The Production of Grass Seeds

THE GROWERS of seed aim to grow good seed of species and varieties that are in demand and to achieve economical production.

They know that it is easier to grow clean seed than to clean it up after harvest, and that once the seed reaches maturity they can do little more to improve its innate quality.

The best seedgrowers are specialists. Seed production is their main farm enterprise. They have made many technological advances in the art of growing seeds.

Research workers, in studies of effects of environment and cultural practices on the life history of the grass plant, are changing this art into a science.

Some sections have become outstanding in the production of seeds because of conditions that favor low cost of production or a superior quality of seed or both.

Among the conditions are choice of crops; suitable soils; favorable growing seasons; ample supply of water; absence of objectionable weeds; warm, dry seasons for curing and harvesting seed; and the use of correct cultural and management practices.

Some seed is harvested from native grasslands, primarily in the Great Plains. The practice developed from the demand for seeds of the native grasses for converting croplands to grass and improving rangelands. Such seed harvests are sporadic. They occur only when seasonable moisture conditions are unusually favorable, but it is not uncommon to obtain several million pounds of seed annually in this way. No attempt is made to encourage development of seed by cultural or management practices.

Another source is the pastures of tame grass of the subhumid and humid areas of the Midwest, South, and East. They sometimes are fertilized and managed for seed production, but their primary use usually is for pasture or hay. A seed crop is taken when the seed appears to be more valuable than the forage.

A third source, the most dependable and the one we discuss in this chapter, is the grass crops grown primarily for seed.

TWO BROAD GROUPS of grasses are based on their season of growth.

Cool-season grasses grow actively at cool temperatures, develop rapidly in the spring, are more or less dormant during periods of high temperature and drought in summer, and recover active growth in the fall.

Most of the perennials among them have good winter hardiness. They flourish in the northern half of the United States.

They include the fescues, wheat-grasses, bluegrasses, bromegrasses, orchardgrass, timothy, ryegrasses, bent-grasses, and redtop.

The seedgrowers of the Pacific Northwest and Intermountain regions give special attention to perennial and common ryegrass; red, chewings, and tall fescues; bentgrass; Kentucky blue- grass; orchardgrass; and several wheat-grasses.

The wheatgrasses, smooth brome, and Russian wildrye are grown in the northern Great Plains.

Warm-season grasses make their maximum growth during the summer.

They start spring growth about 3 weeks after cool-season grasses and cease growth with the first hard frost in the fall. They are predominant in the southern sections, where the long growing seasons have high temperatures and precipitation in summer. Much seed is produced in the High Plains of western and southern Texas, and in western Oklahoma, Kansas, and Nebraska.

Some of the grasses in commercial production are buffelgrass, blue panicum, King Ranch bluestem, Caucasian bluestem, big sand bur, Arizona cottontop, plains bristlegrass, green sprangletop, sideoats grama, blue grama, little bluestem, sand bluestem, big bluestem, switchgrass, indiangrass, sand lovegrass, and bermudagrass.

THE ADAPTATION of a crop to its environment is reflected in its development and its yield of seed.

Warm-season grasses, for example, are not grown successfully in the Pacific Northwest, where the climate favors the cool-season grasses. Species and variety adaptation often is less limiting to the grower of grass seed than to the forage producer, however, because his crop is grass seed, which may be used elsewhere.

When seed is produced under special culture and management, environment often is less restrictive. Seed therefore may be produced in one area for use in another.

Quality is a watchword of the farmer who specializes in growing grass seed.

The factors that mean quality in the seed he plants and the product he sells usually rank so: Genetic or varietal purity (Is it true to type?); mechanical purity (Is it free from inseparable seeds of other crops and weeds that cannot be economically controlled in the field and from undue quantities of inert matter?); germination (Will the seed produce vigorous healthy seedlings?).

To attain those standards, the grower must plant seed stock of high quality. He must select land that is sufficiently isolated to minimize cross-pollination from other fields and is free from weeds and other crops that are highly competitive or have seeds that are inseparable from the sown crop.

Grasses vary in adaptability to different soil conditions, but all respond in seed yields to the soil factors that favor the complete development of plants.

The most important conditions are adequate depth of soil to permit abundant development of roots; favorable drainage and supply of moisture; aeration, nutrient-supplying ability, and tilth of soil; and topography.

THE SEEDBED should have the proper moisture, temperature, tilth, and fertility to stimulate germination, rapid emergence of seedlings, and quick establishment of the stand.

Methods of preparing the seedbed for sowing grass seeds vary with soil type, climate, time of sowing, kind of grass, and the grower.

A plowed, well-tilled, and firm seedbed usually is prepared just before the planting.

If fertilizer or soil amendments are used, they may be mixed into the soil or applied in bands with the seeding.

Seed fields often are established in the Great Plains in the standing stubble of the previous crop. The stubble helps to control blowing soil, catches snow, reduces evaporation, and provides a firm surface.

MAXIMUM SEED production of most grasses can best be attained with wide-spaced rows—24 inches or more apart. Exceptions are stoloniferous species, such as buffalograss and bermudagrass, and low-growing bunchgrasses, such as blue grama and perennial ryegrass.

Wide-spaced rows result in cleaner seed, higher yields, better control of weeds, more economical use of fertilizer, and longer productive life of stands. They also permit a lower seeding rate and the stretching of limited or high-priced stock seeds of new varieties.

Row culture affords better utilization of limited moisture. Under irrigation, row planting facilitates furrowing and gravity irrigation.

Most row spacings are 24 to 48 inches apart, depending on the seeding, cultural, and harvesting equipment available; type of grass; and the grower’s preference.

Row spacings up to 84 inches have been used successfully for Russian wildrye in the northern Great Plains.

Perennial grasses usually yield more seed when sown at rates lower than the optimum for forage production. The most effective seeding rates vary, naturally, with size of the seed. The amount for cultivated rows is one-half pound to 4 pounds an acre, and 2 to 16 pounds for close drills (6 or 7 inches).

Rhizomatous, sod-forming perennial grasses, such as smooth brome and intermediate wheatgrass, present special problems in the control of the plant population because they are vigorous spreaders. This habit results in dense growth, which is known as sod binding, and a rapid decline in yields of seeds.

Sod binding often can be delayed and seed production of some sod-bound grass often can be restored by providing adequate nitrogen, postharvest burning, and reducing the plant population by mechanical renovation.

Annual grasses, such as common rye-grass and sudangrass, usually respond in yields to heavier sowing rates, or about the same as for forage production. When the soil moisture is limited, the seed fields of sudangrass often are sown at lower rates in rows.

A DRILL should be used for planting. It has several advantages. The rate of sowing can be controlled more accurately. The seed is distributed more evenly. Seed can be covered at a uniform depth. Seedings can be made in wide-spaced rows. Fertilizer attachments can be used to place the fertilizer in bands beside or below the seed.

The fluted feed grain drill, modified to sow at the desired intervals, is popular. Drills for beets or beans, corn planters, and shop-built seeders frequently are used for sowing rows and are superior to a grain drill.

Many seedgrowers in the southern Great Plains use a specially built, two-row, tractor-mounted planter.

It is equipped with cotton boxes (for light, trashy, or awned seed) and vegetable boxes (for small, free-flowing seed). It has double-disk furrow openers, with depth-control bands, and heavy press wheels. All are important features of a planter unit.

Chaffy, fluffy, or heavily awned seeds are sometimes mixed with free-flowing material of a similar weight, such as rice hulls, to aid in getting the seed through a drill.

SOWING too deep causes many failures to get stands of grass. Seeding equipment therefore should have accurate devices to control depth.

Desirable sowing depths vary with the type of soil, kind of seed, depth to moisture, and the season of seeding.

For quick emergence of seedlings, the seed must be placed in moist soil—but that does not mean seeding so deep that the seedlings cannot emerge.

In general, bentgrass and Kentucky bluegrass should be seeded no deeper than one-fourth inch; the fine fescues, timothy, and most warm-season grasses, no deeper than one-half inch; and smooth brome, wheatgrasses, ryegrass, tall fescue, meadow fescue, orchard-grass, and tall oatgrass, no deeper than 1 inch.

Greater depths are permissible on light soils. Shallower sowings are advisable on heavy soils.

Fertilizer, especially nitrogen applied at seeding time, often helps in the establishment of grass seedlings.

Broadcasting is not a good way to apply fertilizer to newly seeded rows. When the fertilizer is banded about 1 inch below the seed or below and slightly to one side of the drill row, the seedlings make better use of the fertilizer, less goes to the weeds, and the establishment of the grass is hastened and improved.

Companion crops are not recommended generally. Stands almost always are better when grass is sown without them. The rapid growth of companion crops places the slower developing grass seedlings at a serious competitive disadvantage for light, nutrients, and the moisture, especially when the field is not irrigated.

Seeding with a nurse crop at half the normal rate may be justified when protection from erosion by water or wind is needed.

The best date of planting may depend somewhat on the rainfall and temperature pattern.

Warm-season grasses are commonly planted in the spring 2 to 4 weeks before the time one expects seed-germinating temperatures. They can be planted successfully in midsummer with frequent irrigation.

Warm-season grasses are planted in spring or early fall in the far South.

Cool-season grasses usually are planted in early spring or early fall in the Great Plains and the Intermountain region. Late-fall plantings are made occasionally.

In the Northwest on unirrigated lands, spring seeding—as soon as a firm, fine, weed-free seedbed can be prepared—is generally best.

If weeds are numerous, a few weeks of fallow will destroy several crops of weed seedlings.

Late spring sowing of the small-seeded grasses, such as bluegrass, is risky without irrigation. There is less risk with smooth brome and other large-seeded species. A well-managed spring seeding usually requires a minimum of weed control and produces a seed crop the following year.

On irrigated lands, late spring or summer seedings made before September 1 on weed-free land require little effort for weed control and usually make a seed crop the next year.

Fall seeding of grasses presents problems in weed control in places where winter annuals grow in abundance. A seed crop the following year seldom is produced from fall seedings. One notable exception is annual or common ryegrass, which normally is sown in the fall and produces its seed crop the next year.

Fall is a good time for seeding cool-season grasses in the Great Plains, where winter annuals are not a serious problem.

Managing the stand of seedlings is of utmost importance in the rapid establishment of seed fields.

If water is available, irrigations should be frequent enough to keep the soil moist and light enough to prevent erosion or silting. With sprinkler irrigation, the problems attending the furrow method are reduced. After the grass seedlings are well established, irrigations may be of lower frequency and longer duration.

If the new grass plant is to develop rapidly, weeds should be controlled during the first year. Wide-row seedings can be weeded by cultivation and spraying. Some handwork may be needed.

The early cultivations should be done with great care to avoid covering or uprooting young grass seedlings. Injury to the roots of the young plants can be lessened by cultivating no deeper and no oftener than is necessary to kill the weeds.

When seedlings have four or five leaves, 2,4-D may be used to control broad-leaved weeds.

Removing the leaves of young grass retards its development. Clipping to prevent seed formation and reduce the topgrowth of weeds therefore is not a good substitute for cultivation or hand weeding but is better than no control at all.

Pasturing of seedling grass in lieu of clipping should be carefully controlled. Livestock will destroy seedlings by pulling out and trampling them.

Insects and diseases seldom are serious problems on new seedings of grass, although slugs, cutworms, and wire-worms are sometimes destructive in the West. Grasshoppers may require control measures, especially in the Great Plains.

Damping-off organisms of seedlings may cause losses in stands—usually minor but occasionally severe in some sections.

THE MANAGEMENT of established grass for highest yields of seed requires that the grower fit his production practices to the needs of the grass plant during the different phases of its growth.

Grasses go through a regular seasonal cycle, in which temperature and daylength are vital influences in their development.

All grasses do not follow the same seasonal pattern. At a given geographical location, however, this rhythmic process is repeated each year with minor deviations due to variations in the environment.

The seed crop of most perennial cool-season grasses begins the fall prior to harvest. Sometime before the emergence of the seed heads in the spring, the head is initiated as an almost microscopic group of rudimentary flowers from vegetative tissue in the basal part of the shoot or tiller. The length of time between initiation and emergence varies with the kind of grass. After the seed crop has matured, the tiller that bears seed next year will arise and gain enough vigor during the rest of the growing season to become ready to form floral parts.

The tiller usually produces a seed head the following year if it has a minimum specified number of leaves for the species by a certain date.

Yields of seed the following year usually are lower when new tillers are restricted in number or reduced in vigor by fall drought, lack of fertility, and excessive defoliation by insects, disease, pasturing, clipping or late burning.

Conversely, the presence of many tillers in condition to form floral parts, followed by vigorous growth, favors high yields of seed.

The time of initiation of the floral shoot in our important cool-season perennial grasses is known definitely in only a few geographical areas. Length of day largely determines when initiation of flowers takes place.

More research is needed to give a clear picture of the development cycles of grasses as they occur under different environments. The work already done, however, is of great value in understanding the responses of the species studied to various environmental factors and has resulted in improved management practices.

FERTILIZATION with nitrogen is one of the seedgrower’s most effective means of stimulating abundant and vigorous growth of fertile tillers and increasing yields.

The amount and time of application is determined by the fertility level of the soil, the kind of grass, the manner in which plant residues are handled, and the amount of available water.

All grasses may not respond alike to time of fertilizer application.

Such grasses as Kentucky bluegrass and tall fescue, which go through floral initiation in the winter, respond to split applications of nitrogen in the fall and early spring and give better yields of seed.

Grasses that reach floral initiation in the spring make less efficient use of nitrogen applied in the fall than nitrogen that is applied in the spring.

Warm-season grasses respond best to nitrogen when it is applied soon after growth begins in the spring and (in the case of grasses that produce more than one seed crop) immediately after the harvest of each crop.

An annual application of 30 to 40 pounds of nitrogen to the acre usually is enough in areas of limited rainfall where there is no irrigation.

In more favorable areas and under irrigation, 60 to 200 pounds of nitrogen are applied annually. The higher rates usually are applied in split treatments to old stands or in localities where moisture is plentiful.

Phosphorus and potassium, the other major nutrients, generally do not limit production on western soils, but their use will increase as cropping depletes natural fertility. Phosphorus may be advantageous under some conditions to improve strength of the straw or to make more effective use of nitrogen.

The lack of sulfur and boron limit production on a few western soils.

Irrigation is needed for consistently high yields in most areas.

With lengthening days and rising temperatures of spring, grass should begin to grow vigorously. If lack of soil moisture limits growth, irrigation should be given as needed to carry fertilizer into the soil and sustain strong growth.

Plentiful moisture is needed during pollination and while the seed is filling. Most growers of grass seed apply nitrogen fertilizer heavily in the spring. Losses of nitrogen by leaching often result from overwatering. Uneven use of water results in uneven development and maturity.

When the seed crop nears maturity, irrigation usually is withheld to promote uniform ripening.

Irrigation may be needed in the late summer and fall to stimulate formation of abundant new shoots and build up food reserves in the overwintering plant tissues. Where irrigation of crops of grass seed is not usually needed, abnormal fall drought sometimes limits the formation of new shoots. Irrigating to relieve this condition will bring about the fall development required to produce a high yield of seed in the next crop.

Pastured or harvested aftermath of cool-season grass crops after a seed crop has been removed is a valuable byproduct. The combination of production of both seed and livestock can be efficient and profitable. Yields of seed are not affected adversely by removal of the aftermath following seed harvest.

With warm-season grasses, there is little opportunity for pasturing, because they mature seed in midsummer or late summer near the end of their seasonal growth.

WEEDS must be controlled if the seed crop is to be of high quality.

The use of good seed and special care given to establishment of a full initial stand do much to solve the problem of weeds in the established stand.

Chemical weedkillers, such as 2,4-D, have simplified and reduced the cost of weed control, but they have not eliminated the need for using clean land, cultivating row seedings, and hand roguing to produce seed of high quality.

DISEASES have become increasingly destructive.

Blind seed disease is severe on perennial ryegrass when recommended cultural control methods are not practiced.

Ergot affects most grasses grown for seed.

The grass seed nematode affects chewings fescue and bentgrass.

Dwarf bunt injures the first seed crop of many grasses but spring sowing gives good control.

Leaf rust and stripe rust are especially injurious to Kentucky bluegrass.

Orchardgrass is subject to severe injury by a number of leaf diseases that are most active in the spring.

In Oregon, afterharvest burning is an important part of the recommended control program for blind seed, ergot, nematode, rust, and some other leaf diseases. Large propane burners sometimes are used to supplement the field burn to destroy disease inoculum where there is doubt that the field burn was adequate.

THE GRASSHOPPER was among the first recognized insect pests of grasses.

The sod webworm works on the basal parts of the grass plant and may be destructive to the fine fescues and Kentucky bluegrass.

Silvertop has a possible relationship to thrips and is destructive to seed crops of most perennial grasses.

Other commonly destructive insects are the Banks grass mite, aphids, mealy bugs, cutworms, stem maggots, and meadow plant bugs.

Afterharvest burning is an aid in controlling the sod webworm, silver-top, meadow plant bugs, thrips, mites and others.

Pesticides also are effective against certain insects.

Field mice sometimes are destructive in grass crops. Heavy populations have practically killed out grass fields. Such infestations are destructive to crops in general, and areawide control with poison baits is required.

THE REMOVAL of crop residues after harvest is important in maintaining maximum yields of grass seed. Development of seed stalks and yields of seed are improved if the grass aftermath is removed.

Since harvesting with a combine has become general, considerable quantities of loose straw must be removed from the field. Shredding with a rotary mower or chopper and attempts to incorporate the material into the soil have been unsatisfactory where the residue is heavy.

Many growers windrow the straw and bale it for livestock roughage or bedding and pasture the aftermath.

In some places, postharvest burning to remove crop residues is increasing. This method has some practical merits. It is cheap and has value in the control of some injurious insects and diseases. Injurious insects and diseases usually increase when crop residues are not removed.

Preharvest crop conditioning with desiccants—chemical sprays that kill and cause quick drying of the exposed plant parts—may be used before direct combining of the standing crop.

The method appears to be practical only under conditions of high temperature and low humidity and on open erect grass stands. The most commonly used material is DNBP, a dinitro spray. Application is by airplane at rates of 1 to 3 pints in 10 to 15 gallons of weed oil per acre. The crop should be ready to combine within 3 to 5 clays after treatment.

Chemical injury to grass seeds and reduction in germination may occur from use of a desiccant. Injury to tall fescue and Kentucky bluegrass seeds has been observed. Seeds of sudangrass and blue panicgrass are tolerant because of their heavy, waxy hulls.

When to harvest is a problem that confronts all seedgrowers. In every grass seed field, as maturity approaches, there are grass plants in different stages of seed ripening. On every grass plant also are seeds in various stages of maturity, especially in humid weather and when fields are irrigated.

The mature seed shatters in many grasses so that it may be lost on the ground if it is left too long. It is not practical therefore to leave the crop unharvested until all of the seeds are ripe.

The grower’s question of when to harvest is decided by estimating when he can get the most mature seed without excessive loss by shattering of the earliest seed.

Grass seeds may reach physiological maturity or attain maximum dry weight before the head appears ready to harvest. Higher yields may be possible because of reduced shattering loss with earlier harvesting than is generally practiced. In general, grass seed is likely to be physiologically mature when it has passed the milk stage and is in soft-to-medium dough.

Direct combining of the standing seed crop and bulk handling of the seed do not mean earlier harvesting when facilities for quickly reducing the moisture in seed, which may average 35 to 45 percent, are limited.

Newly harvested seed of high moisture content will heat and mold, and losses in germination and good appearance will occur if it is left in the bulk for just a few hours.

Early harvesting is generally practiced only when the crop is windrowed and allowed to cure in the field before combining.

Indeterminant seed maturity is a problem with a number of warm-season grasses. Harvest generally is delayed until there is some shattering from the tips of the inflorescence. Then harvest must be completed in a few days. At that stage, most of the seed has reached a maturity that will give good germination.

We do not know exactly when the growing of grass seed became a distinct enterprise in the United States. Orchardgrass, timothy, and Kentucky bluegrass probably were the first grasses to be harvested for seed.

The first known commercial production of seed of orchardgrass occurred possibly before 1850 in Kentucky. Timothy seed was a sizable crop item in Illinois in 1877. Stripping seed from bluegrass pastures in Kentucky was a well-established practice in 1900. Smooth bromegrass seed was harvested in Kansas about 1895. It is not known if any of these early plantings were made primarily for seed production rather than for forage with only intermittent seed harvests at opportune times.

We do know that much of our domestic production of grass seeds came as byproducts in the early part of this century. The actual planting of grass fields for the primary purpose of growing seed crops seems to have begun on sizable scale between 1910 and 1920. Expansion was gradual until the 1930’s, when the effects of drought and the need for soil-conserving practices brought increased demand for grass seeds and stimulated seed production.

The names and doings of pioneers in important undertakings always are of special interest. We list a few men who we know pioneered in growing grass seed.

The first commercial harvest of orchardgrass seed, possibly before 1850, was said to have been at Goshen, Ky.

Edwin C. Johnson of Portland, Oreg., grew seed of common ryegrass before 1900. Smooth bromegrass seed was first harvested about 1895 by the Achenbach brothers of Washington, Kans., and Charlie Jeanerette of Madison, Kans.

Dr. E. B. White of Leesburg, Va., and Robert N. Legard of Hillsboro, Va., began producing seed of orchard-grass shortly after 1900. They found it to be a good cash crop that required little labor, and growing the seed soon became popular in northern Virginia.

Among the first growers of perennial ryegrass seed, about 1920, was J. E. Jenks of Tangent, Oreg. Max Heinrichs, a German immigrant, specialized in growing seed of smooth bromegrass, tall fescue, and crested wheatgrass near Pullman, Wash., before 1930.

APPARENTLY the first commercial grass seeding in cultivated rows was made in 1927 with crested wheatgrass by Leroy Moomaw of Dickinson, N. Dak. Neal and Sam Parker of Creston, Mont., also made commercial plantings in rows in 1932, as did Walter Holt of Pendleton, Oreg.

Howard Wagner of Imbler, Oreg., followed with row culture within a short time, but special recognition is due him for the high standards of seed quality he maintained in his crops of crested wheatgrass, fescues, bentgrass, bluegrass, and native grasses.

Commercial culture in rows of native grasses of the Great Plains was begun with switchgrass and sideoats grama about 1942 by Clyde Dennis, Lamed, Kans.

Among others who followed him were H. W. Clutter of Garden City, Kans., and Harold Hummell of Fairbury, Nebr. Pioneers in the commercial harvest of bluegrama, buffalograss, and bluestem seed from native grass lands were Tom Munger, Enid, Okla.; Bob Hartley, Vinita, Okla.; and Glen Miller, Lincoln, Nebr.

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