It ' s a complex issue , because most of the US has access to practically infinite amounts of fertilizer and ultra cheap water even states with water shortage provide their agricultural sector with water so cheap it ' s basically free . But if you argue from a stand point of waterfertilizer scarcity i . e . an arid 3 rd world country , growing a crops like millet is far superior to corn probably in all metrics calories per acre , calories per liter water , calories per dollar spent on fertilizer . Now , if you ' re a conservationist or from California and pissed about the water situation , you might have an interest in minimizing things like fertilizer wash off , pH balance of your aquifers , lakes and streams or just overall water usage in agriculture . but I fully realize most people especially farmers just aren ' t .