Ohio State University Extension
Department of Horticulture and Crop Science
2021 Coffey Road, Columbus, Ohio 43210-1044

Emergency and Supplemental Crops for Forage

AGF-019-90

Periodically there is a need for emergency or supplemental crops for use as forage. It may be because of frost heaving and severe winter injury of alfalfa, unsuccessful new seedings, adverse weather conditions, or other reasons. Several options are available to provide grazing, hay, and silage. Factors to consider in deciding which crop to grow are: crop use, seed cost and availability, seeding and harvest dates, and relative yield and quality.

Nitrogen Fertilization Of Grass Meadows And Pastures

Alfalfa-grass meadows may have sufficient stands of grass to produce satisfactory forage yields if fertilized with nitrogen. These should be fertilized as early as possible with 60-90 pounds of nitrogen per acre, such as 150 lb per acre of urea. Spread a 1-1-1 or 2-1-1 ratio fertilizer where there is a need for phosphorus and potassium. The nitrogen effect lasts for a 6 to 8 week period so additional nitrogen may be needed to stimulate growth again later in the season, provided moisture is adequate. Similarly, fertilization of pastures to enhance forage production is another option.

Small Grains

Small grains such as oats, wheat, barley, triticale, and rye have all been used as hay, silage, and pasture. Early removal as hay or silage provides good quality feed and allows double cropping with a warm season annual such as sudangrass or a sorghum-sudangrass hybrid for additional feed. Good quality, high protein feed, and maximum production per acre are obtained by harvesting as silage. Nitrogen fertilizer applied at 50-75 lb per acre will optimize yield. Harvesting at boot stage is recommended for high producing dairy cows; dough stage for growing or brood animals. Results from a Minnesota study show the effect of maturity dates on crude protein and digestibility (Table 1 and 2). Wilting before chopping for silage is necessary because of the high moisture content.

TABLE 1. Percent crude protein of four small grains harvested at several stages of maturity - Minnesota experiments, 1982.
	------------Maturity Stage-----------
Spring-seeded	Boot	Milk	Dough	Average
	-----------(% crude protein)---------
Wheat	22.8	15.7	11.9	16.8
Triticale	22.0	15.2	11.6	16.3
Oats	20.5	14.6	11.5	15.5
Barley	23.4	15.7	12.3	17.1
Average	22.2	15.3	11.8

TABLE 2. Dry matter digestibility of four small grains harvested at several stages of maturity - Minnesota experiments, 1982.
	------------Maturity Stage-----------
Spring-seeded	Boot	Milk	Dough	Average
	-----(% dry matter digestibility-----
Wheat	76.2	63.3	58.8	66.1
Triticale	79.6	66.4	61.3	69.1
Oats	77.6	61.5	56.8	65.3
Barley	81.3	68.5	64.4	71.4
Average	78.7	64.9	60.4

Barley had higher crude protein and digestible dry matter concentrations than did oats at all stages of maturity (Tables 1 & 2). Barley forage was more digestible than was oats largely due to a higher proportion of highly digestible inflorescence in the total dry matter of barley at all stages. Spring wheat also contained more crude protein than did oats. Wheat and oats had similar digestibility. Triticale had intermediate crude protein concentration and intermediate digestibility. Barley also had lower concentrations of neutral detergent fiber (cell walls) and acid detergent fiber than did the other species. Rye as forage is used primarily for grazing.

In an Ohio study (Ohio Forage Report, 1988, p. 24-27, 31) Ogle oats seeded April 18 at 2-1/2 bushels per acre and harvested on June 18 at late boot stage produced 2.79 tons dry matter per acre. The quality of the oat forage compared with alfalfa is shown below.

TABLE 3. Chemical composition of oats and alfalfa grown at Wooster, Ohio, 1985.
	Oats	Alfalfa
Harvest date	June 18	May 23
Stage of growth	late boot	mid-bud
Dry matter, %	13.1	19.4
Crude protein, %	13.3	21.8
Acid detergent fiber (ADF)	42.2	33.7
Neutral detergent fiber (NDF)	65.0	39.5

Fall seeded small grains are used for forage as early spring pasture, hay or silage. Yields and the chemical composition of several fall-seeded small grains grown at Wooster are shown in Table 4. Wheat outyielded rye and spelt and feed quality was good. Seeding 12 days earlier (Sept. 13 vs. Sept. 25) resulted in a substantially higher yield the following spring.

TABLE 4. Yield and chemical composition of fall-seeded small grains harvested April 28, 1977, Wooster.
Crop and seeding date	Yield T/A, DM	% DM	% CP	% ADF
Arthur wheat
Sept. 13	2.19	13.2	18.1	27.6
Sept. 25	1.31	12.0	21.1	26.3
Rye
Sept. 13	.92	13.5	15.6	31.6
Sept. 25	.32	14.3	18.8	29.6
Spelt
Sept. 13	1.15	15.9	19.5	29.8
Sept. 25	.56	15.1	----	----

Oats And Field Peas

Field peas and spring oats were commonly grown together in earlier years for hay and silage in the northern states and Canada. Northern Ohio is in the area of adaptation of field peas as a spring crop. Field peas are similar to garden peas in appearance and growth. The combination of oats and field peas harvested early provides a high quality, high protein feed. This could be double- cropped with a warm season annual. Field peas should be inoculated and drilled in early spring at 60-90 lb per acre. Seed availability and cost limit the usefulness of this combination. Field peas when grown alone are harvested when the pods are formed; with oats, harvest according to the maturity of the oats. Field peas provide a high quality, good protein feed for use as silage or hay. Morrison's Feeds and Feeding lists field pea hay at 14.9 percent crude protein; field pea-oat hay at 12.2 Earlier harvest would increase the percent crude protein and nutritional quality.

Sudangrass And Sorghum-Sudangrass Hybrids

Sorghum-sudangrass hybrids and sudangrass are the most widely used supplemental or emergency forage crops in Ohio. Seeded from May 20 to June 10, about 10 to 14 days after corn planting, they grow rapidly and can be used as pasture, hay, green-chop or silage. Drill them into a good seedbed at 25 lb/acre rate for sudangrass, and 35 lb/acre for sorghum-sudangrass hybrids. Fertility requirements are similar to corn.

These annual grasses are usually ready for grazing 5 to 6 weeks after planting. Allow the plants to reach 18 to 24 inches height before grazing. Subdivide the field for grazing or graze alternately with other pastures. The pastures should be heavily stocked so that the growth is grazed down rapidly. Excellent stands may be expected to carry 2 or 3 head of mature livestock per acre during the peak period of growth in mid-summer. These crops can also be used for green-chop and provide large quantities of green feed by early summer.

For hay, harvest when about 30 inches in height. Because of coarse stems, a hay conditioner should be used to hasten drying. Sorghum- sudan and sudangrass are slower to dry than the commonly used hay crops because the leaves and stems are coarse and high in moisture. Harvest sudangrass and sorghum-sudangrass hybrids for silage in the soft dough stage. At this stage moisture content is satisfactory for making silage and wilting is not necessary. All of these crops contain a substance which converts to prussic acid and under certain conditions can be harmful to livestock. For this reason do not graze or feed plants until they reach 18 to 20 inches in height. Drought, cold weather, or frost extends this unsafe period. Do not feed ensiled material for 2 to 3 weeks after filling. Green-chop should be cleaned up in a relatively short time and not allowed to stand overnight on loaded wagons. Remove livestock from material that has been frosted.

Tables 5 and 6 compare the yield and quality of sudangrass, sorghum- sudangrass hybrids and pearl millet. Harvesting more frequently reduces total yield (Table 5), but the forage is of higher quality.

A comparison of a sorghum-sudangrass hybrid (Trudan II) with a pearl millet (Millex 22) is shown in Table 6. Pearl millet is a warm season annual grass, largely grown in the south. It is a different species than the foxtail millets grown for seed and occasionally for forage. It has a long cattail-like seedhead. It does not have the prussic acid potential of the sorghums. It MUST BE CUT AT 6 TO 10 INCH STUBBLE HEIGHT to ensure regrowth after a harvest. Pearl millet was similar to the sorghum-sudangrass hybrid in yield and quality in the Wooster study (Table 6).

TABLE 5. Dry matter yields of sudangrass and sorghum-sudangrass hybrids, Wooster and Columbus, Ohio.
		Wooster	Columbus	Wooster	Columbus
Cuts	Usage	-------1966-------		--------1965------
2	silage	4.16	5.38	3.82	6.30
3	hay	3.02	3.76	3.23	5.48
4	pasture	2.82	4.10	2.55	3.68

TABLE 6. Dry yield and chemical composition of a sorghum- sudangrass hybrid* and a pearl millet** seeded May 22 and harvested at 30 inches and at 6-inch stubble height.
	--Trudan II*--		--Millex 22**--
	Yield	%	Yield	%
Harvest date	lb/A, DM	CP	lb/A, DM	CP
July 10	1,990	11.0	1,951	10.1
July 30	1,602	12.9	1,372	14.2
Aug. 20	1,511	10.4	2,430	9.4
Sept. 10	1,668	--	--	--
Oct. 17	174	--	2,448	--
Total, lb/A	6,942	--	8,201	--
Total, T/A	3.47	--	4.10	--
Avg. % TDN	67.4	--	62.8	--

Soybeans

The earliest use of soybeans in the U.S. was for hay and silage. Later, soybeans switched almost entirely to an oilseed crop, and alfalfa and other superior forages replaced it as a forage. Early studies in Ohio and elsewhere showed soybeans to be an acceptable and palatable silage if wilted to reduce moisture content. Soybean hay varied widely in feeding value, depending on its leafiness, coarseness of stem, and how well it was cured. The coarse stems of the hay resulted in some refusal by animals, with refusal up to 10 to 15 percent of the hay fed.

Soybeans were grown for silage during 1983 and 1984 at Wooster. In 1983 the variety "Amcor" was seeded June 9 and harvested August 9; in 1984 Amcor and Pella were used, seeded June 8 and harvested August 17. At harvest the plants had formed pods, but the lower leaves were still green. Similar yields were obtained both years: 2.1 tons per acre dry matter. The chemical composition of Pella soybeans at harvest in 1984 is shown in Table 7. Animal acceptability of the silage was very good. The soybeans used in these studies were soybeans grown for grain. Forage-type soybeans will yield somewhat more total forage.

TABLE 7. Chemical composition of three legumes grown for silage at Wooster, Ohio, 1984.
Forage	Variety	Harvest date	Growth stage	DM %	CP %	ADF %	NDF %
Alfalfa	Vernal	5/25	early bud	14.6	22.4	31.1	35.2
Red clover	Arlington	6/6	early bud	10.6	18.9	32.1	35.7
Soybeans	Pella	8/14	early pod	15.9	16.2	40.6	48.6
CP: Crude protein ADF: Acid detergent fiber-a measure of dry matter digestibility; the lower the ADF value the higher the digestibility. NDF: Neutral detergent fiber-a measure of indigestible fractions that affect rate of intake by animals; the lower the value the greater the rate of forage intake.

Miscellaneous Crops

Brassicas (turnips, rape, kale, etc.) are fast growing crops that can provide high quality forage which is particularly suitable for animal grazing. They are usually seeded (1) in May for summer grazing, or (2) during July-August for late fall-early winter grazing. May-seeded rape and kale can be green chopped for feeding to confined animals. All brassicas are very high in crude protein and energy, but extremely low in fiber. Their low fiber content means that animals should receive supplemental grass hay or pasture with brassicas comprising no more than two-thirds of livestock diets. See Agronomy Facts AGR-020, Brassicas for Forage, for more specific production and utilization information.

HAIRY VETCH is a winter annual that has been used in Ohio as a green manure crop, seeded in the summer or fall. Research in Delaware, growing it in combination with winter wheat, winter barley or rye has shown good yields of high quality silage. Seed vetch at 15 to 20 pounds per acre drilled in a prepared seedbed or broadcast into stubble corn. Summer vetches are used in southern states drilled with oats as an annual forage crop. Hairy vetch contains many hard seeds and can become a weed, especially in wheat. Hard seeds continue to volunteer for many years. For more information on hairy vetch see Agronomy Facts #AGF-006, Hairy Vetch as an Ohio Cover Crop.

Prepared by:
Dr. R. W. Van Keuren
Agronomist Emeritus, OARDC

John F. Underwood
District Agronomy Specialist