Liming is not a routine practice in North Dakota as it is in many areas of the eastern Corn Belt. Most soils in North Dakota have a pH higher than 6.0 which do not generally require liming to raise the soil pH. Zone soil sampling, which breaks fields into several areas for variable rate nutrient application is revealing many areas of fields with very low pH, even in eastern North Dakota.
We recently discovered an area of very low soil pH in a field just a few miles from our laboratory in Northwood ND. The topsoil pH was 4.8 and the subsoil pH less than 6.0! This low pH area in the field is over 20 acres and is certainly big enough to consider for a lime application. This spring we applied three rates of lime to a demonstration project in this field. We used spent beet lime as it is available locally at no charge in areas where there is sugarbeet production. Sugarbeet lime has an ENP (effective neutralizing power) of about 80.
Three rates of lime were applied and tilled into the soil (see figure). Soybeans were planted on this field late this spring. Even though the lime has only been applied for five months, the soil pH has already increased on all of the treatments as shown in the table. This demonstration project will be a long term project as we measure the effects of the lime application on the soil pH and on the growth of subsequent crops on these areas for several years. Liming may become a routine practice in parts of fields effected by very low soil pH. Zone soil sampling is a tool which will help reveal areas which may require lime to reach top yield potential.