With a couple of weekends full of rain and now intermittent snow nearly every day, the hot, dry summer may seem like a distant memory.

However, the effects of the dry weather are still being felt. Large-scale farmers with thousands of acres as well as gardeners with more modest plots to tend often take soil samples after the growing season to test the soil fertility. Normally, the time of year a soil sample is taken has very little effect on the results. Certain weather conditions, if drastic enough, do seem to skew soil test results. When soils are too wet or too dry for long periods of time it changes the form and availability of nutrients in the soil.

Potassium and pH are most likely to be affected by unusually wet or dry conditions.

Potassium is one of the three primary macronutrients taken up through the soil by higher plants along with nitrogen and phosphorus. Of the 13 nutrients taken from the soil by plants, the three primary macronutrients are needed in the largest amount. An inaccurate potassium test could become a serious problem.

Soil pH is the measure of soil acidity or alkalinity and is a factor in the availability of nutrients to plants. In some soils, dry conditions can result in lower test potassium levels due to potassium fixation between clay particles. The best way to know if the dry conditions affected your soil test is to compare this year’s results to the historical levels of the plot and the levels expected due to crop removal.

The Ohio State University Extension maintains soil test recommendations for critical levels and fertilizer recommendations for agronomic crops available at http://ohioline.osu.edu/e2567/index.html or contact the local OSU Extension office for more information.

Phil Myers is Ohio State University Agriculture and Natural Resources Extension educator for Clark County.