dust is his longing."
This may be the image behind Jesus spitting to make mud in John 9:6.
As all water seems to be divine ejaculate ("living water"), spit seems to have reference to semen.
As always in the Bible, God is "male" and earth is "female." So the spit and dust together create a life form.