Pastures: Annual Forages for Pasture
Forage brassicas are high-yielding, high-quality, fast-growing annual crops. They are used primarily for grazing livestock and dairy animals. They are quick to germinate, and when seeded in the spring provide a hedge against summer drought. They fit well between crop rotations to provide forage in late summer or late fall. For more detailed information, refer to Agronomy Facts 33: Use of Brassica Crops to Extend the Grazing Season, available from your local extension office.
Rape is a short-season, leafy brassica whose stems and leaves are eaten by the grazing animal. It can also be green-chopped. Rape regrows after harvest. Many varieties have been tested in Pennsylvania. Rangi, Windall, Dwarf Essex, Winfred, and Emerald have been shown to perform satisfactorily.
Turnips are short-season, root brassica whose roots, stems, and leaves are used. Regrows after harvest. Purple Top, Forage Star, and Green Globe have been tested and shown to perform satisfactorily in Pennsylvania.
Kale is a long-season, leafy brassica whose stems and leaves are used. Recent studies in Pennsylvania have shown that Marrow Stem, Maris Kestral, and Premier show promise. Kale does not regrow after harvest, with the exception of Premier, which does regrow.
Swede is a long-season root brassica whose roots, stems, and leaves are used. Calder has been found to be the most frost-tolerant of all brassicas tested in Pennsylvania. Swede does not regrow after harvest.
Typhon, a Chinese cabbage-turnip hybrid, performs best under a multiharvest system.
Determine lime and fertilizer needs by soil test. In the absence of a soil test, apply 75-60-60 per acre. Brassicas require nitrogen, which should be applied at time of seeding.
Brassicas grow best in moderately to well-drained soils. Brassica crops commonly are seeded at corn planting time for late summer grazing or in August for fall and winter grazing. No-till seeding into grain stubble or sod is recommended. Herbicides must be used to control weeds or suppress sod prior to planting (see “No-Till Forage Seeding,” above). Plant seed in 6- to 12-inch rows, and place no deeper than ½ inch. Apply nitrogen at seeding time.
For suggested seeding rates, see “Forage Selection and Seeding Rates,” above.
Rape. Rotationally graze, strip graze, or greenchop 90 to 120 days after establishment. Leave 6-inch stubble for quick regrowth.
Turnips. Rotationally graze or strip graze 70 to 90 days after establishment.
Swede and kale. Rotationally graze or strip graze 150 days after seeding.
Brassica crops are very high in crude protein and energy but extremely low in fiber. Because of their low fiber content, brassicas should make up no more than two-thirds of the daily livestock diet. Brassicas should be supplemented with grass pasture or hay.