Tall fescue accounts for the majority of our cool-season grass acreage. One-half to two-thirds of tall fescue's total annual growth occurs during April/May, far exceeding most producers' grazing capacity for that time. We commonly lose much of the spring hay crop due to poor haying conditions associated with wet weather. Placing more emphasis and inputs into fall production helps eliminate these spring problems. Many people feel cool-season grasses, especially tall fescue, provide inferior forage quality. Actually, the quality of tall fescue can be quite good. Cool-season grasses tend to have thinner cell walls compared to warm-season grasses like sorghum, corn or switchgrass. This leads to higher digestibility and crude protein levels but lower total energy compared to the warm-season grass species. In vitro dry matter digestibility (IVDMD) for tall fescue is generally superior with fall compared to spring growth.

A major advantage of tall fescue is its ability to be stockpiled for deferred grazing until late fall and throughout the winter. Its fall growth is vegetative and exhibits relatively low losses of forage digestibility and crude protein concentrations as it enters dormancy. Fescue leaves remain relatively green with high nonstructural carbohydrate concentrations into midwinter.

Tall fescue requires adequate fertilization, especially nitrogen, to provide good-quality forage. Many producers feel late winter/early spring applied nutrients will cycle and be available to fescue plants throughout the entire year. This philosophy does not follow good agronomic principles. Due to losses (such as luxury plant consumption, crop/animal removal, leaching, runoff and denitrification) it is unreasonable to assume fertilizer applied in the spring is still available for tall fescue fall growth. Hayed fields have removed considerably more nutrients than pastured fields and will need more late-summer nutrient additions. Regardless of usage, by not fertilizing in late summer or early fall, you are sacrificing fall growth, yield and forage quality. All tall fescue pastures used for fall/winter grazing should receive plant nutrients, especially nitrogen, between Aug. 15 and Sept. 15. Phosphorus and potassium applied in late summer enhance stand persistence and winter hardiness. Given the growth habit, quality characteristics, nutrient cycling and stockpiling ability of tall fescue, why would anyone want to apply 100 percent of its annual fertilization in the late winter/early spring?

This spring was not favorable to producing or utilizing cool-season grass pasture and hay fields. Several reasons such as early drought, late, heavy rains that disrupted hay harvest and severe armyworm infestation led to decreased tall fescue forage production this year. Without increased fall production, you can expect to have low-quantity and/or extremely poor-quality forage going into this winter.

How should you apply fall plant nutrients to tall fescue growing in combination with legumes such as clover, lespedeza, alfalfa or birdsfoot trefoil? Contrary to popular belief, legumes do not directly feed nitrogen to grasses. The quantity of nitrogen available from a legume is almost always less than that required for maximum grass production. Effective transfer of nitrogen from legume to grass occurs primarily through legume residue decomposition and animal grazing redistribution. Legumes have a competitive advantage over grasses in low nitrogen environments. Conversely, grasses have a competitive advantage in low phosphorus and potassium soils because of a fibrous root system that produces greater root surface and nutrient-extracting capabilities than the taproot system of legumes. If your stand contains less than one-third of its total biomass as legumes, apply 40 to 60 pounds of nitrogen per acre later this month. It is easy to overestimate the percentage of a stand that is composed of legume material. Generally, 10 percent red clover by weight visibly appears to represent 50 percent of a pasture. Of the hundreds of grass/legume pastures I have walked, a small percentage have contained greater than one-third biomass legume.

Unlike with nitrogen, many agronomists feel tall fescue only needs to be fertilized with phosphorus and potassium once annually. In principle, I would agree. However, when you plan for two nitrogen applications per year, it is convenient to apply some phosphorus and potassium with each application. I feel the split application is beneficial for overwintering and to avoid luxury consumption of these nutrients. Regardless of application timing, total annual phosphorus, potassium and other nutrient recommendations should be based on soil test results. This is the only accurate way to manage these nutrients.