Question about farming practices

hello everyone! i have a question about kashrut in relation to farming, and probably a bit of a silly question to have gnawing at my brain.

throughout various places, different things have been used as fertilizer for crops. in medieval Ireland for example, many coastal regions used shellfish since it was readily available and worked well. do certain kinds of fertilizers effect the kosher status of the food being grown? if so, is there a way to ammend the now non-kosher food item in the same vein as kashering a stove, or was the solution just not using a particular kind of fertilizer?

thanks in advance!