Farm406

farm406 40 Over the years soil analysis, along with crop selection, has become more sophisticated. Now soil is chemically tested for its pH level and identified as acidic, neutral, or alkaline (containing lime). Homesteaders were fortunate because most Montana soils were originally neutral to alkaline, and crop selection had lile to do with the soil pH level, but that is no longer the situation. Montana farmers are starting to see crop failure, and the traditional remedies for low soil nutrients or diseases aren't helping. One major cause of the poor crop growth is low soil pH, and the problem is likely to increase. When homesteaders, their children, and grandchildren realized that winter wheat grew especially well in the arid climate where much of the moisture occurred in the winter and early spring, the state became almost a wheat monoculture. Boosting bushels per acre was achieved by increasing nitrogen-high ammonium-based fertilizers, including urea, but it also has caused acidification in some fields. Acidification happens regardless of the Nitrogen rate, but it occurs at a faster rate when Nitrogen is applied beyond what is taken up by the plants. Clain Jones, soil fertility specialist with MSU Extension and a professor in the MSU College of Agriculture's Department of Land Resources and Environmental Sciences, said that "soils tend to become more acidic fairly quickly, even with the recommended levels of fertilizer use." Once pH is below 6, legumes have a hard time fixing their own nitrogen, and below pH 5, many traditional crops have a hard time growing. Recognizing Encroaching Soil Acidity Farmers, especially in North Central Montana, are seeing patches in their fields where plants fail to germinate. ose that sprout have a yellow or a purple cast to the leaves, and they are smaller than plants in the rest of the field. e roots of unhealthy plants are broom shaped with club ends, and the there are few nodules on legume roots where microbes 'fix' nitrogen. e nodules are brown rather than white with a pink center. ese unproductive patches of ground seem to spread outward every year. To be sure, farmers recognize that this is a problem that cuts into their profits, and interest in finding the cause and cure is high. Reason for Increased Soil Acidity What to Do about Soil Acidity Jones has framed solutions to the soil acidity problem with the word MAP that stands for mitigate—by taking proactive measures to correct the problem, adapt—recognizing the problem by modifying farming methods, or prevent— changing farming practices in fields that don't have acidity problems yet. Photo: Hardy O'Hara

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