- Fertilizer is cheaper than buying more land and should, depending on the weather, increase your carrying capacity. By how much is very site and rainfall dependent

- Fertilize to a soil test makes more economic sense than just throwing fertilizer on grass

- I've been told it is best to spread fertilizer AFTER the first flush of spring growth which can often come on too fast and lush anyway. Around here fertilizing pastures near the end of May, after first hay cutting or first grazing, is recommended by the UW. 2nd and later grazings or hay cuttings really benefit from fertilization with N. Late May around here is still early enough that getting good rain on it is likely.