Sugar beet is a technical (row crop), a sugar-bearing crop that serves as a raw material for sugar production.
The agro-technology of sugar beet cultivation is given in the article: Cultivation of sugar beet.
- Economic importance
- Agrotechnical importance
- History of the crop
- Area of cultivation
- Botanical description
- Biological features
- Nutrition of sugar beets
- Cultivation of sugar beet
Sugar beet is cultivated mainly for sugar production and also used for fodder purposes.
In the USSR it was planned to increase sugar beet production to 92-95 million tons by 1990 by increasing yields, improving quality and reducing losses.
World sugar production by the end of XX century amounted to 135 million tons, 30% of which accounted for sugar produced from sugar beets.
The sugar content (sucrose) in carrots of modern varieties on average reaches 16-20% and ensure the yield of sugar up to 10 tons per 1 ha. Usually from 1 ton of roots get 130-160 kg of sugar, as well as 800-830 kg of fresh pulp, 35-40 kg of molasses.
In terms of fodder value, sugar beet surpasses fodder beet. 100 kg of roots correspond to 26 fodder units and contain 1.2 kg of digestible protein, 0.5 kg of calcium and 0.5 kg of phosphorus. A yield of 30 t/ha of roots and respectively 15 t/ha of leaves corresponds to 10500 feed units. On average, the ratio of the mass of roots and tops varies from 35 to 50%.
The chemical composition of leaves: dry matter – 27%, protein – 2.5-3.5%, fat – 0.8%, vitamins.
Fodder value are also waste products – pulp, molasses. The total feed value of by-products from processing 25-30 t/ha of roots and 10-15 t/ha of sugar beet leaves is about 5000 feed units.
In terms of fodder value sugar beet leaves are equal to green mass of seeded grasses. 5 kg of leaves corresponds to 0.9-1 fodder unit with a protein content of 110 g. With a yield of 25-30 t/ha, the leaves give approximately 2,000 fodder units. However, sugar beet tops contain oxalic acid salts, so feeding it to animals in large quantities in fresh or ensilaged form can lead to disruption of calcium metabolism and digestive disorders.
Desugared beet chips, or pulp, contains 6-7% dry matter. Pressed pulp is also produced with a solids content of 10-12%, pressed – 13-15% and dry – 86-88%. 100 kg fresh pulp corresponds to 8 feed units and contains 0.3-0.9 kg of digestible protein, 100 kg of dry pulp – 80-85 feed units and 3.6-3.9 kg of digestible protein, 100 kg of acid pulp – 9.7 feed units and 0.6 kg of digestible protein. It is a good feed for cattle. The yield of pulp yield at 30 t/ha is 24 t/ha.
Molasses is used in the confectionery and food industries. Fodder molasses contains up to 60% of sugars, 9% of minerals; its fodder value is close to that of grain: 100 kg contain 77 fodder units and 4.5 kg of digestible protein. Molasses is used to produce glycerin and alcohol.
Sugar beet has an advantage in fodder value in relation to a number of crops. For example, the yield of green mass of corn on the cob is 30 t/ha or 7000 fodder units/ha, while sugar beet – 30 t/ha roots and 15 t/ha tops or 10500 fodder units/ha.
A waste product of sugar beet production is defecation mud (defecate), which serves as an industrial organic fertilizer. Chemical composition: 40-50% calcium carbonate (lime), 15% of organic matter, 0.2-1.7% of nitrogen, 0.2-0.9% P2O5, 0.5-0.9% K2O.
Due to the fact that sugar beet requires deep tillage, fertilization and good crop care, it serves as a valuable predecessor for many crops in the crop rotation, increases the productivity of field crop rotations, fields after it remain clean of weeds, and a sufficient supply of moisture remains in the soil. According to the All-Russian Research Institute of Sugar Beet and Sugar named after A.L. Mazlumov, or former Ramon experimental station, the yield of crops sown after sugar beet is on average 8-19% higher than those sown after winter crops.
Table. Effect of sugar beet and winter crops on the yield of subsequent crops in the crop rotation (All-Russian Research Institute of Sugar Beet and Sugar)
|Veatch-oat mix (for grain)|
|Sudan grass (for hay)|
After the harvesting of sugar beets in the field a large amount of crop residues remain, which serve as organic fertilizer or for fodder purposes in fresh, silage or dried form.
The introduction into crop rotation of such roots as beets is inextricably linked with the transition to a more perfect system of field farming, with the improvement of land tillage and cattle fodder, etc.
V.I. Lenin. The Development of Capitalism in Russia. Collected Works, Vol. 3.
History of the crop
The sugar beet was introduced to culture relatively recently.
The cultivated biennial beet is descended from the wild annual beet, which began to be cultivated in Western Asia 2000-1500 years B.C. Wild beets are now found on the shores of the Mediterranean, Caspian and Black Seas, in Transcaucasia and Asia Minor. Wild beets are distinguished by their coarse, woody roots and low sugar content.
The first to enter into culture were leafy forms – Swiss chard, then in the XVIII century. Sugar beet is descended from the white vegetable form, or Silesian, which arose from the selection of natural hybrids of low-sugar leaf and fodder beet.
Crystal sugar, or sucrose, was isolated from beets in 1747 by Markgraf. It was proved that beet sugar and cane sugar are one and the same substance. However, obtaining sugar from beets was proved only in 1799 by Ahard.
In Russia, sugar beet and sugar production originated in 1802, when the first sugar factory was opened in the village of Alyabyevo in the former Tula province. However, it was not until the middle of the 19th century that sugar production from sugar beets started on an industrial scale.
For a long time the sugar content in cultivated beets remained low. At the beginning of the XIX century sugar content of root crops was 6.7%, by 1860 it was raised to 10%. Currently, the best varieties have a sugar content of over 20%, while also increasing the mass of root crops.
Area of cultivation
The major sugar beet producing countries are Russia, Ukraine, France, the United States, Poland, Germany, Italy, Romania, Spain, the Czech Republic, the United Kingdom, Belgium, Hungary and Turkey. 70-80% of all areas sown and gross yield of sugar beet fall on the countries of Europe.
In 1981 the area of sugar beet cultivation in the world was 9,345 thousand hectares, including 3,633 thousand hectares in the USSR, or 38.9%. In the USSR itself 1800 thousand hectares (49.1%) were in Ukraine and 1600 thousand hectares (42.9%) in the RSFSR (now Russia), the share of other republics was about 8%. During the Great Patriotic War and in the postwar period, sugar beet spread to Moldova, Belarus, Latvia, Lithuania, Kazakhstan, Kyrgyzstan, Georgia and Armenia.
In Russia, the main beet-growing regions are the Central Black Earth Zone and Krasnodar Territory. Sugar beet is also grown in the Altai and Stavropol regions, the Samara and Saratov regions, the south of the Non-Chernozem zone, Western Siberia and the Far East. The crops continue to move north (to 60°N), east and south (40°N) of the country, moving beyond the traditional beet-growing areas. Of importance is the spread of crops in the irrigated lands of the Volga region and the North Caucasus.
In Russia the area under crops at the end of the 20th century shrank to 0.8-1 million hectares, i.e., over the period of the 1990s the area under crops decreased by half. The gross yield decreased by 1.5-2 times to 18 million tons with an average yield of 23 tons/ha.
Sugar beet is one of the high-yielding crops and takes one of the first places among field crops by yield per unit area.
In 1984, the yield of sugar beet (factory beet) in the USSR was 24.6 t/ha. In 1982, the average yield on variety plots was 38.6 t/ha; on the irrigated lands of the state variety plots of Ukraine – 77.7 t/ha.
In Soviet times, high yields of sugar beet were harvested:
- in 1982 in Ust-Labinsk district of Krasnodar Krai (collective farm “Kuban”) was harvested 45.0 t/ha from an area of 2200 ha;
- on the average for 1976-1980 in Ukraine – 30.0 t/ha from the area of 1796 thousand hectares;
- in 1983 in Zhashkovsky district of Cherkasy region (Ukraine) on the industrial technology yielded 46.6 t/ha from an area of 11400 ha;
- in 1983 in Myroniv district of Kyiv region (Ukraine) – 41.0 t/ha from an area of 8400 hectares.
Labor costs were 118-140 man-hours/ha. The achievements of the USSR in beet farming (as well as in agriculture), as well as the importance given by the state to farming, show respect for the master beetroot growers who received the titles of Heroes of Socialist Labor: E.N. Parubka (Suvorov collective farm, Zhashkovsky district, Cherkasy region, Ukraine), I.M. Nagorny (Chapaev collective farm, Kochubeyevsky district, Stavropol region), S.L. Bryntsev (Lgovskaya experimental selection station, Kursk region), M.I. Klepikov (Kuban collective farm, Ust-Labinsky district, Krasnodar region) and others. The achievements of these agrarians are the annual sugar beet yields of 40-50 t/ha with minimal labor inputs. Many of them were awarded the title of USSR State Prize winner for their achievements in beet farming.
At present, in Krasnodar Krai, Voronezh and Belgorod Oblasts, yields of 50-60 t/ha, and in irrigation conditions – 70-80 t/ha. Promising directions to increase the sugar beet yield are seed breeding, new cultivation technologies, specialization of enterprises.
Increasing the sugar beet yield is important if sugar yield per unit area is increased. The sugar yield at Russian sugar factories is 10.2-12.5%, while in European countries this indicator reaches 16.2-17.5% (in Switzerland it is 19.0%). Thus, the sugar yield per unit area in Russia is 1.5-2.0 t/ha, while in European countries it is 8-12 t/ha.
Current achievements in obtaining maximum yields:
- Switzerland – 68 t/ha;
- Austria – 67 t/ha;
- France – 61 t/ha;
- Spain – 56 t/ha;
- Belgium – 55 t/ha;
- United Kingdom – 55 t/ha;
- Germany – 54 t/ha;
- Netherlands – 51 t/ha;
- Denmark – 50 t/ha.
Sugar beet (Beta vulgaris L., v. saccharifera) belongs, as well as forage beet (v. crassa), leaf beet (v. cicla) and table beet (v. esculenta), to the family Marecae (Chenopodiaceae).
Sugar beet, like other root crops, belongs to geophytes. Geophytes are characterized by the fact that their epicotyl (head), hypocotyl (neck) and proper root in the course of evolution turned into organs of storage of stored nutrients, and Renewal buds, from which leaf and flower-bearing shoots appear, are established in above-ground or underground organs close to the soil surface.
The root system of an adult sugar beet plant includes a thickened main root and a dense network of thin ramifications departing from the main root. It penetrates into the soil up to 2.5 m deep and spreads out in width within a radius of 40-50 cm. Root mass averages 400-800 g.
The main root, or root-fruit (hereinafter referred to as root), has a cone-shaped elongated shape, slightly compressed from the sides, usually not branching. The root is subdivided into:
- head of the root, or shortened stem, which develops completely above the soil surface and bears leaves; it has the lowest sugar content;
- the neck, or hypocotyl, or sub-cotyledonous knee, which is the part of the root crop without leaves and lateral roots, it accumulates the greatest amount of sugar, up to 19-20%;
- root itself, the lower part of the root-fruit, or tail, usually has a conical shape, on which the lateral roots are formed, arranged in two longitudinal rows, accounting for 70-85% of the length of the root crop.
When a cross-section of a root of an adult plant, the central vascular-fiber bundle (“star”) and alternating concentric layers (rings) of conducting bundles, which communicate with the conductive tissue of the leaves, can be seen. Each of these conductive bundles consists of the xylem, which is the large woody cells that transport water and dissolved nutrients from soil to leaves, and the phloem (bast), which is the thin-walled cells that transport sugars and other photosynthetic products in the opposite direction from the leaves to the roots. Between the rings of conducting vessels are parenchyma cells, in which sugars are deposited.
Anatomically, species of the genus Beta have a primary, secondary and tertiary root structure. In the primary structure, primary xylem and phloem vessels are located in the center of the root, separated from each other by cells of the main tissue – parenchyma. Together they constitute the central conductive cylinder of the root. Around the conductive cylinder there is pericambium (pericycle) – educational tissue consisting of one layer of parenchyma cells. Thus, the pericambium separates the cells of the primary root from the central conductive cylinder.
After the plant develops its first true leaves, secondary changes begin to occur in the root. Two cambial arcs are formed in the parenchymal cells of the central cylinder, which curve parallel to the primary phloem, reach the pericycle and then take the form of a circle. Cells arising from the cambial ring toward the center form secondary xylem (wood), toward the periphery of the root – secondary phloem (bast). Pericycle cells form the secondary cortex, which consists of a thin layer of cork tissue. The formation of secondary cortex and cork tissue leads to the shedding of the primary cortex, called root molting. After molting, the roots thicken, for this reason, the formation of plant density, i.e. thinning, is carried out in a short time, and the more sprouts per meter of seed row, the earlier thinning begins, to reduce the influence of intraspecific competition.
After root molting, tertiary changes begin in the secondary cortex. A second cambial ring is formed in the parenchyma of the secondary cortex. After xylem elements are deposited inwards and phloem elements – outwards in the form of bundles with parenchyma cells between them, the second cambial ring ceases its activity. It is replaced by the third cambial ring, which is formed as a result of division of the next generations of the same educational cells that gave rise to the first ring, at some distance outside. The fourth, fifth, etc. rings are formed according to the same scheme. In modern varieties, the number of cambial rings reaches 12.
Thus, the thickening of the root crop occurs as a result of the formation of new rings and the growth of inter-ring parenchyma. In varieties with high sugar content, the number of rings is usually higher than in yielding ones, and the inter-ring parenchyma is narrower, the root are smaller.
In the root, the vascular bundles that were formed first are located in the center, while the youngest ones are located on the periphery. In the leaf rosette, on the contrary, the older leaves are outer and the younger ones are inner. In this regard, the vascular bundles are crossed in the head of the root crop, which leads to an increase in the relative fiber content.
A mature beetroot contains 75 percent water and 25 percent of dry matter, of which 17.5 percent is sugar, 7.5 percent – fiber, 2.4-2.5 percent – pectin substances, 0.1 percent – proteins and ashy substances, 0.8 percent – fructose, glucose and other carbohydrates (except sucrose), 1.8 percent – nitrogenous substances. All substances that are not sucrose (sugar itself) in the composition of dry matter in beet farming are called “non-sugars”. Their content depends on varietal characteristics, soil and climatic conditions and agricultural technology. In sugar production, pectin substances are considered undesirable, as they get into the juice during the processing of sugar beet, making it difficult to filter and crystallize the sugar.
The sugar in the roots is distributed unevenly. Vertically, its content increases starting from the head, reaches a maximum in the widest part of the root, and then begins to decline further down. Horizontally, the content increases from the center to its middle layers, then to the bark of the root decreases.
In sugar production, the content of soluble “non-sugars” – invert sugar, i.e. fructose and glucose, and soluble nitrogenous compounds (betaine and other amino acids), which prevent normal crystallization of sugar, is important. Therefore, the quality indicators of sugar beet as raw material for sugar production, in addition to sugar content, is the quality of juice (percentage of sugar in dissolved solids), and the content of invert sugar and “harmful” (non-protein) nitrogen. The soluble ash content of sugar beet is also an indicator of quality, as one part of this ash converts five parts of sugar into molasses.
The quality of the diffusion juice is calculated by the formula:
The quality of juice in production varies from 80 to 90%. To estimate the probable yield of sugar, we use the index of technical grade of juice, calculated by the formula:
In 1957 Drahovska and Sander (Czechoslovakia) proposed an indicator of technological properties of sugar beet – MB-factor. It is defined as the amount of molasses that is obtained per 100 parts of sugar produced from this raw material. The index is calculated on the basis of the sugar content of the beet and the soluble ash. The soluble ash is determined by the conductometric method proposed by Sommer in 1958.
The leaves of sugar beet are large, entire, petiolate. The shape changes with age: young leaves have short petioles and rounded laminae, older leaves have elongated petioles and a heart-shaped lamina. The leaf blade surface is smooth or crimped or wavy, depending on the cultivar and growing conditions.
Depending on the location of the leaf blade, there are flat, tapering leaves that almost lie on the ground, and protruding ones that point upward. The latter are characteristic of yielding varieties. Plants with a standing rosette are less likely to be damaged by mechanical crop care.
A single leaf can be up to 50-70 cm long. Leaves account for 30-50% of the mass of the yield.
The flowers of sugar beet are of the pentate type, are ovipotent, have a greenish perianth and a three-lobed stigma. They are arranged in the axils of leaves along the stem and its lateral branches in groups of 2-6 in whorls, which form an inflorescence – a loose spike (whorl cluster).
The flowers of the one-growing beet are arranged one by one. Flowering lasts 20 to 40 days. The nectar has a honey odor.
Beets are strict cross-pollinators, pollinated mainly by wind, partly by insects. Pollen can spread to a distance of 4-5 km. Therefore, given this property, as well as the lack of a barrier of non-cross pollination between sugar beet, fodder beet and table beet, it is necessary to maintain spatial isolation between crops to obtain seeds.
The fruit of sugar beets is a nut and has a thick two-layer pericarp of loose, woody tissue. The fruit forms a globule, or copulpus of beets (often referred to as seeds), consisting of 2-6 fruits. The size of the globules depends on the number of fruits. When the fruit ripens, the sepals become woody and fuse with the hard shell. The top of the mature fruit has a relatively flat or weakly convex cap, under which there is a horizontally lying seed. Single-growing globules have one nut.
The weight of a 1000 globules varies from 15 to 50 g, the single-seeded globules 20 g. The seed accounts for 25-30% of the weight of the globule.
The advantage of single-seeded beets is that they reduce labour costs for seedling thinning, making it possible to mechanize the whole process of caring for the crops.
The seed is covered with a brown, glossy seed coat. The embryo is coiled almost in a ring around the perisperm, where the nutrients are stored. The embryo consists of two cotyledons, with a bud between them, a sub-cotyledonous knee, and a germinal root. For sowing, angular-shaped and grayish-yellow globules are suitable.
Sugar beet is characterized by its ability to use lower temperatures in the spring and autumn periods. It is relatively resistant to frosts.
Seeds begin to germinate at 2-5 °C, viable seedlings appear at 6-7 °C. But germination at this temperature is slow, seedlings appear in 18-20 days. Higher temperatures reduce the period from sowing to emerging: at 10-12 °C it is 12-14 days, at 15-17 °C – 7-8 days. Uniform and strong sprouts are an important condition for high sugar beet yields.
Sprouts can withstand spring frosts down to -4 … -5 °C. Frosts of -3…-4 °С are dangerous during fork phase. After the appearance of the first couple of true leaves, i.e. 6-8 days after sprouting, sugar beet can survive frosts down to -6 … -8 °С.
According to the All-Russian Research Institute of Beetroot Physiology Laboratory, the probability of transition to flowering increases as the crops move north, due to lower temperatures, lengthening of daylight hours and saturation of light with long-wave rays.
According to the results of the experience of the All-Russian Research Institute of Beetroot, conducted on the cultivation of sugar beet in a greenhouse at different temperatures, higher temperatures reduce the probability of transition to flowering. All plants that were in the warm chamber did not follow the path of reproductive development. Increased temperatures inhibit the processes of vernalization, prolong their terms and stop reproductive development.
Table. Influence of temperature on the development of sugar beet (All-Russian Research Institute of Beet)
Optimal temperatures for photosynthesis and growth of sugar beet are 20-23 °C, but growth and sugar accumulation continue up to 6 °C in the fall. The sum of active temperatures in the first year of vegetation, in the main beet-growing areas is 2200-2400 °C, in the north of the Non-Black Earth zone and in Siberia – 1800-2000 °C, in the southern regions – up to 3000 °C.
Hot weather strongly affects the water balance of plants, resulting in depression of photosynthesis and increased respiration, accompanied by consumption of sugars and stunted growth.
Sugar beets have high moisture requirements from the first signs of life, but are drought-resistant. Seeds, which are enclosed in a woody pericarp shell, need 120-170% water of their globules weight and access to air for swelling and germination.
Transpiration coefficient of sugar beet depends on nutritional, thermal, light conditions and other factors. Varies in different phases of the growing season from 240 to 400. Sugar beet sparingly consumes moisture, but the total water consumption of 1 hectare of crops is quite high due to the formation of large amounts of dry organic matter. It is considered that to grow 100 kg of roots and the corresponding number of leaves at an average yield of 40-50 t/ha, consumes about 8 m3 of water (water consumption factor), in terms of 1 hectare water consumption will be 3000-4000 m3. These data indicate the great importance of methods aimed at accumulation and conservation of water in the soil, and explain the high responsiveness of sugar beet to irrigation.
The maximum water consumption of sugar beet is observed during the period of intensive growth, i.e. in July-August. Optimal conditions for growth and formation of high yields are soil moisture of at least 60-80% of the smallest moisture capacity.
Transpiration coefficient of planting (beets planted in the second year) averages 725, which is significantly higher than that of beets of the first year of vegetation. The total water requirement per plant planted for seed at 60% soil moisture varies from 30 to 75 L, or about 0.7-1.2 L/g of air-dry seed, depending on conditions and development of the seedlings.
The water requirements of seedlings and beets of the first growing season are different during the growing season. Planting-beet plants show intensive transpiration much earlier than first-year beets, reaching its maximum usually in late June-early July (a month earlier than in factory beets), when flower stalks are thrown out and before the end of flowering. This period is when the beet plantings blossom. The optimum moisture content for normal development of plantings is equal to 60-70% of the smallest moisture content.
The decrease in beet yield in years of insufficient moisture is somewhat less than in other crops, which is due to the powerful, deeply penetrating root system that begins to develop intensively in the first phases of growth and allows plants to use subsoil water reserves from a depth of 2 m. Sugar beet also has a long growing season and the ability to use late summer precipitation.
The following meteorological factors determine maximum sugar beet yields:
- with an average spring onset, May, as the first month of the growing season, may not be wet;
- August should not be dry, but with good insolation and sufficient rainfall;
- heavy rains in September have a negative effect on the quality of the crop;
- warm September and especially October cause high sugar content of roots.
Sugar beet is a long-day plant with high light requirements. Plant development and sugar accumulation strongly depend on the duration and intensity of sunlight.
Lack of light leads to a sharp decrease in yield and sugar content of roots. Lack of light can be due to the influence of weeds.
During the sugar accumulation period sugar beet is the most demanding to light. 1 dm2 of leaf surface in normal light accumulates about 12 mg of sugar per hour. Short changes of cloudy and sunny periods do not affect the growth of roots and sugar content.
Sugar content depends on the number of sunny days during the second half of the growing season, i.e. August and September, and an adequate supply of moisture.
Soils optimal for sugar beet production are structural black earth soils with high organic matter content, chestnut, gray and dark gray forest soils, as well as lowland, flood plain and humus-rich meadow-marsh soils. Loamy soils are optimal by mechanical composition. In the Non-Black Soil Zone, it yields high yields provided a high level of farming techniques, liming, and a deep humus horizon.
It grows badly on poor sandy and very heavy clay soils, on heavy soils the roots begin to branch.
Neutral or weakly acidic reactions of soil solution (pH 6,5-7,5) are preferable for sugar beet. Sugar beet suffers from increased acidity pH <6. Beets are salt tolerant and are capable of producing high yields with good sugar content in root crops on saline soils. To obtain the same results on highly saline soils, flushing irrigation and application of organic fertilizers are necessary.
Most scientists consider the optimum density of compaction of the arable layer of soil 1.0-1.2 g/cm3 (1.0-1.3 g/cm3).
Sugar beet is also demanding to the conditions of soil aeration, especially during the period of seed germination and root formation.
The normal level of groundwater occurrence is considered to be 1.5-2 m from the soil surface.
Nutrition of sugar beets
Sugar beet requires a large amount of nutrients to form a crop. According to experimental stations, with a yield of 30-40 t/ha of root crops and 15-20 t/ha of leaves, 120-140 kg/ha of nitrogen is absorbed from the soil (according to other data 180-240V.V. Kolomeychenko. Crop production/textbook. – Moscow: Agrobiznesentr, 2007. – 600 с. ISBN 978-5-902792-11-6. Page. 382), 40-55 kg/ha of phosphorus (according to other data 60-80V.V. Kolomeychenko. Crop production/textbook. – Moscow: Agrobiznescenter, 2007. – 600 с. ISBN 978-5-902792-11-6. Page. 382), 150-200 kg/ha of potassium (according to other data 210-280V.V. Kolomeychenko. Crop production/textbook. – Moscow: Agrobiznescenter, 2007. – 600 с. ISBN 978-5-902792-11-6. Page. 382). For example, the content of nutrients in the yield of 103.6 t/ha of root crops and 33.2 t/ha of leaves, was 477 kg of nitrogen, 114 kg – P2O5, 498 kg K2O (H. Baidich, Vinnitsa region, Ukraine). On average, 5-6 kg N, 1.5-2 kg P2O5 and 6-7.5 kg K2O are needed to form one ton of root crops and the corresponding number of leaves.
The application of a full dose of mineral fertilizers for sugar beet in the main application or fractionally is equal in effectiveness.
Sugar beet is also demanding of calcium and trace elements, especially boron and manganese.
Good nitrogen nutrition promotes leaf and root growth. Nitrogen deficiency is manifested by a light green color of the above-ground part of the plant, early yellowing and die-off of old leaves. With a lack of nitrogen, the veins of vascular bundles and adjacent tissue turn yellow first, but the parts of the leaf away from the veins may retain a light green color. An unbalanced excess of nitrogen leads to a decrease in sugar content and white sugar yield.
Phosphorus deficiency results in stunted growth, decreased root mass, and sugar accumulation in the leaves. In this case, the young leaves and root crop provide their need for phosphorus by its reutilization from the old leaves. Reutilization occurs even if plants are sufficiently supplied with phosphorus, but less actively.
With a deficit of phosphorus from the beginning of the growing season, the seedlings strongly lag behind in growth, getting a dull dark green color. With severe phosphorus deficiency, dark brown spots appear on the leaves, the edges of the lower leaves become dark brown and die off.
As a rule, soils in the main beet-growing areas of Russia are low in phosphorus.
Potassium promotes plant resistance to drought and frost.
Lack of potassium is manifested by drying of the edge of the leaf plate, starting with the most productive middle leaves. Potassium deficiency leads to a sharp decrease in the sugar content of roots.
Calcium deficiency leads to weakening and stunted growth of plants and, above all, the root system. At the same time on the leaves appears characteristic chlorosis: leaves become mottled color, areas between the veins pale, while the veins themselves remain green.
Sulfur deficiency appears in sugar beet leaves in the form of brown spots and yellowing.
Iron deficiency in the soil is manifested by chlorosis of the leaves and their yellowing.
Manganese is involved in the accumulation and movement of sugars from the leaves to the root and stimulates the growth of new tissues at the growth points. It is also involved in the absorption of iron from the soil and prevents leaf chlorosis.
Lack of boron leads to a disease of sugar beet called heart rot, or dry rot. This disease causes the growth point and rudiments of the youngest leaves to die off. The young leaves curl, their petioles and veins turn brown or black, then they wilt and die. Withering and dying develops from the inside of the rosette to the outside. The outer leaves turn yellow or are covered with rust-like spots, wither, and die off. Subsequently, the root tissue is destroyed – first near the neck, then deeper. The decayed tissue becomes dry and crumbly. Beets consume a large amount of boron during the period of 13-14 weeks after sowing, during other periods the need for boron is low.
Sugar beets absorb nutrients throughout the growing season, but nutrient requirements vary during the individual growing seasons.
During the initial period of growth and development, sugar beets need the most nitrogen and phosphorus. By the middle of the growing season, the intake of all nutrients reaches its maximum. During the second half of the growing season, sugar beet plants absorb more than 25% of all nitrogen and about 40% of potassium. The need for phosphorus remains the same as in the middle of the growing season.
Table. Nutrient inputs to sugar beet plants during vegetation, % of total inputs (P.V. Karpenko)
Sugar beet is a biennial plant (like all root crops). In the first year of life, a rosette of leaves, of which there are 50 to 90, and a root crop with a supply of nutrients are formed. In the second year the planted roots produce from axillary buds leaves and branching ribbed flower-bearing shoots 120-150 cm high.
The duration of vegetation in the first year is 150-170 days (in Siberia – 100-130 days), in the second year – 100-130 days. Due to the reserves of nutrients, the development of plants in the second year of life is faster, which is also associated with greater demands on water and nutrient regimes.
It is customary to distinguish phases of development of sugar beet in the first year:
- sprouting, or fork phase – emergence of cotyledons to the soil surface and their greening;
- 1-5 pairs of true leaves, the first pair of true leaves formed 8-10 days after germination;
- leaf closure;
- leaf opening.
Tendency to flower
In the first year of sugar beet life, dormant buds are laid in the leaf axils. Most of them are established at high temperature. Its further decrease to 0-8 °C leads to their development. Under natural conditions, this decrease should occur in winter, and then in the spring of the second year, these buds produce flowering shoots. However, this process can also be observed in the first year of plant life, resulting in the phenomenon of sugar beet flowering.
If a flower-bearing shoot is formed in the first year of vegetation, flowering roots are obtained. The tendency to flowering usually occurs with a short period of vernalization with very early sowing, a cold and long spring, and a long daylight period. Flowering leads to a reduction in the sugar content of root crops, partial hardening of tissues, and a reduction in root mass. Processing of such roots is more difficult, and canker rot develops during storage. Early flowering is especially undesirable.
The main way to prevent flowering is to sow in time and use resistant varieties.
If beets are grown for seed in the second year, the opposite phenomenon is possible, in which plants do not bloom and do not give seeds. Such plants are called “stubborn”. The reasons for this phenomenon is considered physiological unpreparedness of root crops for further development. Caused by the action of high temperatures, early harvesting, autumn and spring drying of mother root crops, high storage temperature, shallow planting.
When a sugar beet seed germinates, the spine and subcotyledon are the first to grow. They tear through the seed coat and come out. The cotyledons remain inside the fruit for some time, through which the nutrients stored in the seed continue to nourish the young sprout. The cotyledons then emerge onto the soil surface, quickly turning green, beginning to provide the plant with photosynthetic products, which is especially important during the initial growth period. Any damage to the cotyledons will cause significant damage to the future crop. After the formation of 6 to 8 true leaves, the cotyledons quickly wither away.
The cotyledon or “fork” phase lasts 6-8 days. Then the true leaves emerge from the central bud.
Each new leaf appears every 2-3 days in early summer, 1-2 days in midsummer. During the growing season, the plant may produce up to 60-90 leaves. The total area of the leaf surface reaches 3000-5000 cm2, which is 3-5 times greater than the area of the soil occupied by the plant itself. The rate of leaf growth and leaf power depend on the availability of water and nutrients, primarily nitrogen.
Depending on the development of the plant, the emerging leaves differ in size, shape, and longevity. The most productive leaves are those of the middle tiers, which appear in summer, from the 10th to the 25th. They develop quickly, surviving for up to 60-70 days. The lifespan of the first leaves is 20-25 days. Active photosynthetic activity of the leaf is about 25 days.
In the first half of summer, the growth of leaves is more rapid than their die-off, so the weight of the haulm increases. Leaf development is greatest in the second half of July and August, and then leaf mass begins to decrease rapidly. By the time the crop is harvested, the proportion of leaves is 30-60% of the weight of the root crop.
The optimal leaf surface area of sugar beets is 40-50 thousand m2/ha.
Leaf death occurs faster with a lack of moisture.
Root and root system development
During the first days of plant development, the primary root develops slowly. But in the fork phase, it reaches a length of 15-20 cm and begins to grow in the plane of the cotyledons by lateral branches with a dense network of root hairs.
With the appearance of the first true leaves begin to thicken hypocotyl and main root, reaching a length of 30 cm. In this regard, thinning in dense crops should be completed by the beginning of root formation.
The development of the root and root system is linked to the formation of leaves: the earlier and more leaves are formed, the faster the growth of the main root.
Table. Development process of sugar beet (Uladovo-Lulinets experimental selection station All-Union Research Institute of Beet, Ukraine)
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