A:   The nitrogen fertilizer can be applied any time over the next month. Plant uptake is relatively quick and the response is often visible as early as 1 week after application. A suggested rate is about 70 to 80 lb N per acre and you should easily see the response in greater production as long as there is adequate rainfall. Assuming 2,4-D will be the herbicide for annual broadleaf weed control; this can be applied after the oats is fully tillered, but before any stems begin to joint. Recommended rates are 0.25 to 0.50 ae/acre.