Sowing

In Serbia in the past people lived in extended families called "zadruga". When grain needed to be sown, the family would choose one man to do all the sowing. He had to abstain from sex from that moment until all the seeds were sown. 

Sowing (spreading of seeds) is here directly linked with ejaculation (spreading of semen). Male reproductive energy which is usually used to impregnate a woman has to be during sowing period preserved and used to impregnate the Earth... 

Once a man finished sowing grain seeds, it was female fertile energy of the "Mother Earth" which then turned each grain seed into a grain plant full of new grain seeds...Slavs believed that this fertile energy was taken away from the "Mother Earth" when the grain was harvested...

So, in the past in Russia, after the last sheaf of grain was cut, women harvesters would lie down on the ground and roll around the field "to return the strength to the earth"...

These Slavic harvest customs directly link female fertility with "mother earth" and male fertility with "father sky", who "fertilises mother earth with his semen, rain"...

You can find loads of stuff related to agricultural "magic", customs, folklore, beliefs in my twitter threads and in my blog posts, like these ones: "Diduch", "Wheat wreath", "Walking sheafs of wheat", "Catching rooster", "Partridge"