LEWISTON (AP) — Some farmers in northern Idaho and eastern Washington are looking for solutions after years of applying nitrogen-based fertilizer has left their land with acidic soil.
Carol McFarland with Washington State University told the Lewiston Tribune that soil surveys show a gradual increase in the acidity of soil in the region since the 1980s. Nitrogen-based fertilizer enriches the soil for some crops like wheat, but it can lower the natural pH of the soil, increasing the acidity level.
“There’s a certain degree of natural acidity in soil,” McFarland said. “However, on the Palouse, our previously near-neutral soils are being acidified by the application of nitrogen-based fertilizers.”
That can have an impact on some crops, like legumes, which are less tolerant of acidic soils. Lime can be applied to lower the acidity of the soil, but that can be expensive.
“It’s really tough for these guys to have enough on their (profit) margins to justify applying lime, so nobody really knows what the critical level is at this point,” she said, referring to what it would take to make the soil less acidic.
Some farmers who relied on legumes as a rotation crop are now experimenting with crops like triticale, she said.
“Different growers have been growing different things to work around the soil,” McFarland said.
But there is no one-size-fits-all remedy, because soils vary widely in the region, she said, depending on native vegetation, rainfall and other factors.
WSU will hold a daylong workshop on Jan. 4 with experts from WSU, the University of Idaho, the USDA and the Latah Soil and Water Conservation District to talk about the latest research and treatments for acidic soil. Preregistration is required, and tickets cost around $45, depending on payment method.
“This is a concern that’s on a lot of people’s minds. We really just want people to know about it and care about it so they can come and learn,” McFarland said.