Alfalfa (or lucerne) is a fodder crop related to perennial leguminous grasses.
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Economic importance
Alfalfa hay is distinguished by high fodder qualities, according to this indicator it ranks first among fodder crops , contains a large amount of protein, phosphorus, calcium, and essential amino acids. 100 kg of alfalfa hay correspond to 50.2 feed units and contain 13.7 kg of digestible protein (All-Russian Research Institute of Fodder).
Alfalfa is used for fodder purposes in green form or for fodder preparation (hay, haylage, grass meal). 100 kg of fresh grass harvested in the flowering phase corresponds to 21.3 feed units and contains 4 kg of digestible protein (All-Russian Research Institute of Fodder).
The chemical composition of alfalfa haylage with a moisture content of 48% in terms of absolutely dry matter includes: 15.9% protein, 23.5% fiber, 3.2% fat, 8.2% ash, 49.2% nitrogen-free extractive substances, 2, 2% calcium, 0.3% phosphorus.
100 kg of grass flour correspond to 85 feed units, contain 10-14 kg of digestible protein and 25-30 g of carotene.
When grown without irrigation, alfalfa is mowed 2-3 times during the summer, when irrigated – 4-5 times. Compared to clover, alfalfa in crops is more durable, able to grow in the steppe zone for 3-4 years, in the forest-steppe zone – 5-6 years. The maximum yield falls on 3-1 year of plant life.
Thanks to a powerful root system, it grows and gives good hay yields in the steppe regions with arid climate, contributes to the enrichment of the soil with nitrogen and organic matter, accumulating 200-300 kg of nitrogen and 8-10 tons of root and stubble residues in terms of dry matter in two years. Three-year-old plants are able to accumulate nitrogen in the soil, corresponding to the application of 60-70 tons of manure.
The alfalfa layer serves as an excellent precursor for spring durum wheat, rice, millet, and especially cotton and other crops. Alfalfa-cotton crop rotations provide high yields of cotton with high fiber quality, healing the soil from a fungal infection – cotton wilt. Alfalfa promotes soil desalinization.
It also grows well in the Non-Chernozem Zone, provided that the soil is limed and groundwater is deeper than 2 m.
Alfalfa is the most important component of grass mixtures of irrigated cultivated pastures in the steppe and dry steppe zones, as well as in Central Asia and Transcaucasia.
It can also be used for grazing, but with early, low and frequent grazing falls out of the herbage. Pure crops of alfalfa are suitable for grazing pigs and birds, for cattle – grass mixtures, since in its pure form it can lead to tympania (bloating) in animals.
In grass mixtures, it is used together with awnless brome , wheatgrass and other cereal herbs. Mixtures overwinter better and thin out less, the yield is more stable, resistant to pests and weeds.
History of the crop
Lucerne is one of the oldest agricultural crops. Presumably, it began to be cultivated at the same time as wheat.
Area of cultivation
Lucerne is widely grown in the south and southeast of Russia, in the steppe, forest-steppe zones, the central regions of the Non-Chernozem zone, Belarus and the Baltic countries.
The largest sown areas are concentrated in the Central Black Earth zone, the North Caucasus and the Volga region.
Yield
The yield of alfalfa hay reaches 12-20 t/ha, usually 4-6 t/ha. Yield is highly dependent on moisture conditions. In dry years, the yield can decrease to 1.5-2 t/ha, under irrigation conditions it can increase to 12 t/ha.
The yield of alfalfa seeds is 150-200 kg/ha, maximum – up to 500-800 kg/ha.
Botanical description
Species
Alfalfa includes more than 100 species, on the territory of Russia and the countries of the former USSR there are 36 annual and perennial species of alfalfa, of which the most widespread is sowing alfalfa, or blue, – Medicago sativa L. Also used in production are yellow alfalfa, or crescent, (Medicago falcata L.) and variable alfalfa, or hybrid (Medicago varia). Northern alfalfa (Medicago borealis Grossh.), blue alfalfa (Medicago coerulea Less.), and hop alfalfa are sometimes mentioned .
Varieties of alfalfa are subdivided into blue-hybrid, variegated-hybrid and yellow-hybrid, and sometimes blue-variegated hybrids are also distinguished (All-Russian Research Institute of Fodder). The blue-hybrid group of varieties is cultivated mainly in the south of the country; it differs in the ratio of purple (85-95%) and light purple, almost white (5-15%) color. The variegated group has 50-65% purple corollas and 35-50% yellow. Yellow hybrid group of varieties 20-55% purple flowers and 45-80% yellow.
In field crop rotations of the steppe and forest-steppe zones, as well as on irrigated lands, it is recommended to use blue, blue-hybrid or variegated-hybrid alfalfa, for greening sloping lands – yellow-hybrid and yellow, in floodplains – petro-hybrid, yellow-hybrid and yellow varieties of alfalfa.
Medicago sativa
Root system
Taproot with well developed lateral roots. In the first year of plant life, the roots penetrate to a depth of 2-3 m, in subsequent years – up to 10 m. Approximately half of the mass of the root system is located in the arable soil layer.
A powerful root system allows alfalfa to accumulate a large amount of root residues in the soil. Under the conditions of irrigated agriculture in Central Asia, alfalfa serves as the main source of organic matter for the formation of humus.
In the upper part of the root there is a root neck, or a crown, which is laid from the hypocotyl knee and is an overgrown part of the main stem. In the root neck, buds are laid, from which new stems are formed. With age, the crown deepens into the soil, sometimes going to a depth of 7-10 cm, thereby protecting plants from the cold in snowless winters.
Nodules develop on the roots of alfalfa, which determine the ability to nitrogen fixation. Under irrigation conditions in Central Asia, three-year-old alfalfa plants are able to accumulate 300-400 kg/ha of nitrogen.
In the Non-Chernozem zone, the roots are able to reach a depth of 3 m. Usually they cannot penetrate the podzolic horizon, therefore they are located mainly in the arable layer. This feature is taken into account when choosing a field for sowing alfalfa and the method of tillage, which should include plowing with deepening. At the first sowing in the field of crop rotation, the seeds are treated with bacterial preparations, for example, nitragin or rhizotorphin, otherwise nodules on the roots are not formed, and the plants die for 2-3 years of life.
Aboveground part
The stem is herbaceous, strongly branched, green in color, sometimes with anthocyanin in the lower part. There are 10-20 internodes on the stem. In the first year of life, one alfalfa plant forms 3 stems, in the second year – 15-17, the third – over 20. Plant height in the first year is 30-50 cm, 2-3 – more than 1 m. The share of leaves in the first year is 50% of the mass of the above-ground part, 2-3 – about 40%.
The leaf consists of a stipule, petiole and three leaflets, planted on short stalks, serrated in the upper part. The color is light green and dark green.
Inflorescence -many-flowered raceme, 1.5-8 cm long, cylindrical or capitate. Moth-like flowers, bisexual, located on short pedicels, at the base of which are two filiform bracts. The flower includes the calyx, corolla, stamens and pistil. Calyx green, five-toothed. The structure of the corolla of the flower is similar to the structure of the corollas of clover . The number of stamens is 10, 9 grow together to form a stamen tube. The corolla is bright purple or light purple. Cross pollination.
The fruit is a multi-seeded bean, yellow, brown or brown in color, rolled up in 0.5-4 turns.
Seeds are reniform-curved, pale yellow or yellow-brown in color. Weight of 1000 seeds 1.5-2.7 g.
The color of the flowers and the shape of the fruit are characteristic species and varietal features of alfalfa.
Medicago falcata
The bush is sprawling, the stems are semi-recumbent or erect, covered with hairs. The root system is strong, it penetrates to a depth of more than 4 m. Lateral roots are long, horizontally branching.
Unlike alfalfa, yellow alfalfa plants are undersized. The root neck is larger and lies deeper than that of alfalfa. Leaves trifoliate, slightly pubescent. The flowers are yellow, collected in a dense shortened brush. Crescent-shaped beans, brown or black. Weight of 100 seeds 0.9-1.2 g.
Biological features
Temperature requirements
Seed germination begins at a temperature of 1-3 °C, the optimum temperature for germination is 18-20 °C. Seedlings withstand frosts down to -6 °C. In winter, with good snow cover, plants tolerate frosts down to -30 … -40 °С.
The most resistant varieties to negative temperatures come from mountainous regions and from areas with severe winters. Winter-hardy varieties of alfalfa are distinguished by a flattened rosette of leaves, in less winter-hardy varieties it is erect, and in medium-hardy varieties it is semi-raised. In terms of frost resistance, alfalfa is superior to red clover .
Winter hardiness strongly depends on the time of the last mowing. The last cut should be carried out 30-45 days before the onset of stable frosts, so that the plants have time to grow, form a rosette and accumulate an adequate supply of nutrients.
In the Non-Chernozem zone, liming the soil significantly increases the winter hardiness of alfalfa. In spring, regrowth begins at a temperature of 7-9 °C. In the first half of summer, at an average daily temperature of 22-23 °C, the period from the growth of the aerial part to the onset of flowering is 42 days, in the second half of summer, that is, by the time of the third and fourth cuttings, it is approximately 55 days. The sum of positive temperatures required from regrowth to the beginning of flowering for alfalfa is 800 °C.
Moisture requirements
Alfalfa is a drought-resistant plant, but responsive to moisture. Drought resistance is determined by a very powerful, deep-penetrating root system, which consumes moisture not only from the soil, but also from the subsoil layers. Alfalfa is a typical mesophyte, that is, for good growth of the aerial part, sufficient moisture supply is necessary; in terms of water consumption, it is second only to rice.
During germination, seeds absorb water up to 100% of their own weight. Alfalfa is demanding on soil moisture and is resistant to atmospheric drought. The optimal moisture content of a meter layer of soil, necessary to obtain a high yield of hay, is 80% of the lowest moisture capacity, therefore, with forage crops, it is recommended to carry out abundant watering after each mowing. With seed culture, they strive to maintain moderate soil moisture.
The transpiration coefficient is 700-900.
Yellow alfalfa is somewhat more drought tolerant than field alfalfa. Alfalfa blue hybrid is able to withstand flooding by hollow waters up to 10-12 days, yellow and yellow hybrid – up to 25-30 days.
Light requirements
Alfalfa is a long daylight plant. The yield of green mass and seeds of various varieties of alfalfa is higher with a 20-hour day length than with a natural or shortened (10 hours) (All-Russian Plant Research Institute).
Alfalfa is more photophilous than red clover , therefore, when oversown under the cover of well-developed grain crops, it thins out more.
Soil requirements
Alfalfa prefers fertile, loose and cultivated soddy-podzolic, well-aerated chernozem, chestnut, gray forest soils. It can grow on sandy, clay and alkaline soils.
Poorly tolerates the close occurrence of groundwater, stony and gristly soils. Does not tolerate highly acidic soils. At pH 5, nodule development almost does not occur, and in single nodules, bacteria do not fix nitrogen from the air. Optimal acidity pH 6.5-7.
Alfalfa is characterized by salt tolerance, which is:
- for chloride ion: at the age before sowing – 0.20%, in the budding phase – 0.60%, after the first mowing – 0.60%;
- for sulfate ion: during the budding period – 0.90%, after the first cutting – 0.90%.
Chloride ions have a more negative effect than sulfate ions at equal concentrations, the negative effect of carbonate ions exceeds the effect of chloride ions.
When sowing alfalfa on highly saline soils with a pH of more than 8-8.2, pre-washing is carried out with a large amount of water.
Plant nutrition
Alfalfa is distinguished by a large removal of nutrients from the soil, which is associated with a high yield of above-ground mass, characterized by a high protein content.
For the formation of 1 ton of hay, 6 kg of P2O5 17-20 K2O are consumed, as well as a lot of calcium and magnesium.
In some cases, alfalfa responds well to the application of sulfur fertilizers.
Vegetation
Alfalfa is a spring plant. In the year of sowing, it gives a crop of seeds or 2-3 hay cuttings.
Only one stem grows from a seed. New shoots (stems) develop from buds located on the root collar. Stems live no more than one year, with multi-cutting use – several weeks. With the death of old shoots, a part of the branching roots usually also dies off. New shoots cause the formation of new thin lateral roots.
In the first year, the plants mainly develop the underground part, reaching 40-60 cm in depth during the first months of the growing season, in the second and subsequent years of life – the aboveground.
Vegetative regeneration depends on the stability and vitality of the root collar and the buds located on it, therefore, when grazing it with animals or mowing, it is necessary to monitor the preservation of the root collar.
Alfalfa creates a very large leaf area: per 1 ha with an average plant development, the leaf area is 50 ha.
The duration of vegetation from germination to seed ripening in the first year of life is 130-140 days, in the second and subsequent years – 110-120 days.
Vegetation phases in the first year of life and the timing of their onset after sowing:
- seedlings – 10-12 days;
- branching – 35-40 days;
- budding – 61-65 days;
- flowering – 75-80 days;
- maturation – 130-140 days.
With summer sowing, seedlings appear on the 7-8th day, and branching occurs on the 22-25th day.
Vegetation phases of alfalfa in the second and subsequent years of life:
- regrowth;
- stalking, or branching, – 26-28 days;
- budding – 40-42 days;
- flowering – 50-52 days;
- bean formation;
- browning of beans, or ripening, – 115-120 days.
Flowering stretches for about 2-3 weeks, which leads to uneven seed ripening.
Plants grow well at an average daily temperature of 7 °C. Therefore, the growing season lasts from early spring to late autumn. The period from regrowth to the beginning of flowering usually does not exceed 40 days. Under favorable growing conditions, alfalfa can grow in one place for a long time. So, in Turkmenistan, it can grow in one field up to 20-30 years. Usually, the duration of use in field crop rotations is 2-3 years, in fodder – 3-4 years, in hatching fields – 5-6 years.
Crop rotation
In field crop rotations of the steppe zone, alfalfa is usually sown under the cover of spring grains of group I , less often – under millet, Sudanese grass or in the aisles of corn. In cotton-growing areas, it is sown without cover. The choice of a place in a crop rotation is determined by the specific conditions and the planned use.
Winter grain crops are of little use, so when sown under their cover, alfalfa is strongly oppressed.
For alfalfa, in order to obtain high yields of hay and seeds, it is necessary to allocate fields clean from weeds, fertile and well supplied with moisture.
In the conditions of rain-fed agriculture in the steppe zone , cereals that go through black fallow, corn, oil flax, melons and gourds can serve as good predecessors of alfalfa . Sugar beet is a poor predecessor, as it dries out the deep horizons of the soil. Under irrigation conditions, alfalfa can be placed on any predecessor.
In the Non-Chernozem zone, in special fodder crop rotations, it is grown in hatching fields with a use period of 3-4 years.
Fertilizer
Alfalfa is characterized by a large removal of phosphorus, potassium, calcium and magnesium from the soil.
It is responsive to the application of organic fertilizers under the cover crop. For example, the introduction of 20 t/ha of manure under cover barley increases the yield of alfalfa hay by 75% (the former Don Experimental Station), when 45 t/ha of manure is applied under cover winter rye, the yield of alfalfa hay mixture increased by 1.3 t/ha (Kazan Agricultural Institute).
Manure is introduced into a fallow for winter crops or industrial crops based on the use of alfalfa after the effect of manure. In the steppe zone, the recommended rate of manure application is 15-20 t/ha, in areas of sufficient moisture – 25-40 t/ha.
Highly saline soils gypsum and apply organic fertilizers. For example, the application of 4–5 t/ha of gypsum and 20–30 t/ra of manure provided an increase in crop yields in the crop rotation by 20–60%, including alfalfa hay by 1.1 t/ha.
Alfalfa is sensitive to phosphorus nutrition in the early period of development, especially in the first month of life, which also has a positive effect on development in subsequent years. Recommended application rates for mineral fertilizers P 45-60 K 45-60 (according to other recommendations N 30-45 P 60-90 K 60-90 ), for alfalfa grass mixtures – N 90 P 60 K 30 . On chernozems, it is recommended to apply 200-300 kg/ha of superphosphate, under irrigation conditions – at least 300 kg/ha of superphosphate, 100 kg/ha of potash fertilizers. Doses of phosphorus can be reduced when its content in the soil is more than 17 mg/100 g.
Nitrogen fertilizers are recommended for poor soils. They are introduced in early spring in cold weather, when nodule bacteria are not yet developed, in an amount of up to 30 kg/ha,
When sowing, row application of granular superphosphate together with seeds is recommended at a rate of 50 kg/ha, or P 10-30 .
Highly effective pre-sowing treatment of seeds with molybdenum micronutrient fertilizers per 1 hectare norm of seeds is 100 g of ammonium molybdate (ammonium molybdate), diluted in 400 ml of water. This treatment is especially important when planting in soils with a low content of molybdenum, such as sod-podzolic and gray forest. Pre-sowing treatment of seeds with molybdenum and boron microfertilizers increases the germination of seeds and increases the yield of green mass by 17% (Shchedrina D.I., Voronezh Agricultural University).
After grain crops, tillage for alfalfa includes stubble plowing, then, after 2-4 weeks, plowing with a plow with a skimmer to a depth of 25-30 cm. by 5-8 cm, after the growth of weeds – plowing with alignment of breakup furrows and dump ridges. In the case of early plowing, semi-fallow processing is possible.
An increase in plowing depth from 18 to 25 cm contributes to an increase in hay yield by 0.3 t/ha (Krasnokutsk Experimental Breeding Station of the Research Institute of Agriculture of the South-East, Saratov Region), and from 20 to 30 cm in the first year of use – by 0.7 t /ha, or from 34.7 c/ha to 42.2 c/ha, in the second year – by 0.2 c/ha, or from 27.6 c/ha to 30.4 c/ha (Bezenchuk Experimental Station , Samara Region).
Pre-sowing tillage when sowing in early spring under the cover of grain crops consists in harrowing in 2-3 tracks. If Sudan grass, millet or other late-sown crops are used as cover crops, then before sowing, 2-3 cultivations per 3-5 cm are performed with simultaneous harrowing.
Pre-sowing treatment during summer coverless sowing includes layer-by-layer cultivation with harrowing: the first to a depth of 12-14 cm, the second – 8-10 cm, the third – 3-4 cm. In dry conditions, after each cultivation, the field is rolled. During summer sowing, surface tillage can be carried out immediately after harvesting winter crops for green fodder, including disking, cultivation and rolling.
In the steppe regions, soil rolling is of great importance before sowing. According to the data of the former Krasnokutsk State Breeding Station, soil rolling before and after sowing increased seed germination by 30%, or from 78 plants per 1 m2 to 102 plants per 1 m2.
In Central Asia, under irrigation conditions, in addition to autumn deep plowing, spring plowing of structureless clayey soils caking during the winter or deep loosening with chisel with simultaneous harrowing is sometimes required. An important method of soil preparation on irrigated lands is field planning, which ensures uniform distribution of irrigation water over the area.
In fields littered with perennial weeds, their rhizomes are combed out before plowing and removed outside the site.
Pre-sowing seed treatment includes cleaning from impurities using grain cleaning machines. In the presence of an admixture of dodder seeds, special cleaning is used with special machines. Pre-sowing treatment may also include treatment with bacterial preparations and microfertilizers.
For dressing seeds against diseases (ascochitosis, fusarium, gray rot, anthracnose, bacteriosis, seed mold), TMTD, Aktamyr preparations can be used.
In the southeast, in arid areas, the seeding rate for alfalfa is 8-12 kg/ha, in humid areas – 12-16 kg/ha, with irrigation – 14-16 kg/ha, in the Non-Chernozem zone – 14-18 kg/ha.
Sowing is carried out with grain-grass seeders, for example, СУТ-47, СЗТН-47, СЗТ-3,6 to a depth of 2-3 cm in the usual ordinary way. When sowing under the cover of spring cereals, sowing is carried out early – simultaneously with the sowing of grain crops. When sowing under the cover of corn or sorghum, the cover crop is sown first, then alfalfa. The seeding rate for corn is 25-30 kg/ha, sorghum is 15-20 kg/ha.
If sowing is carried out with conventional drills, it is done across the rows of the cover crop. The seeding rate in this case is 17-20 kg/ha, or 9-9.5 million viable seeds per 1 ha.
In areas of insufficient moisture, a half-cover sowing method can be used, that is, with an incomplete seeding rate of the cover crop.
Crop care
On undercover crops of alfalfa, the cover crop is harvested at the optimum time. Forage cover crops should be cut for green fodder rather than hay. Cereals are harvested by direct combining at a cutting height of at least 12-14 cm (according to other sources, at least 20 cm) with simultaneous removal of chopped straw. A low cut worsens the conditions for overwintering of plants, leads to thinning of crops.
With sufficient moisture in the soil, it is recommended to fertilize alfalfa with phosphorus and potash fertilizers in early autumn at the rate of 100-200 kg/ha of superphosphate and 50-100 kg/ha of potassium salt, or P45-60K45-60, to increase the frost resistance of plants.
In winter, snow retention is carried out in the steppe and forest-steppe regions.
The intensity of spring regrowth and frost resistance depend on the period and height of autumn mowing of alfalfa, which should be carried out at a height of 7-8 cm no later than 30-40 days before the onset of stable frosts.
With a coverless alfalfa culture, crop care includes rolling the soil after sowing, breaking up the soil crust with light ring rollers or rotary hoes, and controlling weeds, pests, and diseases. Weed control in alfalfa fodder crops or grass mixtures is usually reduced to mowing at a plant height of 15-20 cm. The cutting height is set so that the growth point of cultivated plants is not damaged. Also on clean crops of alfalfa against annual cereal weeds, pre-sowing soil herbicides can be applied for cultivation; against dicotyledons – spraying with permitted herbicides is carried out in the phase of 2-3 true leaves.
In early spring, crops of alfalfa or alfalfa grass mixtures are harrowed across the rows. Loosening the soil with disc implements can contribute to the rejuvenation of the old herbage. In the steppe zone, good results are obtained by the autumn splitting of crops, which ensures the accumulation of moisture during the autumn-winter period.
Diseases
Brown leaf spot
Brown leaf spot affects the leaves, stems and beans of alfalfa. The disease manifests itself in late spring on the lower leaves, then quickly covers the entire plant. Affected leaves fall off. To combat, seed treatment is carried out with 80% TMTD, in autumn or spring – harrowing across the rows, early first mowing before the start of sporulation of the fungus, treatment of crops during the growing season with a 1% Bordeaux mixture solution.
Ascochitosis
Ascochitosis affects leaves, stems, flower stalks, beans and seeds of alfalfa, sometimes the upper part of the root, which leads to its cracking. To combat, pollination of crops with sulfur is carried out, plant remains of diseased plants are destroyed (burned), plowing of old-growth alfalfa fields and early mowing for hay. Also, the use of phosphorus-potassium fertilizers reduces the infestation of the herbage by 3.5-4 times.
Rust
Alfalfa rust affects the leaves, stems, pedicels of alfalfa. It leads to a rapid fall of the leaves, the affected stems are easily broken. With a moderate spread of the disease, the yield is reduced by 30%. To fight, they carry out early harvesting for hay, the destruction of weeds; when cultivated for seeds – dusting with sulfur.
Wilt
Bacterial wilt, or wilt, affects the vessels of the root and stem, as a result of which the plants acquire an oppressed appearance, become dwarfed, the leaves turn yellow, and turn brown in hot weather. The disease is very harmful. For the struggle, the correct crop rotation, the destruction of plant residues, and the maintenance of a high agrotechnical background are important.
Pests
Alfalfa bug
The alfalfa bug damages the leaves, buds and flowers of alfalfa, which quickly fall off. With the defeat in the early period, the upper part of the shoot dies off. To fight, new alfalfa crops are placed at a considerable distance from old alfalfa, sowing is carried out under the cover of cereal crops, stubble is mowing at a low cut, treated with Bitoxibacillus, Fastak, Altalf, Tsunami, Alpha Tzipi, Alfas, Rotalaz, Fastkord, Caesar, Picket, Decis, Diazinon, Bi-58 New, Danadim, Rogor S, Di-68, Nugor.
Phytonomus
Phytonomus, or leaf alfalfa elephant. Beetles begin to feed on alfalfa leaves in early spring, the larvae cause great damage to the apical buds, buds and flowers. For struggle, disking is carried out in 2-3 tracks in early spring, mowing of alfalfa for hay, the use of alfalfa for seeds for two years in a row is not allowed. In the fight against phytonomus larvae, biological preparations can be used, for example, entobacterin, boverin, dendrobacillin at 2-3 kg/ha.
Tychius weevil
Tychius weevils are common in all regions of alfalfa cultivation. Beetles after overwintering in spring feed on leaves, then buds, buds and flowers. The damage caused by Tychius increases sharply with a lack of rainfall in early spring. For struggle, alternate the use of alfalfa for hay and for seeds.
Alfalfa seed-eater
Seed-eater females lay their eggs inside green seeds when fruit is set. The larvae emerging from the eggs eat away the contents of the seed. Over the summer, the alfalfa seed-eater is able to give 1-3 generations, so the defeat of seeds can be in the first and second cuts. For the fight, seeds are cleaned, alfalfa crops are disked, and permitted chemicals are used.
Nodule weevil
Nodule weevils damage alfalfa plants from germination and during regrowth. Weevil larvae damage roots and nodules. To fight, they are treated with permitted chemicals in early spring, before laying eggs by beetles.
Meadow moth
To combat the meadow moth, crops are sprayed with Lepidocid, Bitoxibacillus, Diazinon, Karbofos, Karbofot, Fufanon, Kemifos, Bunchuk, Zolon, Fort, Sharpei.
Harvest
Pure crops of alfalfa are usually harvested for haylage, forage obtained by high-temperature drying, hay leaves.
The maximum fodder mass yield is achieved when harvesting in the flowering phase, while the maximum quality is achieved in the budding phase. Therefore, harvesting starts in the period from the end of the budding phase (early mowing) to the beginning of the flowering phase (moderate mowing). Later harvesting periods lead to a deterioration in the chemical composition of plants and a decrease in the quality of hay.
Hay harvesting is carried out by hay harvesters or machines that flatten stems, for example, KPF-1.8 and KPV-3.0. For raking hay and forming windrows, side rakes GBU-6.0 or wheel-finger rakes GVK-6.0 are used. Hay is pressed from rolls using PSB-1.6 and PPV-1.6 balers. Bales of pressed hay are transported to a place of permanent storage.
In the steppe and forest-steppe zones with natural moisture, mow alfalfa 2-3 times, with irrigation – 4-5 times. Hay can be harvested with mower-conditioners, for example, E-301, E-302, E-303, hay flattening reduces the drying time by 30%. Also, the tedding of the mowed mass contributes to the acceleration of drying.
The method of active ventilation and pressing reduces the loss of hay from shedding leaves, improving its quality by increasing the content of protein and carotene. The method provides for additional drying of the dried after flattening and tedding mass with a moisture content of 35-45% in stacks or hay storages to a moisture content of 15-17%.
When using alfalfa for haylage, it is mowed with flattening in the flowering phase. Cleaning begins at a humidity of at least 60%.
For the purpose of harvesting vitamin-herbal flour and granules, mowing is carried out at the beginning of budding. The green mass is dried and processed. To reduce the loss of carotene, herbal flour and granules are stored in plastic bags in dark rooms at a humidity of 10-12%.
The Voronezh Agricultural University has proposed a technology that provides for the preparation of hay leaves, which in terms of nutritional value is not inferior to more expensive grass meal and granules (Shchedrina D.I. et al., 2002).
Features of cultivation under irrigation
Alfalfa and alfalfa mixtures in the steppe zone are often grown under irrigation in fodder crop rotations or in hatching fields.
The seeding rate of alfalfa seeds in its pure form, as a rule, is 15 kg/ha, in two- and three-component grass mixtures 6-8 kg/ha, in a four-component mixture – 4-5 kg/ha.
When choosing grasses and determining the composition of grass mixtures for floodplain lands, the duration of their flooding is taken into account. Alfalfa blue hybrid can withstand flooding for 10-12 days, variegated and yellow hybrid – 20 days, yellow – 25-30 days.
The removal of nutrients with a planned yield of 50 t/ha of green mass by alfalfa grass mixture is 380 kg/ha of nitrogen, 800 kg/ha of phosphorus and 390 kg/ha of potassium. Therefore, it is recommended to apply N30-45 annually for each cut (total N180), P60-90K60-90. Nitrogen fertilizers are recommended to be applied with irrigation water, phosphorus-potassium fertilizers – in autumn for the main tillage, on floodplain lands – after the flood.
The irrigation regime is determined by the amount of moisture in the soil and the amount of precipitation during the growing season. The optimum soil moisture in a 70 cm layer should be 70-80% of the lowest moisture capacity.
Under irrigation conditions, on plots prepared for sowing alfalfa, reserve irrigation is often carried out with a rate of 2000 m3/ha of water, on saline soils – leaching. Spare irrigation contributes to an increase in the yield of alfalfa hay by 1-1.5 t/ha.
In the year of sowing alfalfa, irrigation can also be carried out at 600-800 m3/ha. The first watering of the first year of life of alfalfa is given in the period of appearance of 6-7 true leaves. The following year, harrowing is carried out to remove stubble and slightly loosen the topsoil. When irrigating, irrigation is usually carried out from regrowth to the first cut, which, for example, in the Hungry Steppe increases hay yield by 40%.
The first watering in a dry spring is done in early May, then after each mowing. In very dry years, watering is carried out between cuttings. In years with average moisture, 3-4 irrigations are usually carried out at 500 m3/ha. On light-textured soils, the irrigation rate is reduced to 300 m 3 /ha, but the number of irrigations increases. After mowing, watering is done no later than 3-5 days later.
In the case of alfalfa cover cultivation, the first irrigation is done immediately after the cover crop is harvested with an irrigation rate of 500-600 m3/ha. With coverless sowing in spring, the first watering is done 40-50 days after germination with an irrigation rate of 300-400 m3/ha, then – 500 m3/ha after each mowing.
Alfalfa of the second year of life is watered after 10-14 days from the beginning of spring regrowth. It is also recommended to irrigate 5 days before mowing for hay to avoid drying out the soil during the harvesting period and to ensure the rapid growth of the mowed plants. After mowing and hay harvesting, the field is harrowed with heavy harrows in two tracks.
In irrigated areas, the amount of irrigation depends on the depth of standing groundwater, the mechanical composition of the soil, the topography of the site, the method of irrigation and the moisture reserves in the soil. In all cases, soil moisture in the cultivation of alfalfa for hay in a meter layer of soil should be at least 70-75% lowest moisture content. So, at soil moisture of 55% of the lowest moisture capacity, the hay yield was 7.3 t/ha, and at 75% – 8.9 t/ha (Bezenchuk experimental station, Samara region).
Watering is carried out during the period of alfalfa growth after 15-25 days and during the period of intensive growth – after 8-15 days.
Irrigation and fertilization is effective when the herbage density is at least 300-400 plants per 1 m2 . According to the data of the Research Institute of Agriculture of the Central ChP im. V.V. Dokuchaev (Voronezh region), the yield of hay grass mixture of variegated alfalfa, awnless brome and meadow fescue under irrigation conditions was 13.9 t/ha.
Growing alfalfa for seeds
For seeds, alfalfa is grown in seed farms in specialized crop rotations, in non-specialized grass seed farms – in open areas, hatching fields, in soil -protective or fodder crop rotations. Sowing alfalfa for seeds is recommended to be placed on the southern slopes.
In order to prevent the growth and lodging of alfalfa seed crops, especially in wet years, it is recommended not to place it in very fertile or well-fertilized fields. It is better to allocate medium-fertile soils with a humus content of up to 3%, but provided with phosphorus, potassium, calcium, boron and molybdenum, for seed plants.
Soil cultivation for seed crops of alfalfa is similar to that for fodder crops. The main task is to provide protection against weeds, for example, with improved fallow or semi-fallow.
Phosphorus-potassium fertilizers are applied based on the planned harvest, in general, the recommended rate is P 60 K 60 . In addition to molybdenum fertilizers, alfalfa responds well to boric fertilizers , which help to improve fertilization and seed setting. For example, in the conditions of the forest-steppe, the joint application of boron and molybdenum to the soil gave an increase in seed yield of 90 kg/ha (Shchedrina D.I.).
In the spring, early spring harrowing and leveling of the fallow are carried out, soil herbicides are applied for pre-sowing cultivation, for which beet cultivators USMK-5.4 are better suited to a depth of 3-4 cm. Before and after sowing, rolling is carried out: before sowing – with smooth rollers, after – ringed ribbed.
The sowing method is a coverless wide-row with a row spacing of 60-70 cm or a wide-row-tape according to the schemes of 60×15 cm or 70×15 cm.
In the arid steppe, sowing is carried out in early spring simultaneously with the sowing of early grain crops, which makes it possible to obtain seeds in the year of sowing. In conditions of unstable and sufficient moisture, alfalfa is sown in spring or summer.
Seeding rate of seeds is 1.5-2 kg/ha or 2-3 kg/ha with 100% sowing suitability (0.25-0.5 million units/ha), or 10-25 plants per 1 m 2 . With summer coverless sowing, the rate is increased by 15-20%. The depth of sowing seeds on loamy chernozems is 0.5-1.5 cm, on other soils – 2-3 cm. The sparse placement of plants contributes to the formation of productive stems as a result of improved photosynthesis and root nutrition, better illumination. In wide-row sparse crops with a row spacing of 45 cm and a seeding rate of 0.25-0.5 million pcs/ha of germinating seeds, 160-200 generative stems per 1 m 2 are formed with 10-15 inflorescences in each, which is more favorable for the work of pollinators .
Crop care includes breaking up the soil crust before germination, controlling weeds, diseases, and pests. Crops are fed with phosphorus-potassium fertilizers in autumn and early spring.
On coverless early spring wide-row crops, in the first year of alfalfa life, to control weeds, harrowing is carried out by seedlings, in the second and subsequent years – disking in early spring until regrowth. Also, inter-row cultivation and hilling are carried out annually. To prevent sprouting and lodging, attention should be paid to the selection of resistant varieties, hilling and autumn pruning of roots. Horizontal pruning in autumn or spring before regrowth is done to a depth of 25 cm. Starting from the 2nd year of alfalfa life, pruning is especially effective in years of sufficient moisture, and also contributes to the mineral nutrition of plants. Cutting with flat cutters increases the rate of growth of young roots, increases their absorption capacity, increases the period of use of the testes and their productivity. It is advisable to perform pruning in the fall, since the resulting cracks contribute to the accumulation of moisture in the autumn-winter-spring period. However, pruning is not carried out in dry years, as this reduces the seed yield.
Spring disking of crops before regrowth reduces the number of alfalfa pests. With a high number of pests or signs of disease, the crops are treated with approved preparations.
For better pollination of seed alfalfa crops, it is recommended to use leaf cutter bees or honey bees. So, when 2-7 honey bees or 1-5 leaf-cutting bees work per 1 m 2 of alfalfa seed herbage, subject to the cultivation technology, the seed yield for 2 years was 320-1000 kg / ha (Gagarinsky special farm, Kalashnikov collective farm, Levokumsky district, Stavropol Territory). If insects open more than 90% of the formed flowers, they consider that the crops are provided with pollinators very well, 71-90% – good, 50-70% – satisfactory, less than 50% – bad. With very good and good pollination, the field of seed alfalfa looks gray, the smell of flowering plants is not felt. On the contrary, a small opening of flowers by the end of the day and a specific aroma indicate a lack of pollinators.
When preparing the seed plants for harvesting, specific weeding and mowing of the edges of the plots are carried out.
Higher seed yields are usually obtained from the first cut. Direct combining begins when 90-95% of the beans of the herbage are browned. To reduce losses, harvesters and vehicles are sealed. Seed harvesting by direct combining can be carried out with preliminary desiccation of the herbage with magnesium chlorate at the rate of 18-20 kg/ha or reglonal at 4-5 kg/ha. Desiccation is performed when 80-85% of the beans are browned, and harvesting is done 6-7 days after processing.
In the conditions of the steppe and forest-steppe zones, seeds can be obtained from the first, one and a half or second mowing. If the weather in May was hot and dry, it is more advisable to collect the seeds from the first cut. If cool and humid weather has set in, and pests are very common in crops, it is recommended to cut seed alfalfa in the budding phase or 7-10 days before it occurs. Thus, when mowing in the budding phase, seeds are obtained from the second mowing, in the second – from one and a half.
The reason for low seed yields in the forest-steppe zone is usually an excess of precipitation in the flowering phase, which causes overgrowth and lodging of crops, as well as a deterioration in the work of pollinators. The optimal conditions for obtaining a high yield of alfalfa seeds of the 2nd year of life are formed when no more than 250 mm of precipitation falls during the growing season, and most of them should fall during the period from regrowth to flowering (Shchedrina D.I., Voronezh Agricultural University). The number of days without precipitation during the flowering period should be 60%, the hydrothermal coefficient is 0.6-1.0, the optimal average daily air temperature in this phase is 21-22 ° C, in the fruiting phase 19-20 ° C, relative air humidity – no more 70%.
The second reason for low seed yields is the lack of pollinating insects. Therefore, seed crops are recommended to be located on the southern slopes of hatching fields near forest belts, beams and ravines in elongated sections of 20-25 hectares, since wild pollinating bees usually fly from their nesting sites at distances of no more than 200-250 m. The number of pollinating insects also depends on weather conditions and varies from 286 to 2320 pieces/ha. To conserve insect habitats, natural forage lands are not plowed up and pesticides are not used at nesting sites. For the reproduction of wild pollinating insects, it is recommended to create special micro-reserves that are not used for arable land and livestock grazing. To create conditions for the settlement of insects in alfalfa crops, crops of the first year of life along the perimeter are sown with strips of honey plants, for example,sainfoin or phacelia, in strips of 6-8 meters. In addition, strips of grasses are placed inside the seed plots, where nests of wild pollinating insects appear. Other flowering fields should be located at some distance so that during the flowering period of alfalfa they are not distracted by other areas. For additional pollination, artificially bred leaf-cutting bees of 20-30 thousand pieces per 1 ha can be used, which can increase the yield of alfalfa seeds by 2-3 times.
One of the reasons for the low collection of seeds under production conditions is losses during harvesting, because by the time of harvesting alfalfa has a powerful vegetative mass with high humidity, while seeds account for only 2-10% of the mass, which are also very small and fluid. This is due to the difficulty of isolating seeds from a heap. Therefore, a technology was proposed that provides for only the collection of above-ground mass in the field, and threshing, cleaning and drying of seeds – at the edge of the site or a special stationary point. According to tests conducted by the Voronezh Agricultural University, pneumatic inertial separators are the best at separating seeds from a non-winnowed heap. Also, the sorting line provides for additional threshing of unthreshed parts of plants. The proposed technology was tested in the Berezovskoye educational farm of the Voronezh Agricultural University.
Seed production under irrigation
Seed plots are assigned to grass stands of the second or third year of life of alfalfa plants at a density of 50-70 plants per 1 m2. On soils with deep groundwater or low precipitation during the winter period, water-charging irrigation is carried out at 1500-2000 m3/ha. Seeds on such soils are obtained from the first mowing.
In autumn or early spring, the testicles are fertilized with 400-500 kg/ha of superphosphate and 100-150 kg/ha of potassium salt with simultaneous harrowing with heavy toothed harrows.
Weeds are removed from the plots, primarily dodder, pink mustard, humai. Against phytonomus, one or two treatments with phosalone (2.5 kg/ha) or actellik (1.5 kg/ha) are carried out.
On meadow-marsh soils with a close occurrence of groundwater to the soil surface, high seed yields are obtained from the second mowing.
Vegetative irrigation of seed crops is done during the period of regrowth and in the budding phase when seeds are obtained from the first cut or in the phase of the beginning of flowering when seeds are obtained from the second cut. Irrigation rate is 950-1000 m3/ha.
Seed harvesting begins when 70-80% of the beans are brown, located on normally developed stems. Cleaning is carried out in a two-phase way. First, alfalfa is mowed with monitor headers or mowers with installed swathers. After the mass has dried, that is, approximately 5-6 days after mowing, the dried mass is removed.
To improve the harvesting of seed plants of alfalfa, as well as clover and cereal grasses (timothy grass, fescue, hedgehogs), the СК-5 Niva combine uses the 54-108A device – a grater device, which, together with a threshing drum, ensures wiping the seeds of legumes from pizhina.
A heap comes out of the combine, which includes seeds and dilapidated beans. The heap is passed through special clover graters to separate the seeds from the beans. Then the seeds are separated from impurities using grain cleaning machines and electromagnetic sorting ЭМС-1. The moisture content of seeds before laying for long-term storage should be no more than 13%.
Technology proposed by the Volgograd Agricultural Institute
The Volgograd Agricultural Institute has proposed a technology for obtaining 800-900 kg/ha of alfalfa seeds. Subject to agricultural technology, seeds can be obtained from one site for 3-4 years. Therefore, the seed plot is recommended to be located outside the crop rotation.
For autumn plowing, they are brought into stock for 3-4 years P180-200K150-200. Soil cultivation is normal. Sowing method is row or wide-row two-line 70×15 cm. Seeding rate is 2-3 million/ha of viable seeds, or 4-6 kg/ha of seeds with 100% sowing suitability.
Irrigation mode: the first watering is done in the branching phase, the second – in the budding phase, the third – during the seed filling period. Prior to flowering, the moisture content of a meter layer of soil should be maintained at the level of 75% of the lowest moisture capacity, after flowering – 65%.
In the budding phase, top dressing is done at the rate of 60 kg of nitrogen per 1 ha.
Harvesting is carried out in two phases, starting when 70-75% of the beans turn brown. Alfalfa is cut into rolls, after 5-6 days it is threshed with a combine. Seeds are cleaned from foreign impurities and laid for storage.
Sources
V.V. Kolomeychenko. Horticulture/Textbook. – Moscow: Agrobiznesentr, 2007. – 600 с. ISBN 978-5-902792-11-6.
Horticulture/P.P. Vavilov, V.V. Gritsenko. Vavilov. ed. by P.P. Vavilov, V.S. Kuznetsov et al. – M.: Agropromizdat, 1986. – 512 p.: ill. – (Textbook and Tutorials for Higher Education Institutions).
Fundamentals of Technology of Agricultural Production. Farming and plant growing. Under the editorship of Niklyaev V.S. – Moscow: “Bylina”, 2000. – 555 с.