The ground is not frozen yet, which means growers and agronomists still have an opportunity to take fall soil samples. This is one of the best times to sample because…
—For results to be as close as possible to the situation next spring, the ideal time to take fall samples is when soil temperatures drop below 10°C and as close to freeze-up as possible. Microbial processes in the soil slow down as temperatures cool, so mineralization should be minimal below that threshold.
—And with results and recommendations in hand before winter, growers can use the winter months to plan their fertilizer programs for next year, to order fertilizer, and to take advantage of reduced pricing opportunities that may occur. Growers and agronomists can also use these results to review practices in 2015 and adjust practices, if necessary, for 2016.
Producers may not want to test all fields, so perhaps just pick a few to use as benchmarks. Fields with mediocre results may be a good place to start because soil reserves left may be harder to predict. Sometimes lower yield is the result of low nutrient availability, but often some other stress — such as too much or too little moisture, or disease — caused the mediocre yields. In these cases, soil nutrient reserves may be higher than expected. Testing one higher-yielding field also provide a chance to compare soil reserves and nutrient recommendations to the mediocre-yielding fields.