Late fall can be a good time to apply fertilizer and lime to pastures. Make sure that weather conditions are right, mainly that soil is not getting compacted or ruts created during the application of lime or fertilizer. Pasture fertility is complicated by the fact that grazing livestock move and transfer nutrients. This will result in pockets of higher or lower fertility compared to average pasture values. For this reason, applications of fertilizer and lime to pastures should be based on good soil sampling procedures.
Grid soil sampling might be used to identify low, average and high fertility areas within a pasture. This would allow fertilizer and lime application to be targeted to where it is most needed and avoid over and under application when a recommendation is based on one single average sample. This procedure might be mimicked by the observant pasture manager sampling according to pasture productivity and livestock grazing patterns.
Once soil test results are in hand, a pasture fertility goal might be to apply limestone and fertilizer to meet minimum or critical soil test levels. For grass/legume pastures, I generally recommend the following soil test goals: soil pH of 6.5, soil phosphorus level of 25 parts per million (ppm) and soil potassium level of 100 to 110 ppm. Once these critical values have been reached, the goal might be to maintain or increase pasture fertility through good grazing management.
If a choice must be made between fertilizer and limestone, putting dollars into increasing the soil pH is probably the wisest use of dollars. Getting soil pH to 6.5 or close to it allows the availability of other nutrients in the soil to be maximized. Various sources recommend that urea nitrogen fertilizer should not be applied for up to one year after lime has been surfaced applied.
When the question of nitrogen fertilizer is raised, we must think about the nitrogen source, weather forecast, and soil temperature. If the goal of the producer in applying nitrogen fertilizer is to produce grass growth for livestock grazing, then the benefit from a late fall application (November) is very limited. Our cool season grasses grow best in an air temperature range of 55 to 75 degrees F. How many of these days can we count on in November? There can be some slower grass growth, particularly with tall fescue, even in the 40 to 45 degree range, but even so, the amount of dry matter accumulation will not be very great.
The main benefit of applying a nitrogen fertilizer in November is to strengthen that grass plant for the coming year. Even though the air temperature is too cold for above ground growth, the soil temperature is warm enough for root growth. Late fall nitrogen fertilization feeds the plant roots, allowing the plant to build a stronger root and tiller system. Grasses fertilized in the late fall will green up quicker in the spring and produce more vigorous growth.
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