The role and prospects of growing perennial legumes in forage production

Why legumes are more profitable than grasses and how to sow them

The area under perennial grasses accounts for 845–940 thousand hectares, of which 600 thousand hectares are occupied by legume crops (including 240 thousand hectares under clover). The total size of these lands is close to optimal, but the crop structure requires adjustment due to the predominance of grasses. Without sufficient application of nitrogen fertilizer, the productivity of grasses is no more than 30% of the productivity of legumes. To solve the problem of protein deficiency in dairy farming and cattle fattening, the share of sown legume grasses must be increased to 60%, leaving grasses primarily for seed production (up to 8%).

• Target proportion of legumes — 60%
• Protein yield of alfalfa or goat's rue — 2.5–3.0 t/ha
• Seed sowing rate — 4–5 million units/ha
• Sowing depth — 1–3 cm

The main advantage of legume grasses is their ability to fix atmospheric nitrogen, which eliminates the costs of expensive nitrogen fertilizers. Crops of alfalfa or eastern goat's rue produce up to 2.5–3.0 tons of protein per hectare during the growing season, which is 2–3 times more than the indicators of grass crops. The resulting protein is balanced in amino acid composition and is easily absorbed by animals, increasing the overall digestibility of the ration. In addition, the sod of perennial legumes serves as an excellent predecessor, protects the soil from water and wind erosion in spring and autumn, and also prevents nutrient leaching.

In practical forage production, legume grasses are often sown in mixtures with grass components. The success of cultivation depends on the thoroughness of pre-sowing operations and compliance with mowing deadlines. To obtain high-quality feed, it is necessary to adhere to the standard technological scheme.

1. Thoroughly level and compact the soil before sowing.
2. Sow the seeds using a wide-row or conventional row method to a depth of 1–3 cm.
3. Carry out harvesting of the green mass during the "budding — early flowering" phase.

Clover: nutritional value, nitrogen fixation, and crop characteristics

Several key types of legume grasses are cultivated in field forage production. Clover, alfalfa, sainfoin, birdsfoot trefoil, and sweet clover are used for preparing green fodder, silage, and high-protein hay. Each of these species has its own biological characteristics and requirements for growing conditions.

• clover;
• alfalfa;
• sainfoin;
• birdsfoot trefoil;
• sweet clover.

Clover is one of the most common crops of this family. Sowing clover in fallow allows for obtaining high-quality hay and forming a weed-free predecessor for winter cereals. Using this technology, 35–40 centners of valuable protein feed can be obtained per hectare.

The powerful root system of clover penetrates deeply into the subsoil layers of sod-podzolic soils. It loosens the subsoil, enriches it with organic matter, and thereby increases the depth of the arable layer. This property makes the crop an indispensable soil ameliorant in crop rotation.

The clover genus includes about 300 species, of which 25% are polyploids and the rest are diploids. Three species are mainly cultivated in crop rotations: red clover (meadow), hybrid clover (alsike), and white clover (creeping). Meadow clover forms a hollow rounded stem 50–70 cm high, which is prone to lodging under excessive humidity. The bush branches well, forming more than 20 stems from a single tillering node. The root system depends on the earliness of the cultivar: early-maturing forms form a taproot, while late-maturing ones form a tap-fibrous root.

The leaves are trifoliate, the lower ones are long-petioled, and the upper ones are shorter. The shape of the leaf blade is ovate, elongated-ovate, or elliptical. It has a characteristic white triangular spot.

The flowers, numbering about 100, are collected in a head-type inflorescence. The flower has a calyx with ten green veins and a purple-colored corolla, tubular, butterfly-type.

The fruit is a one-seeded, rarely two-seeded, pod.

The seeds are ovate, with a protruding germinal root, flattened, yellowish, brown, or purple in color. The mass of 1000 seeds is 1.6—1.8 g.

Meadow clover is not demanding regarding soil and heat; it is moisture-loving. This is a long-day plant and a light-loving crop. legume grasses 325

Fig. 46. Clover: morphological characteristics of red (meadow) clover (a), hybrid (alsike) clover (b), white (creeping) clover (c); flowering of red clover (d)

The best soils for red clover are loamy. It grows poorly on sandy and sandy loam soils, as well as on acidic soils.

Alsike clover (Trifolium hybridum L.) is a perennial plant up to 80—100 cm tall; branching begins in the first year of life. The root system is better developed than that of red clover and penetrates deeper into the soil. The inflorescence is a pale pink head. The fruit is a 1-2-seeded legume. The seeds are greenish and significantly smaller than those of red clover.

Alsike clover is moisture-loving; in spring, it can even withstand prolonged flooding (up to two weeks). It is frost-resistant but does not tolerate drought. It grows well on heavy, clay, moist, and acidic soils, and drained peat-bog lands.

White clover (Trifolium repens L.) has a creeping stem that ascends only in the upper part. It branches heavily, forming a wide bush. The root is tap-rooted and highly branching; roots also form at the nodes of the stems.

Fig. 47. Inflorescences (heads) of clover: red (a), pink (c), white (d); red clover leaf (b) legume grasses 327. The inflorescence is a white or pale pink head. The fruit is a legume with 2—4 seeds. The seeds are small, rounded, and brownish-yellow.

For grass cultivation in Belarus, new cultivars of red clover are recommended — Yantarny, Ustoylivy, Pratsaunik — and white clover — Volat (late-maturing), Dukhmyany (mid-late), Charadzey (early-maturing).

Alfalfa is one of the best forage crops from the Legume family (Fig. 48, a, b, c). In many countries, it is called the queen of forage crops. It is cultivated for green fodder, hay, and for the preparation of hay meal. One centner of green mass of alfalfa yields 17.2, and hay

Fig. 48. Alfalfa: alfalfa (blue) (a); sickle medick (yellow) (b); black medick (annual) (c) meal — 47.7 feed units. On average, alfalfa hay contains 12—13 % protein, 2—2.5 % fat, 33.3 % nitrogen-free extractives, 25 % fiber, 8 % ash substances, and all vitamins (A, B, C, D, E, K), as well as phosphorus and calcium, which ensure the development of livestock animals, especially young stock. It is a good pasture for pigs.

Alfalfa numbers about 60 species. In Belarus, the following ones are common: alfalfa (blue); sickle medick (yellow); blue alfalfa; black medick (annual, yellow).

Alfalfa (Medicago sativa L.) is a perennial plant. Stems grow from the root collar, branch heavily, and reach a height of 70 to 150 cm. The root system is tap-rooted and powerful, with a thickened root collar that, as it grows, pulls into the soil, thus protecting the plants from freezing. The leaf is compound with two stipules and consists of three leaflets. The plant is heavily foliated. The inflorescence is a raceme. The flowers are lilac-purple with various shades. The fruit is a multi-seeded spiral legume. The seeds are yellow. The weight of 1000 seeds is ~ 2 g.

Alfalfa is a light-loving long-day crop. It is a heat-loving and cold-resistant, drought-resistant, and salt-tolerant crop. It grows on loams and sandy loams with fertile and permeable subsoil.

For meadow grass cultivation in Belarus, new cultivars of alfalfa are recommended: Buduchynya and Avanta AS.

Sickle medick (Medicago falcata L.) differs from alfalfa by a more powerful root system. The inflorescence is a short raceme in the form of a head of yellow flowers. The fruit is a sickle-shaped multi-seeded legume. The seeds are yellow, smaller than those of blue alfalfa.

Blue alfalfa (Medicago coerulea Zess.) differs from alfalfa (blue) by smaller leaflets, pale blue flowers, legumes, and greater drought resistance. It is capable of growing on saline soils. It is late-maturing and blooms 10—15 days later than the blue one. It is cultivated in arid regions on saline and light chestnut soils.

Black medick (Medicago lupulina L.) is an annual plant with a creeping stem, small yellow flowers gathered in small heads, and a single-seeded black legume. It is widely distributed in the wild. In cultivation, it is often sown on drained peat-bog soils.

Bird's-foot trefoil (Lotus corniculatus L.) is a perennial legume. It has a well-branched root system that reaches a depth of up to 1.5 m. The stems are low (35—70 cm), ascending, and form a dense bush with up to 100—150 shoots. The flowers are bright yellow, gathered in umbellate heads (5—8 flowers each). The legumes are elongated, dehiscent, and multi-seeded. The seeds are small, rounded, and dark brown. The weight of 1000 seeds is 1.1—1.4 g.

All these grasses are grown for hay, haylage, for feeding as green mass, preparation of herbal meal, chopped hay, Fig. 49. Bird's-foot trefoil briquettes.

In pure form, they ensile poorly due to the low content of free sugars; ensiling is possible only when using chemical preservatives.

Mowing times and biological features of legume grasses

A feature of perennial legume grasses is the intensive growth of vegetative mass from the regrowth phase to budding. With the onset of flowering, this process slows down, and nitrogen and crude protein are redistributed to the roots for successful wintering. Therefore, the optimal mowing time for all legume grasses is the beginning of the flowering phase. By this moment, the plant accumulates maximum biomass with high feed quality.

Birdsfoot trefoil is a light-loving, long-day crop resistant to frosts and extreme cold. It successfully grows on various soil types, from light sandy loams to heavy clay loams. To improve meadows in production, a new cultivar of birdsfoot trefoil, IZiS, is used.

Sainfoin is represented by two species: common, or vetch-leaved (cokshead) — Onobrychis viciaefolia Scop. (Hedysarum onobrychis L.), and sand — Onobrychis arenaria D.C. (Hedysarum arenarium Kit.). Common sainfoin develops according to a winter-type pattern, so in the first year, it forms only a leaf rosette and does not flower. In subsequent years, the above-ground part dies off for winter, and only the roots and buds in the tillering zone overwinter. Compound odd-pinnate leaves are complemented by large flowers: bright pink-purple in the common species and pink-white in the sand species. New cultivars of sand sainfoin, Karanevichski and Kaŭpatski, have been developed for cultivation.

Sweet clover is used as a honey plant, green manure, and also for preparing hay, haylage, and green feed. Out of 16 species, the most common are the biennial white sweet clover (Melilotus albus Desr.) and yellow sweet clover (Melilotus officinalis [L.] Pall.). Plants with stems 75–300 cm high begin to branch at a level of 25–30 cm, bearing trifoliate leaves and axillary racemes of white or yellow flowers. Elliptical, reticulate-wrinkled pods with a short beak contain oval yellow or yellowish-green seeds. A new cultivar of white sweet clover, Koptevsky, has been developed for meadow seeding.

• Protein content in grain legumes (start of flowering) — 14–18%
• Protein content in dry matter of sweet clover — 19%
• Weight of 1000 sweet clover seeds — 1.5 g
• Application rate of grass crops in mixtures — 4–6 million/ha

Cultivation of Poaceae grasses in grass mixtures

Perennial Poaceae (grass) crops are cultivated in pure stands or in mixtures with grain legumes. These are cold-resistant long-day plants that are well consumed by livestock in hay and on pasture. Each grass stem lives for one year, so the aftermath of the second harvest is formed by new vegetative shoots. Maximum growth of above-ground mass occurs from stem elongation to the end of panicle emergence. Harvesting the sward for feed is carried out in the heading phase.

According to their tillering habit, perennial grasses are divided into three groups. Rhizomatous grasses (couch grass, smooth brome) position their tillering node at a depth of 3–5 cm in the soil. In loose-bunch species (meadow fescue, orchard grass, timothy grass, crested wheatgrass), this node is located at the very surface. Densely-bunching grasses (tufted hairgrass, matgrass) form a dense tuft of shoots pressed against each other.

Timothy grass (Phleum pratense L.) has a shallow fibrous root system. Its hollow stem reaches a height of up to 1 m, is geniculately curved in the lower part, and has a bulbous thickening at the base. The crop is long-lived and capable of producing high yields of forage mass in one place for 5–7 years or more.

1. Thorough leveling of the field surface before sowing.
2. Rolling of the soil to create a firm seedbed and ensure uniform seeding depth.
3. Sowing using a wide-row or standard row method.

To create highly productive hayfields and pastures, grass components are selected taking into account their biological characteristics and nutritional value. They form the basis of the sward, ensuring a stable harvest of green mass and hay. The correct choice of crops guarantees the longevity of the meadow and high quality of the feed.

Timothy grass is excellently consumed by livestock, regrows quickly, and does not yield to other perennial grasses in productivity. In meadow management, the use of the new cultivar Volna, which is distinguished by different ripening times, is promising. Other grass components, such as orchard grass and meadow fescue, form a powerful sod and provide a high harvest.

• 1000-seed weight of timothy-grass — 0.4–0.5 g
• 1000-seed weight of orchard grass — 1.2 g
• 1000-seed weight of meadow fescue — about 2 g

Annual grain legumes for the forage wedge

Annual legumes allow for the rapid production of protein-balanced feed. These crops are photophilous and are classified as long-day plants. At the same time, they are not demanding of heat and moisture, are resistant to frost, and grow successfully on various types of soil.

The group of cultivated annual legumes includes:

• common vetch and hairy vetch;
• grass pea;
• field pea;
• narrow-leaf lupine;
• serradella.