Appropriate use of crop rotation and natural fertilizer (cow manure is quite effective) can significantly reduce the amount of fertilizer needed. I don't think

Appropriate use of crop rotation and natural fertilizer (cow manure is quite effective) can significantly reduce the amount of fertilizer needed. I don't think we ever put artificial fertilizer on our fields, just spread on some cow dung. In any sort of farming operation, soil nutrients MUST be replenished. A huge industrial farm can practice crop rotation at least as well as a small farmer, if not better, and of course can afford to have employees devoted specifically to managing and planning fertilizer application when needed. Farming can be an expensive proposition--it is not cost-effective to apply pesticides/herbicides/fertilizer when not needed!