Late summer is a good time to check forage and row crop fields for possible nutritional problems and to make plans for fall soil sampling. "Problem" areas can be identified for selective sampling and the test results can be used to plan fertilizer and lime expenses for the next crop production season. Fields scheduled for tobacco, small grain and/or double cropping need to be sampled first in order to determine lime, phosphorus (P) and potassium (K) needs before fall application.
Grove, John H., "Soil Testing: Improving Reliability" (1984). Soil Science News and Views. 178.