Clover is a fodder crop related to perennial leguminous grasses. In production, red clover is of primary importance.
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Economic importance
Clover is used to make hay, highly nutritious silage, haylage, grass meal, pellets and briquettes.
Thanks to nodule bacteria, clover has the ability to fix nitrogen.
“We can assume that 1 hectare of good clover, fertilized with potassium and phosphorus, can provide 150-160 kg of nitrogen per year (we consider both clover hay nitrogen and nitrogen of root residues). This means that 200 thousand hectares of clover, with the right culture, can bind 30-32 thousand tons of nitrogen per year, that is, as much as a nitrogen plant.”
D.N. Pryanishnikov. Modern issues of sideration. – Tr. VIUA. M.: Ed. VASKHNIL, 1936.
Within 2 years, clover is able to accumulate in the soil up to 6-9 t/ha of root and crop residues (in terms of dry matter), and 150-200 kg/ha of nitrogen.
The clover layer serves as an excellent predecessor for fiber flax, cereals, sugar beets, potatoes and other crops. Clover seeded fallow in terms of winter wheat yield is often not inferior to bare fallow. The introduction of clover into crop rotation helps to increase its productivity. With high yields of green mass, it clears the fields of weeds and increases soil fertility.
Clover can be used for grazing cattle, but only if mixed with cereal grasses, since feeding the green mass of one clover causes tympanum (bloating) in animals, which can lead to death. For pigs and poultry, single-species crops can be used.
Clover is often used in grass mixtures, for example, in hayfields – along with timothy and meadow fescue.
100 kg of clover hay contains 52.3 feed units and 8.2 kg of digestible protein. 100 kg of fresh grass – 22.8 feed units and 3.0 kg of digestible protein.
History of the crop
Clover was cultivated in ancient Greece and ancient Rome, but it became widespread in Europe in the 18th century with the transition to a fruit -shift farming system.
In our Russia, clover sowing began more than 200 years ago. The first experiments with clover were made by the Russian agronomist A.T. Bolotov at the beginning of the second half of the 18th century. At the beginning of the XIX century. it began to be systematically sown in the fields in Yaroslavl, Perm and other provinces. Some varieties bred at that time have not lost their significance in our time. Before the Revolution of 1917, clover sowing in Russia had a small distribution. So, at the beginning of the XX century. in the Yaroslavl province, clover was grown by 7.5% of peasant farms, and the area occupied by clover was 1.0% of all arable land.
In the year of the USSR, the sown areas of clover increased significantly.
Area of cultivation
Clover is cultivated throughout the world, with the exception of Africa.
Red clover is the leading fodder crop in field crop rotations in the forest-steppe and forest zones, which make up half of the territory of Russia. In the north, it is cultivated on the Kola Peninsula, in the Arkhangelsk region, the Komi Republic. Beyond the Urals – north of Tyumen and Krasnoyarsk. The southern border of clover sowing runs from somewhat north of Kharkov to Penza, Chelyabinsk and Kurgan; in Siberia – Omsk, Novosibirsk, Barnaul, Kyzyl, Irkutsk. Clover crops are found in the foothill regions of the Caucasus, the Urals and Altai.
In the period of the USSR, the sown area occupied by clover was 6.2 million hectares.
In the forest and steppe zones of Russia, clover ranks second among perennial grasses, behind alfalfa.
Yield
The yield of clover during the Soviet period was:
- in the Moscow region (Leninsky district) – 5-7 t/ha of hay;
- in Lithuania (state farm “Rambinas”, state farm “Stoni hsiai”, Silutsky district) – 6-8 t / ha of hay.
The yield of green mass of clover is 30-40 t/ha, hay – 5-7 t/ha, seeds – 150-300 kg/ha (Kursk Research Institute of Agro-Industrial Production). The maximum yield in state variety plots reaches 6-9 t/ha of hay.
Botanical description
Types of clover
The genus clover (Trifolium) includes about 300 species, of which 3 perennial and 3 annual species are used in cultivation.
Perennial species:
- red clover (Trifolium pratense L.), or red;
- hybrid clover (Trifolium hibridum L.), or pink, Swedish;
- creeping clover (Trifolium repens L.), or white.
Annual types of clover:
- crimson clover (Trifolium incarnatum L.), or incarnate;
- clover of Alexandria (Trifolium alexandrinum L.), or bersim;
- Persian clover (Trifolium resupinatum L.), or shabdar.
In field grass sowing, red clover is the most widespread. One-year-old clover is important as a fodder and green manure crop, but it is not widely used in our country.
Red clover
Red clover is a perennial plant that lives 2-4 years in the field.
Root system
The root system is well developed, consists of the main (tap) root and lateral roots. In the first year of a plant’s life, the roots quickly deepen into the soil. In the case of coverless sowing, often already on the 40th day after sowing, they penetrate to a depth of 20 cm, when sowing under cover, the rate of deepening slows down.
The rate of deepening of the root system depends on the intensity of illumination: the weaker the illumination of grasses, the slower rooting occurs. This pattern is taken into account when developing agrotechnical measures to prevent the thinning of seedlings of grasses sown under cover.
The root system continues to develop in subsequent years of life. The roots are able to penetrate to a depth of 200-230 cm, but their bulk is located at a depth of up to 30 cm. They account for up to 70% of the aerial part. Nodules first begin to develop on the tap root, then on the lateral ones. The formation of the first nodule corresponds to the appearance of the first true trifoliate leaf.
The root system is distinguished by the ability to reduce the main root. 2 months after sowing clover, the root neck of the central root is located at a depth of about 1 cm from the soil surface, while in the third year of life – at a depth of 3.8-4.3 cm. and freezing in winter.
Stem
The stems are pressed with whitish stripes, erect or ascending, rounded, hollow.
According to the number of internodes on the formed stems, red clover differs into the southern (early maturing, two-cut) type with the number of internodes up to 5-7, the spring type of development and a height of 50-100 cm and the northern (late-ripening, single-cut) with the number of internodes more than 7, the winter type of development and a height of 70-150 cm. The southern type is distinguished by greater foliage, smaller growth, and reduced winter hardiness. In the year of sowing, the southern type produces seeds, while the northern type forms only a basal rosette of leaves.
Single-cut clover has become widespread in the Non-Chernozem zone, the Omsk and Novosibirsk regions, and the Krasnoyarsk Territory. Two-cut – in the forest-steppe part of the Central Black Earth zone.
Leaves
The leaves are compound, trifoliate; the lower ones are located on a long petiole, the upper ones are shorter. The shape is ovoid, elongated-ovoid, elliptical. On leaf blades there is a characteristic white spot in the form of a triangle. The leaves of the early-ripening southern type of clover account for about 42-44% of the mass of the aerial part, and the late-ripening clover – about 40%.
Flower
The flower is small, includes a calyx, corolla, ovaries with a style and stamens. The calyx has five teeth, ten veins, greenish in color. Corolla purple, tubular. Stamens ten, nine of which are fused. Ovary superior, unilocular. The inflorescence is a spherical or elongated head. In the head, the number of flowers varies from 60 to 170, with an average of 100.
Cross pollination.
Fruit
The fruit is a single-seeded bean, sometimes two-seeded. Seeds are ovoid with a raised shoulder, flattened, yellow, brown or purple with a sheen. Weight of 1000 seeds 1.6-1.8 g.
Clover hybrid
Clover hybrid, or pink, differs from meadow clover in smaller sizes and pink heads. It is more hardy and tolerates winter frosts and spring frosts better than red clover.
Able to grow in pasture use in one place up to 6-8 years, in the field usually 3 years. Less demanding on soil acidity, can grow on clayey and waterlogged soils that are heavy in granulometric composition.
The aerial part grows well after mowing or grazing. Clover hybrid is usually used to create artificial hayfields, cultivated pastures for long-term use, as well as in fodder crop rotations in the Non-Chernozem zone.
Creeping clover
Creeping clover, or white, has a branching stem. Flower heads are loose, spherical in shape with a white corolla.
It grows well on moist clay soils, the most resistant of the clover species to the close occurrence of groundwater from the soil surface and flooding. In herbage it can grow up to 8-10 years. Resistant to trampling by livestock, grows back quickly after grazing. Not suitable for haymaking.
Creeping clover is considered one of the best pasture plants for the Non-Chernozem zone due to its high fodder quality, durability, and aftertaste. It is also suitable for grassing sloping lands with the threat of erosion processes.
The seeding rate in the composition of complex grass mixtures is from 3 to 6 kg/ha.
Biological features
Temperature requirements
Red clover is a plant of a moderately warm, humid climate, without sharp temperature fluctuations and a stable snow cover.
Seed germination of red clover begins at a temperature of 1-3 °C, optimal 10-20 °C. Shoots withstand frosts down to -8 … -10 °С. The maximum photosynthetic activity is noted at 25 °C. In autumn and early winter, plants of the first year of life experience photosynthesis at a temperature of -7 … -9 °С.
In clover sowing areas, winters with very severe frosts can lead to the death of plants, thinning of crops, and a decrease in yield and quality of hay. On the resistance of the root collar to the action of severe frosts, depending on the age and growing conditions of clover. At the beginning of winter, plants of the first year of life in the phase of the rosette can tolerate a temperature of -15 °C in the area of the root neck. In the second and third years of life, frost resistance usually decreases. From the second half of the winter period, the resistance of plants to low temperatures decreases.
At a temperature of -11 … -13 °C, second-year clover crops thin out by almost 50%. The lowest frost resistance occurs in the spring, when at a temperature of -8 … -8.5 °C, thinning reaches 40%.
The use of fertilizers improves frost resistance. According to the Department of Crop Production of the Moscow Agricultural Academy, when clover was frozen at a temperature of -12 … -13 °C, the proportion of living plants was:
control (without fertilizers) December 24 – 56%, February 28 – 60%, March 28 – 0%;
against the background of 40 t/ha of manure and N30P75K75 – 100% on December 24, 86.7% on February 28, 72.7% on March 28.
Frost resistance and winter hardiness decrease with a long-term lack of moisture in the soil, therefore, depending on weather conditions at the end of summer and autumn, it is possible to predict the loss of clovers from early spring frosts for timely action, such as rolling snow over the “snow crust”, which delays snow melting by 5-7 days or early spring fertilizing with mineral fertilizers.
The sum of active temperatures for the formation of a hay crop from regrowth to the first cut for the late-ripening type of clover is about 950 °C, for the early-ripening 800 °C; from post-cut regrowth to the second cut – 600-800 °C.
Moisture requirements
Red clover refers to moisture-loving plants. The total water consumption of late-ripening clover is 500-600 units, early-ripening – 400 units. For the formation of 1 kg of dry mass, the total water consumption is 400-600 liters.
Optimum soil moisture is 70-80% of the lowest moisture capacity. Clover does not tolerate excess moisture; if water stagnates for more than 10-12 days, it dies. During the growing season, the need for moisture is different.
Young plants are very sensitive to water deficiency: drought for 20 days causes the death of 50-60% of plants that have formed 1-2 true leaves. If a 20-day drought occurred after the formation of four true leaves, the death of plants was 20% (Department of Plant Industry, Moscow Agricultural Academy). This is due to the fact that plants with four true leaves are more developed and accumulate more reserve nutrients and the fact that lateral buds begin to form in the four-leaf phase; such plants are always highly resistant to adverse environmental conditions.
For better drought resistance of clover in the first phases of growth, soil fertility is of great importance : the higher it is, the faster the leaves form. Air-thermal pre-sowing seed treatment, early sowing with the introduction of granular phosphate fertilizers into the rows contribute to the rapid emergence of seedlings, enhance the development of the root system, which has a positive effect on the drought resistance of young plants.
In the second and subsequent years of plant life, the maximum need for moisture falls on the period of intensive accumulation of dry mass, which corresponds to the end of the stemming phase – the beginning of flowering. After mowing, the need for moisture increases, but to a lesser extent than during the formation of the first mowing.
When growing clover for seeds, the optimum soil moisture should be maintained until the flowering phase – 80% HB, during flowering – 60%, when seeds ripen – 40%.
To obtain a stable and good harvest of clover hay, the amount of precipitation should be at least 400-450 mm during the year.
Light requirements
Red clover refers to plants of long light. Northern clover is more sensitive to changes in day length. With a shortening of the day, the internodes in the late-ripening type of clover become shorter, the height of the stems decreases. With a long light day, the number of internodes decreases in it.
Clover is a relatively shade-tolerant plant, which makes it possible to oversow under the cover of other crops. Under low illumination (5000 lux), the photosynthetic activity of young clover leaves remains at an acceptable level (Department of Crop Production Moscow Agricultural Academy).
When red clover is oversown under the cover of high-yielding and relatively tall varieties of rye, wheat, oats , barley, root lodging of bread can be observed. In this case, especially unfavorable lighting conditions for grasses are created. For example, with continuous lodging of oats, the illumination decreases to 200-300 lux, with such illumination, photosynthesis does not occur in many herbs, respiratory processes begin to predominate over photosynthesis, which causes the consumption of reserve nutrients and the death of young plants (Department of Crop Production Moscow Agricultural Academy).
If by the time of strong shading, that is, lodging of the cover crop, red clover has formed 1-2 true leaves, then shading will lead to the death of 90% of the plants in 30 days; if the plants have formed 3-4 true leaves, then the death of plants will be 15% for the same period of shading (Department of Plant Industry, Moscow Agricultural Academy). Therefore, on high-yielding crops, agricultural techniques are used that ensure sufficient development of red clover by the time of possible lodging of the cover crop.
Soil requirements
Red clover prefers soddy-podzolic, gray forest, chernozem soils; when irrigated, it can also grow well on gray soils of Central Asia. Poorly tolerates acidic, highly saline, sandy loamy soils with sandy subsoil. When the pH of the soil solution is less than 4.5, it usually falls out. Optimal soil acidity 6-7.
Nutrition
Red clover is characterized by high consumption of potassium, phosphorus, calcium and other nutrients.
Since the availability of phosphorus in early spring is very low, the use of row phosphorus fertilizer is of great importance. With a sufficient supply of phosphorus, red clover takes root faster and forms leaves while increasing the number of nodules on the roots. When applying 50-100 kg/ha of granulated superphosphate at sowing, good rooting and development of plants can be achieved in 40 days.
In the second year of life, in the period from regrowth to the stemming phase, the content of nitrogen, phosphorus, potassium, calcium and magnesium in the aerial part of the clover increases by 5-10 times.
For the formation of 1 ton of clover hay from the soil, it is consumed: 5-6 kg of phosphorus, 16-17 kg of potassium, 15-17 kg of calcium, 5-5.5 kg of magnesium, 1.5 kg of sulfur.
Red clover belongs to potassium-loving plants. The effectiveness of potash fertilizers is significantly increased when lime is added. It is also responsive to the introduction of microfertilizers – molybdenum , boron , copper . Molybdenum contributes to the formation of nodules on the roots, better fixation of nitrogen from the air, increased foliage, plant productivity. Boron improves the formation of seeds, accelerates their ripening, and also contributes to the formation of nodules. Copper is involved in the formation of chlorophyll in the leaves, copper fertilizers are especially important on drained peatlands, where the content of this element is negligible.
Vegetation
In the first year, under favorable conditions, 4-5 days after sowing, the clover brings cotyledons to the soil surface, after 8-10 days it forms the first simple leaf. When sown under cover, clover usually develops poorly and does not bloom. By autumn, the plants form basal rosettes of leaves, developing on close internodes of stems, and lay the buds of future stems in the
axils of the leaves.
Starting from the 2nd year of life, it is customary to distinguish growth phases in meadow clover:
- root rosette;
- regrowth;
- shooting;
- budding;
- the beginning of flowering;
- full bloom;
- browning of the heads;
- full maturation of seeds.
From regrowth to the beginning of stemming, the aerial part of plants consists only of photosynthetic organs. During this period, the intake of plastic substances exceeds their consumption for the formation of new organs.
From the stemming phase to budding inclusive, there is an intensive growth of stems and an increase in the above-ground mass. At the same time, the root and outlet are depleted, consuming the accumulated reserves of nutrients.
In the period from budding to the beginning of flowering, the growth of the stems slows down somewhat. The leaf surface reaches its maximum development, the supply of nutrients exceeds the expenditure on the vital activity of the plant.
From the beginning of flowering to seed maturation, the consumption of nutrients for fertilization, seed formation and respiration exceeds the intake. During this period, the nodules can be emptied, and the nitrogen contained in them is spent on the formation of seeds.
Given these features of the biology of red clover, mowing at the end of the stemming phase, that is, when nutrient consumption exceeds their intake, will lead to very slow regrowth of plants and loss of yield. Also, mowing for hay in the full flowering phase leads to a large crop shortfall from the second cut due to slow regrowth. Red clover is mowed in the budding phase – the beginning of flowering. The duration of the flowering phase is 30 days.
Given that in the flowering phase and in the subsequent period, the plant consumes nitrogen from the nodules, the positive effect of nitrogen fertilizing of clover testes is obvious.
With a weak herbage, the cutting height should be higher in order to promote the faster growth of emaciated plants. On the contrary, in high-yielding fields with early stem lodging, mowing is carried out more often on a low cut.
The duration of vegetation of red clover depends on local climatic conditions. In the central regions of the Non-Chernozem zone, it usually takes 75 days from regrowth to the first cutting, from the first to the second cutting for hay – 45-65 days, from regrowth in spring to seed ripening – 125 days.
In the Central Chernozem zone, early-ripening clover from regrowth in spring to the first cutting takes 55-80 days, from the first to the second cutting for hay – 34-50 days, when harvested for seeds – 68-85 days.
In the Perm region, the duration from spring regrowth to the first cutting is on average 80 days, from spring regrowth to seed ripening – 120-130 days.
Clover reaches full development in the 2nd year of life, in the 3rd, as a rule, it becomes very thin, especially after harvesting for seeds. Usually, late-ripening clover in pure crops for fodder is used for 1.5-2 years, early-ripening – 1 year. For longer use, clover is grown in mixtures with cereal grasses.
Crop rotation
The place of red clover in a crop rotation depends on the cover crop. When overseeding under winter rye or winter wheat, it is placed in the field following the fallow. Clover is also sown under the cover of spring barley, oats, after potatoes or other crops.
In the north and east of the Non-Chernozem Zone, clover is usually sown under the cover of winter crops, going through clean or busy fallows, in the west, north-west of the Non-Chernozem Zone and in the Central Chernozem Zone – under spring cereals coming after tilled crops.
Clover can be sown under the cover of vetch-oat, pea-oat mixture for green fodder or hay, corn for green fodder, millet, Sudanese grass. Thus, various crops that provide good development of plants under cover can serve as precursors for red clover.
Clover is returned to its original place after 4-5 years, an earlier return is undesirable due to clover fatigue.
Fertilizer
Clover is responsive to the introduction of manure, peat-dung composts under a cover crop. Thus, the introduction of 36 t/ha of manure increased the collection of hay for 2 years of use by 3.4 t/ha (North-Western Research Institute of Agriculture, Leningrad Region). The introduction of 40 t/ha of manure increased the hay yield by 61.7% (Kursk Agricultural Experimental Station).
Manure affects the yield of hay also when it is applied under the previous crop. For example, the introduction of organic fertilizers for the previous crop (potato) increased the collection of hay by 33%, from 5.6 t/ha to 7.4 t/ha (Kirov Agricultural Institute).
Manure application rates, depending on soil fertility, soil and climatic conditions, are 20-40 t/ha.
Mineral fertilizers
The clover root system has the ability to absorb phosphorus from sparingly soluble compounds, so phosphorite flour can be used on acidic and slightly acidic soils of the Non-Chernozem Zone. So, with the introduction of 90 kg/ha P2O5 in the form of phosphorite flour increased the hay yield by 41.2% (Chernigov Agricultural Experimental Station). Similar results were obtained at the Smolensk and Orlov (former Shatilov) agricultural experimental stations.
High efficiency gives the joint application of phosphorus-potassium fertilizers – according to the generalized data, the increase is 33%. Recommended application rate for plowing or seedbed cultivation P45-60K30-60.
Row application of phosphorus fertilizers at the rate of 50 kg/ha of granulated superphosphate, or P10-15 , mixed with a hectare norm of seeds gives an increase in hay of 0.5-1.0 t/ha.
The application rates of mineral fertilizers for red clover depend on the results of an agrochemical analysis of the soil. The recommended rates are 250-300 kg/ha of superphosphate and 100-150 kg/ha of potassium salt. It is applied in the fall during the main tillage or in the spring during pre-sowing cultivation.
Red clover grows well on soils with a slightly acidic reaction, strongly reacts to liming , which sometimes doubles the yield from 4.2 t/ha to 8.5 t/ha in 2 years (All-Russian Institute of Fertilizers and Soil Science).
Moscow Agricultural Academy obtained the following data on the effect of liming on the yield of clover-timothy grass mixture for an average of 10 years:
- without fertilization, the increase from liming was 172%, from 1.3 t/ha to 3.4 t/ha;
- when applying mineral fertilizers – 58%, from 3.6 t/ha to 5.7 t/ha;
- when applying mineral fertilizers and manure – 47%, from 4.8 t/ha to 7.0 t/ha.
In addition, liming in combination with the application of organic and mineral fertilizers increases the winter hardiness and frost resistance of clover. For example, in the experiment when clover was frozen at the end of April at a temperature of -12 … -13 °C, 65% of plants were preserved on the limed soil, while 100% of the plants were preserved on the limed soil with the application of 40 t/ha of manure and phosphorus-potassium fertilizers (Moscow Agricultural Academy) .
Lime application rates are determined by the acidity of the soil, usually 3-10 t/ha.
In the Non-Chernozem zone, molybdenum microfertilizers give high efficiency. For example, in the Perm region, pre-sowing treatment of seeds in the amount of 50 g/ha of molybdenum increased the yield of hay from 7.4 t/ha to 9.0 t/ha.
According to All-Russian Institute of Fertilizers and Soil Science data, on soddy-podzolic loamy soils, the increase in hay yield from the application of molybdenum fertilizers to the soil or pre-sowing seed treatment was 40%, from foliar top dressing – 31%, the yield during pre-sowing treatment was 6.3 t/ha, when applied to the soil and foliar top dressing – 4.2 t/ha. On gray forest soil, seed treatment with molybdenum gave an increase of 38% from 3.4 t/ha to 4.7 t/ha.
For seed treatment, a 10% solution of ammonium molybdate is used, the consumption is 1 liter per hectare seeding rate. For foliar top dressing – 100-200 g / ha of ammonium molybdate, for ground spraying, the consumption of the working solution is 200-400 liters. Molybdenum not only increases the yield, but also increases the protein content by 1%.
Boron fertilizers are applied simultaneously with phosphate fertilizers at the rate of 2-3 kg/ha of boron, or phosphate fertilizers enriched with boron.
Top dressing
Autumn top dressing of red clover after cover crop harvesting is more effective (0.4-0.5 t/ha) than in the spring of the following year.
Top dressing is also carried out after the first mowing, subject to sufficient moisture. Plants of the second year of life are fed in the fall before leaving for the winter.
In the Trans-Urals, where the cold comes quickly enough, top dressing is carried out in the spring.
When top dressing, 150-200 kg/ha of superphosphate and 50-100 kg/ha of potash fertilizers are applied , or P 30-50 K 30-50 . After fertilization, the grass is harrowed in two tracks. After the second mowing, the same fertilizers are applied in the same quantities. With the autumn application of these fertilizers, the frost resistance and winter hardiness of clover increases.
If in the second or third year of use, cereal grasses begin to predominate in the herbage, in early spring only nitrogen fertilizers of 200-300 kg/ha are applied to top dressing with their incorporation by harrowing in two tracks. Nitrogen fertilizers are also applied after the first mowing to obtain a good harvest of hay or green mass from the second mowing.
As a spring top dressing, ash can be used at the rate of 0.5-0.6 t/ha.
Due to the slow development in the first year of life, meadow clover can easily be drowned out by weeds, therefore, clean fields are allocated for its crops, as well as other perennial grasses.
In the case of undersowing red clover under the cover of spring crops, deep plowing is carried out in autumn to a depth of 25-27 cm with preliminary peeling after harvesting the previous crop. Early harrowing and pre-sowing cultivation with simultaneous harrowing are important.
In the case of overseeding winter cover, special tillage is not required.
Soil preparation for sowing red clover should ensure good processing of the top layer and create a dense bed, thorough cleaning of the field from weeds, high breathability, a large supply of moisture and an adequate supply of nutrients.
Before sowing, it is advisable to carry out rolling with smooth or ringed rollers.
Pre-sowing seed treatment
Pre-sowing seed treatment includes cleaning from impurities and weed seeds, especially dodder, treatment with bacterial preparations and micronutrient fertilizers. Of the bacterial preparations, nitragin or rhizotorfin are used, which are preparations of pure cultures of nodule bacteria. Treatment with these preparations promotes the formation of nodules on the roots of clover and increases the yield of hay. When processing it is necessary to avoid hit of sunshine on seeds.
With a one-year use of clover, it is recommended to carry out scarification to increase the germination of seeds.
Sowing dates
When overseeding under the cover of winter crops, red clover is sown in early spring, before harrowing the cover crop, using disc seeders.
When oversowing under the cover of a spring crop, sowing is carried out simultaneously with a grain-fertilizer grass seeder СЗТ-3.6 in the inter-row spacing of the cover crop.
Delay in overseeding always leads to lower yields.
Seeding rate
Red clover can be sown in its pure form, mixed with cereals and/or other legumes. The seeding rate also depends on the area of cultivation, the composition of the grass mixture, and local conditions.
For soddy-podzolic soils, seeding rates of seeds of the 1st class are recommended:
- red clover mixed with meadow timothy – 12-15 kg/ha and 4-6 kg/ha, respectively;
- red clover in a mixture with horned bird ‘s eye and meadow timothy – 8-10 kg/ha, 6-7 kg/ha and 4-6 kg/ha, respectively.
For chernozems and limed soils:
- red clover in its pure form – 15-16 kg/ha;
- red clover in a mixture with meadow timothy – 13-15 kg/ha and 2-4 kg/ha, respectively;
- red clover mixed with alfalfa and timothy meadow – 7-9 kg/ha, 6-8 kg/ha and 2-4 kg/ha, respectively.
The seeding rate of late-ripening clover in its pure form is 14-16 kg/ha, early-ripening – 16-18 kg/ha. When sowing under cover, it is recommended to reduce the sowing rate of cover crop seeds by 20-30%.
Seeding depth
Red clover is a small-seeded crop, so the sowing depth is usually 1-2 cm, on light soils – up to 3 cm. Sowing depth should be controlled.
After sowing, the soil is rolled.
Crop care
To reduce the freezing of red clover, when harvesting the cover crop, a cutting height of 13-20 cm is set. High stubble allows better retention of snow, thereby preventing the death of plants from freezing. The following year, the stubble is removed using mowers, tractor rakes or harrowing.
In areas with insufficient snow cover and frosty winters, snow retention is carried out.
Fertilizing with mineral fertilizers must be included in the care of crops.
To combat weeds, spring mowing of early developing weeds, such as colza, and weeding are carried out. If quarantine weeds are found in the herbage, special measures are taken to exterminate them. So, to combat dodder, dinitroorthocresol (DNOC) is used in the amount of 35-50 kg/ha of the drug.
Diseases
Anthracnose is a clover disease that affects leaves, stems, heads, seeds, on which depressed brown-brown spots develop. In the future, individual organs dry up and break. Anthracnose can reduce the yield of hay by 50%, seeds – by 60%. To combat, the seeds are cleaned and dressed before sowing, mowing for hay is carried out earlier – in the budding phase, hay is immediately transported from the fields to the place of winter storage.
Ascochitosis affects mainly leaves, then stems and seeds. In this case, large spots of ocher-gray color are formed on the leaves. Ascochitosis leads to a deterioration in the quality of hay, reducing yields by 20%. For control, pre-sowing cleaning and dressing of seeds, early mowing of infected clover, pollination with sulfur in the amount of 30 kg/ha are carried out in the budding phase.
Clover cancer leads to the death of plants. The aerial part of the dead plants is easily separated from the root collar. For the fight, the correct alternation of crops is chosen, fertilizing is carried out with phosphorus-potassium fertilizers. Re-sowing clover in a field infected with clover cancer is possible no earlier than after 7 years.
Rust affects the leaves and stems of clover. Yield 80 days after infection is reduced by 80% in terms of dry matter. For the fight, sowing of varieties resistant to cancer is carried out, early mowing, phosphorus-potassium fertilizers are applied, dusting with sulfur is carried out, primarily in seed plots.
Pests
Nodule weevils in early spring eat the edges of the leaves, sometimes they can destroy the growing point. The larvae destroy the nodules on the roots and eat out depressions in them. For the fight, early feeding is carried out, which ensures the rapid growth of clover.
Clover weevils damage the leaves, buds and flowers of plants. One larva is able to destroy from 5 to 11 ovaries. Seed yield is reduced by 20-30%. To fight, clover is mowing in the budding phase and mowing the testicles.
Harvest
The best time for harvesting red clover for hay is mowing in the budding phase – the beginning of flowering. By this phase of the growing season, it forms the majority of the crop with high protein and low fiber, and the regrowth of mowed plants is the fastest, which ensures a high yield of green mass or hay from the second cut. Earlier mowing leads to a crop shortage, and young grass dries longer.
Green mass can also be used for making haylage, silage, grass meal, granules or briquettes. For mowing, a two-beam semi-mounted mower КДП-4.0 or КТП-6.0 is used, and at higher speeds – a mower КС-2.1. For mowing down and heavily tangled grasses, a rotary mower КРН-2.1 is used.
To obtain high quality hay, drying should be carried out as soon as possible. To do this, the grass in swaths is ted with the help of GVK-6.0 wheel-finger rakes or E-247 and E-249 rakes. Mower-conditioners KPV-3.0 can also be used. As the mass dries, it is raked into rolls, then collected in vehicles and transported to a place of permanent storage. Humidity of hay should be no more than 17%.
To reduce the loss of nutrients and vitamins, hay is dried by active ventilation. The dried mass is stacked or laid in a shed, a canopy and dried with atmospheric or heated air. Active hay ventilation units include a fan and an air distribution system. For one fan with a capacity of 25-30 thousand m 3 of air per hour, a stack is made 5.0-6.5 m wide, 5-6 m high and 10-12 m long. On the first day, ventilation of the stacked mass in the stack is carried out continuously, then – 1 hour every 6-8 hours.
The nutritional value of hay depends on the methods and conditions of its harvesting:
- with active ventilation, 100 kg of hay contains 60 feed units and 62.2% of digestible organic matter;
- for field drying 53 feed units and 60.1%, respectively;
100 kg of hay exposed to rain (slightly brown) contains 40 feed units and - 51.2% digestible organic matter;
- 100 kg of hay that has been rained twice (brown hay) – 24 feed units and 43.2%, respectively;
- 100 kg of hay that has been exposed to rain – 12 feed units and 34.2%, respectively.
Hay can be harvested with simultaneous pressing, for which a ПС-1.6 or ПРП-1.6 (roll) baler is used.
For the preparation of grass flour, the green mass is mowed with a КУФ-1.8 mower-chopper. The crushed mass enters the vehicles and is delivered to the place of drying. Dryers АВМ-0.4, СБ-1.5 and ЛКБ-ФЕ are used for drying. The dried mass is similar to flour, it is packed in bags made of thick fabric or paper. To cool the packaged herbal flour, it is left for 2-3 days, after which it is transported to a place of permanent storage. Store herbal flour in dark, cool, dry rooms.
Combines КСК-100, КСК-100П, E-281, КПКУ-75 are used for harvesting haylage. Mowed green mass after drying to a moisture content of 50-60% is removed from the field by pick-up choppers and transported to a storage place. The storage location must provide protection from air access, for which brick or concrete silos, concrete trenches are used.
The haylage is laid quickly (3-4 days) and very tightly so that during self-heating the temperature in the laid mass is not more than 37 °C. The filled storage is immediately covered. Hatches are closed in the silos, a plastic film is spread over the mass, the edges of which are sealed between the wall of the tower and the feed, for example, clay mixed with straw.
When laying haylage in a trench, it is recommended to put a layer of 30-50 cm of freshly cut grass on top of the dried mowed mass and then cover it with plastic wrap. The film is covered with a 10-15 cm layer of earth, on top of which is a 40-50 cm layer of straw.
When using haylage from towers, it is taken daily in layers of 20-25 cm or more. Haylage from trenches is also cut daily in vertical layers at least 30 cm thick. Haylage taken out of storage should be immediately fed to livestock.
For ensiling, clover is mowed in the budding phase. The mowing technique is similar to that used for making haylage. The green mass is well ensiled at a moisture content of approximately 65%. With excess moisture, 10-15% chopped straw is added. The mass is laid in towers or trenches and rammed. Loading trenches up to 2.5 m deep is carried out in 3 days, at a depth of 3.5 m and towers – in 5 days. A polyethylene film is laid on top of the compacted mass. In the trenches, a layer of earth 10-15 cm thick is also poured on top, on top of which is a layer of straw.
Growing red clover for seeds
The yield of clover seeds reaches 620 kg/ha (collective farm named after K. Marx, Chernukhinsky district, Poltava region, Ukraine, 1983). In the Braslav district of the Vitebsk region (collective farm “Vpered”, Belarus), the yield was 380 kg/ha of red clover seeds, in the Chusovsky district of the Perm region (collective farm “New Way”) – about 300 kg/ha.
Crop rotation
When growing red clover for seeds in specialized farms, special crop rotations are used. For the Non-Chernozem zone: 1 – uncovered sowing of perennial grasses; 2-4 – perennial grasses for seeds; 5-6 – tilled crops (fodder root crops, potatoes); 7 – cereals with undersowing of red clover; 8-9 – meadow clover for seeds. Such a 9- field crop rotation allows you to collect seeds of perennial grasses from five fields at once. In farms where the conditions are not favorable for growing seeds of cereal grasses, crop rotations are introduced for growing red clover seeds: 1 – cereals with red clover oversowing; 2-3 – meadow clover for seeds; 4 – row crops; 5 – row crops or grain crops.
Sowing and caring for crops
The maximum yield of clover reaches 250-450 stems per 1 m 2 of herbage , or 60-80 (rarely 100) plants per 1 m 2 at normal tillering (4-5 developed stems per 1 plant) . Therefore, clover of the second or third year of life is left for seeds, depending on the density of the herbage.
Seeds are sown in the usual ordinary or wide-row ways.
Seed crops are fed in autumn with phosphorus-potassium fertilizers to increase winter hardiness and frost resistance, as well as seed yield. Thus, autumn top dressing with phosphorus-potassium fertilizers gave an increase in the yield of red clover seeds in the experiments of the All-Russian Research Institute of Feeds 75 kg / ha, at the former Tatar Agricultural Experimental Station – 86 kg / ha. Spring top dressing with phosphorus-potassium fertilizers gives a slightly lower result. The rate of fertilization in top dressing is 200 kg/ha of superphosphate and 100 kg/ha of potassium salt.
In the stalking phase of clover, molybdenum microfertilizers are fed. To do this, spraying with a solution of ammonium molybdenum acid is carried out at the rate of 100-200 g of salt per 400 l of water to treat 1 ha. Such top dressing of seed plants increases the yield of seeds by 50-100 kg/ha and increases the weight of 1000 seeds.
In the conditions of the Non-Chernozem zone, fertilizing with boron micronutrient fertilizers, which are applied in the spring at a rate of 2 kg/ha of boron, gives a good effect. So, in the experiments of the Estonian Research Institute of Agriculture and Land Reclamation, the introduction of boron microfertilizers increased the seed yield by 61 kg/ha, in the experiments of the Latvian NIIZ – by 106 kg/ha.
Bees play an important role in increasing the yield of seeds. According to the recommendations of the All-Russian Research Institute of Beekeeping, for every 50 hectares of clover seed crops, 10-12 bee colonies must be taken out and trained by preparing an aromatic syrup, which is fed 100 g per bee colony. Aromatic syrup is prepared from 500 g of sugar per 0.5 l of boiling water. In the evening, clover flowers are immersed in chilled syrup and left to infuse overnight, and in the early morning they are placed in the feeders among the beehives.
Seed harvesting
Red clover seeds are harvested when 90-95% of the heads are browned using direct combining. For a more complete threshing of seeds from the heads, it is recommended to install an additional deck section on the SK-4 combine.
When harvesting a mixture of clover and timothy or a mixture of clover and fescue for seeds, two-tier mowing is used. First, timothy or fescue is harvested on a high cut, then after 2-3 weeks – clover with the second pass of the combine. Such harvesting reduces the loss of seeds of cereal grasses and increases yields.
Separate harvesting of seed plants begins when 60-70% of red clover heads turn brown. The herbage is mowed into rolls, and after the mass has dried, it is threshed with combines. This method is effective in dry and warm weather.
There is also a method in which the threshing of the mowed mass of family clover is carried out in a hospital. This method eliminates the loss of seeds from the combine.
The most effective method of harvesting testes is determined based on weather conditions and technical feasibility.
The two-cut type of red clover, when planted very early in its pure form, is capable of producing seeds in the first year of life, the single-cut type can produce seeds only in the second or third year of life.
Clover of the second year of life (1st year of use) is best suited for obtaining seeds, while according to the data:
- All-Russian Research Institute of Fodder, the yield of clover seeds in the 1st year of use was 530 kg/ha, in the 2nd year of use – 170 kg/ha;
- North-Western Scientific Research Institute of Agriculture, the yield of clover seeds of the 1st year of use is 280 kg/ha, the 2nd year is 130 kg/ha;
- Jõgeva breeding station – 290 kg/ha and 170 kg/ha.
In conditions of optimal moisture supply, it is recommended to obtain seeds from the second cut. In this case, the plants are less damaged by pests, and the first cutting is carried out in the budding phase.
In the southern areas of clover sowing, seeds are usually obtained from the second mowing.
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.