With planting season underway and fertilizer costs rising amid the war in Iran, an Iowa farmer is urging Congress to use the next farm bill to reduce growers' dependence on volatile inputs. The warning points towards farmers' dependence on fertilizers and pushes a move towards regenerative agriculture. What's happening? In an op-ed for Civil Eats, Iowa farmer Wendy Johnson connected the fertilizer pricing shock with memories of the 1980s Farm C…