I Farmed Some Land in the Song Dynasty

[Traveling through the Song Dynasty + system missions + farming business + resisting Jin soldiers + multiple female characters + decisive killing] The protagonist owes tens of billions in debt on the earth star, and is selected by the system. He travels through the Song Dynasty and uses modern technology to hoard land for farming, and becomes a veritable super landowner. He is so powerful that even the emperor begs him to send troops to protect the country...