The Big Sandy Mountaineer -

MSU Extension and Chouteau County Conservation District Team Up to Measure Soil Acidity Across Chouteau County

MSU Extension and the Chouteau County Conservation District utilized the 2023 Soil Moisture Survey sites as a base sample survey for evaluating pH levels. While gathering soil moisture information, each of the 20 monitoring sites was measured for soil pH at the 2” and 6” soil depths. Samples were sent to Montana State University for testing. A special thanks to Jackson Bramlette from the Chouteau County Conservation District for helping collect samples and to Clain Jones (MSU Extension Soil Specialist) and Rosie Wallander (MSU-LRES Research Associate) for testing the samples.

The survey flagged a few points that should be noted by county producers. First, most of the soil textures at the sites are loams and clay loams which are typically less likely to be influenced by acidity. However, this has generally not been the case in Chouteau county. Based on this survey and samples collected since 2015, it appears that none of the cropland soil types are immune to increasing acidity. Secondly, 40% of the recorded sites noted soil pH’s below 6.0 at the 2” level. This can be a real concern when considering viable seed options for crop species and varieties as well as increased potential for signs of metal toxicity, i.e. aluminum and manganese. In addition, nodulation issues in pea occur below 5.8 pH and toxic levels for all crops result at 5.5 pH. Lastly, the problem appears to be wide spread. As a result, producers should continue to evaluate their soils at 2 inch and 6 inch levels. Areas of concern include the Highwood Bench, north of Great Falls just across the Chouteau County line, north of Carter near the Apple School Road, north of Fort Benton all the way to the Liberty County line, west of Geraldine and south of the Hopp School near Big Sandy.

For additional information on this emerging issue, go to http://landresources.montana.edu/soilfertility and click on Soil Scoops where you will find two documents on soil acidification. Please contact Clain Jones MSU Extension Soil Specialist (406-994-6076, or 622-3751) or Tyler Lane, MSU Extension Chouteau County (406-622-3751), if you have any questions.

Montana State University, U.S. Department of Agriculture and Montana Counties Cooperating MSU Extension is an equal opportunity/affirmative action provider of educational outreach. USDA and Conservation Districts are equal opportunity service providers and employers.