Barbecho refers to "fallow land"—agricultural land left uncultivated for a period to restore its fertility. It's a word rooted in farming and rural life, making it quite unique in a song.
In "El Cerro Responde," the lyric "En lo barbecho del cerro" (In the fallow land of the hill) evokes a sense of hidden potential or a place where things are waiting to grow or be discovered. It hints at the humble beginnings or the overlooked spots where the protagonist's journey began, contrasting with his later success.
This song, "El Cerro Responde," tells a really interesting story about someone who started out poor and tried to make an honest living. He says, "no van a creer mis amigos y más pobre que usted" [my friends won't believe it, and poorer than you], talking about how he was even poorer than the listener. He tried to get ahead by working with the rich people in his town, hoping to succeed "en lo barbecho del cerro" [in the fallow land of the hill]. But it didn't work out. He realized that "jugar limpio no se puede" [you can't play fair] in the world he was living in.
So, he changed his ways! He decided to take a different path, and now things are very different. He's no longer thinking about the past; "ahora mi siempre son otras de lo vi antes ni me acuerdo" [now my always are others, I don't even remember what I saw before]. Instead of trying to earn money honestly, he's now driving a new car and dealing "pura mota a la barranca del Cerro" [pure weed to the ravine of the hill]. He's living a lavish life, with fancy clothes and expensive trucks, and he's got money to spend. He even mentions that "la policía ni los guachos hasta mi Araña la mano" [not even the police or the soldiers touch my hand]. It's a blunt look at how some people feel they have to turn to illegal activities to get ahead when the system seems rigged against them. The song ends with a bit of a cynical thought: "que al cabo va al cementerio puede llevar los millones trae Cerveza al dinero y acabó el cerro responde" [after all, you go to the cemetery, you can take the millions, bring beer to the money, and the hill responds].