Winter wheat is a cereal crop belonging to the botanical genus Triticum of the cereal family (Gramineae). According to the method of cultivation it belongs to the winter cereals of group I.
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Economic importance
Winter wheat is the most valuable and productive cereal crop. Its grain contains a large amount of gluten proteins and other valuable substances, so it is widely used for food purposes: in baking, confectionery industry, for production of groats, pasta.
Wheat bran is a concentrated feed for all kinds of farm animals and poultry. In 100 kg of bran correspond to 70-80 fodder units and contain 11 kg of digestible protein. Straw and chaff also have fodder value. Straw in chopped, steamed or chemically treated form is used for feeding cattle and sheep. 100 kg of straw contains 0.5-1.0 kg of digestible protein, 20-22 fodder units. Straw can be used as a building material, for making paper and bedding for animals. In some areas of Ukraine and the Central Black Earth zone, winter wheat is used for green fodder.
Cultivation areas and yields
In Russia before the Revolution, winter wheat was cultivated almost exclusively in the south. Nowadays, it is cultivated from the south of the Arkhangelsk region to the southern regions of Turkmenistan.
The main winter wheat crops are concentrated in areas with favorable overwintering conditions.
Winter wheat acreage in the USSR was about 6 million hectares in Ukraine and was located in forest-steppe, northern, central and southern steppe regions, about 5 million hectares in the Northern Caucasus, about 3 million hectares in the Central and Central Black Earth regions. Fertile Black Earth soils with sufficient precipitation during the growing season and a relatively warm winter created favorable conditions for high and stable yields in these regions.
Good conditions are also emerging in southern Kazakhstan, Central Asia, the Caucasus and the Central Black Earth zone. Fairly large areas for sowing winter wheat are concentrated in the Volga region.
In the central areas of the Non-Chernozem zone winter wheat acreage increased by the early 90s by more than 20 times compared with 1913. Large areas are sown in the Moscow, Bryansk, Kaluga, Vladimir, and Tula regions.
In the 1990s, winter wheat crops in Russia covered over 9 million hectares with an average yield of 2.0 t/ha. Modern varieties with a high level of agrotechnics allow for yields of 4-5 t/ha, including in the Non-Chernozem zone.
In 2001-2005 in Russia winter wheat was sown on 9 million hectares or 37% of the total area of wheat and 20% of the total area of grain crops. The gross harvest was 23 million tons, or 52% of the total wheat harvest and 29% of the total grain harvest. The average yield was 2.68 t/ha, for spring wheat it was 1.5 t/ha, and for all cereals it was 1.89 t/ha.
Among cereals, winter wheat with proper agronomic techniques gives high yields in many areas of its cultivation, primarily in the North Caucasus and Ukraine. In the farms of Rostov Region, the grain yield was 3.5-4.0 t/ha, in Krasnodar Territory, on average, more than 5.0 t/ha. In the Moscow region in the fields of the laboratory of crop production of the Moscow Agricultural Academy for many years in the seeded (occupied) fallows managed to get an average of 5.0-5.3 t / ha.
According to the experiments of the network of variety test plots, winter wheat has large reserves and opportunities to increase yields. According to long-term data, the yield on variety plots was 0.6-0.8 t/ha higher than on general massifs of the same farm, despite the fact that not all variety plots apply a complex of high agronomic techniques.
Biological features
Temperature requirements
Winter wheat seeds germinate at 1-2°C, but germination is slow. A temperature of 12-15°C is required for good germination, uniform emergence of seedlings and subsequent tillering. At 14-16 °C and sufficient moisture in the surface layer of the soil, shoots appear in 7-9 days.
The sum of effective temperatures during the sowing-sprouting period is 116-139 °C. The minimum temperature for the assimilation process is 3-4 °C. Under higher temperatures and other favorable conditions, carbon assimilation increases, but at 35-36°C the assimilation process slows down.
In the winter-spring period, winter wheat is sensitive to low temperatures and sharp fluctuations. In the south and southeast of the country, temperature fluctuations in early spring, when it rises to 5-10 °C during the day and drops to -10 °C at night, are dangerous. In the absence of snow cover, winter wheat dies at -16 … -18 °C. With a layer of snow of 20 cm, it can withstand frosts down to -30 ° C.
Modern breeding varieties are more resistant to low temperatures and can withstand winter frosts down to -25 … -30 °С.
Moisture requirements
Winter wheat is bushy in autumn and spring. Strong tillering is observed at sufficient moisture and temperature of 8-10°C. At temperatures less than 3-4°C and a lack of moisture, tillering stops. Bushiness increases with the addition of nitrogen fertilizers and with sowing of large seeds.
Before wintering, winter wheat forms 4-8 shoots, and embryonic roots reach 100-120 cm in length on chernozem soils. Increased temperature and lack of moisture in the soil in the spring have a negative effect on tillering. Late-forming stalks lag behind in earing and form a pod, which causes uneven ripening.
The root system is capable of penetrating to a depth of 1.5 m and makes good use of the moisture of the root layer. In the south of the country, soil moisture is the main factor for normal growth and development of plants in the period of seedlings and autumn tillering. When the moisture content in the 10 cm layer of soil is more than 10 mm, sprouts appear evenly. Plucking occurs more vigorously when there is at least 30 mm of available moisture in the 20 cm layer of soil. Autumn precipitation contributes to higher grain yields compared to straw yields. Spring precipitation leads to increased growth of vegetative mass and creates favorable conditions for the emergence of new shoots. During the period from spring awakening to earing, winter wheat uses about 70% of its total water requirement during the growing season; during the period from flowering to wax ripening, it uses 20%.
The highest productivity is observed when the soil moisture is 70-75% of the lowest (field) moisture capacity in the zone of the location of the main mass of the roots, that is up to 60 cm. Transpiration coefficient is 250-500.
Winter wheat is more drought-resistant than spring cereals due to earlier grain formation and better use of autumn-spring precipitation. However, with a dry spring, there may be a deficit of moisture, which occurs during the stage from the emergence of a tube to heading, i.e., during the period of intensive growth. From the beginning of spring regrowth to heading, wheat plants consume 70% of all water consumed during the growing season; from flowering to wax maturity, 20%.
Soil requirements
Winter wheat is characterized by high soil requirements. The reaction should be neutral pH 6-7.6. The highest and most stable yields are on fertile, well-moistened, weed-free black and dark chestnut soils. In the Non-Black Soil zone, lightly podzoled, medium-loam and gray forest soils are better suited. On light loamy, clayey, wet soils and drained peatlands are poorly suited. On poor sandy and podzolic soils on unfertilized fields and drought, tillering is severely inhibited.
Terrain has a major influence on yields. Low waterlogged areas are unfavorable for winter wheat.
The root system of winter wheat does not efficiently absorb difficult substances from the soil, so a deficit of phosphorus and potassium nutrition affects hardening and overwintering. Spring regrowth is slower than in rye, increasing the need for nitrogen fertilizers.
Vegetation
The growing season is 240-350 days. If the soil is well moistened, new roots form from the tiller nodes in spring, and this process may continue until the end of the milk ripeness of grain.
On chernozems, by the end of the growing season, the root system can reach a depth of up to 2.5 m; on less fertile soils, it is much less. On irrigated lands, most of the root system is formed in the moistened layer.
Emergence of tube in the middle belt of Russia occurs in the first half of May at a temperature not less than +10 °C, earing in 30-35 days. Earing rate increases with duration of daylight hours and temperature.
From spring awakening to earing in various climatic conditions of the country it takes 70-80 days. In the north, it is faster, since the daylight hours are longer in the spring.
Organic and nitrogen fertilizers lengthen the period until earing, phosphorus-potassium – reduce by 2-4 days.
At a temperature of +12 to +30 ° C flowering lasts 7 days, in hot and dry weather – 3-5 days. The manifestation of incomplete formation of grains in the spike contributes to strong winds, dry air, and drought.
Grain formation and ripening lasts about 30 days, depending on the variety and soil and climate conditions. For ripening, the optimum conditions are 50% humidity and temperature 16-21 °C. Dry weather shortens the ripening period, rainy and cool lengthens it.
The period from full ripeness to physiological ripening of grain is from 20 to 40 days.
Crop rotation
Winter wheat is demanding to predecessors. First of all, fields are timely released from fallow-occupying crops for soil preparation and sowing, weed control and techniques aimed at preservation and accumulation of moisture. Timely implementation of these techniques allows you to get early sprouts, good development of winter crops from autumn, which contributes to better overwintering and high yield.
Winter wheat predecessors in the rotation depend on soil and climatic conditions of cultivation.
In the zone of insufficient and unstable moisture the best forecrop is black fallow, which allows to provide accumulation of moisture, increase nitrates and other nutrients in the soil. Black fallow helps to increase the yield of wheat and obtain high-quality grain.
At the Zernograd State Breeding Station in the Rostov region, the average yield of winter wheat variety Bezostaya 1 for 10 years was 5.12 t/ha on bare fallows and 2.59 t/ha on non-fallow predecessors. In dry years the difference between bare fallow and non-fallow forecrop increases. In the average of 5 dry years for fallow crops yield was 4.76 t/ha, and for non-fallow predecessors – 1.37 t/ha. Grain protein content was 16% and 14.4%, respectively, and raw gluten – 34.6% and 32.8%.
The main reason for the decline in yields on non-fallow predecessors is the low supply of soil moisture. In addition, a dry autumn often results in delayed sowing. Underdeveloped autumn seedlings harden poorly and die in winter.
In the arid regions of the Southeast and the steppe regions of the South, strip fallows are important. High-stem crops are sown in fallow in summer, as they are less likely to dry out the soil than spring sowings. According to data for 4 years of the Kharkov Agricultural Institute, sunflowers are better suited for summer strips. In the experimental field, winter wheat in summer strips increased the yield by 0.5-0.6 t/ha.
The arid steppe of the North Caucasus is characterized by dry autumn, mild winter with little snow and repeated thaws, hot summer with strong dry winds. Ice crust often appears on winter crops and dust storms in early spring threaten crops. The yield of winter wheat on fallow lands in the arid steppe is 2-3 times higher than after corn.
Under irrigated conditions, yields are possible up to 6-8 t/ha without black fallow, in which case row crops and leguminous crops can be predecessors.
In the central, southeastern and southern regions of the steppe zone of Ukraine, in the south of Moldova, the steppe zone of the Northern Caucasus, in the middle and south-eastern parts of the Central Black Earth zone and in the Volga region to obtain a stable yield of winter wheat crops should be placed mainly on bare and black fallow.
Other precursors used in these areas include maize for silage, leguminous crops and annual grasses (except sorghum and Sudan grass), as well as winter cereals after black fallow.
Cereal crops, including winter wheat, should not be sown in the same field more than 2 years in a row, as the number of pathogens and pests, such as beetles, increases sharply.
According to the Krasnodar Research Institute of Agriculture, sowing two years in a row in the same field decreases the gluten content of the grain, reducing its vitreousness. However, fertilization improves grain quality.
In the zone of sufficient moisture the importance of seeded fallows, which allow you to receive additional production with a sufficiently good preparation of the field for sowing, fertilizers. Data from academic institutions and advanced farms confirm the economic efficiency of seeded fallows in this zone, but with the performance of the entire agricultural complex.
Seeded fallows are introduced taking into account the real possibilities of farms not to the detriment of the yield of cereal crops and subsequent crops.
In the Polesie region of Ukraine, Belarus, the Baltic states, in the northwestern and central regions of the Non-Black Soil zone, winter wheat can be placed after perennial grasses, vetch-oat mixture, lupine for green fodder and silage, early potatoes, and peas. These predecessors help to prepare soil for sowing in time and get good sprouts.
After leguminous crops, winter crops yield is usually lower than after fallow. Yields after winter cereals, barley, corn for silage, sunflower and other row crops are significantly lower.
In the forest-steppe regions of Ukraine, Moldova, the North Caucasus, and the Central Black Earth zone, winter wheat gives good yields in fallows occupied by clover, esparcet, vetch-oat mixture, peas, and early potatoes. In the more arid parts of the forest-steppe, it is better to sow wheat for seed purposes on black fallow.
In flax growing regions, winter wheat may be sown after flax if it is harvested early. In the Right Bank of Ukraine, the best predecessors are beet crops and winter rape.
On sandy and poor soils, green lupine fallow or occupied lupine fallow for fodder with subsequent plowing of crop residues may serve as a forecrop.
On sandy and sandy loam soils of Belarus, Ukraine and the central regions of the Nonchernozem zone as a suitable forecrop are green manure fallow, which is more often occupied by lupine, plowed in the phase of green beans.
In regions with sufficient and unstable moisture, such as the North Caucasus and Central Black Earth zone, due to relatively not severe winters, although unstable snow cover, there are more often favorable conditions for overwintering of winter crops. Summers are usually warm and humid. The highest yields of winter crops are obtained in bare, seeded, green manure and strip fallows.
In experiments of Voronezh Agrarian University it was found that the grain yield in the Central Black Earth zone in the rotation after bare fallow is 1.0-1.3 t/ha higher than in the corn fallow.
In the Middle and Lower Volga region characterized by harsh continental climate with dry autumn, little snowy winter, sharp temperature fluctuations in spring and dry summer. Under these conditions, occupied fallows and non-fallow predecessors do not allow to accumulate enough moisture for winter crops. Therefore, black and strip fallows are preferable.
In the steppe part of the Trans-Volga region good yields are possible only after bare cultivated fallows, with methods of snow retention. In the forest-steppe part of the Volga Provoregion, in addition to bare and strip fallows, annual grasses and corn for green mass can be good predecessors. Long-term experiments of Voronezh Agricultural University (Fedotov A.V., 1998) have shown that winter wheat yields in the steppe and forest-steppe zones are 1.5 times higher when strip crops are used.
The Non-Black Earth zone is characterized by sufficient moisture, in the northwestern areas – by excessive moisture. Winter is usually warm in the west, colder in the central part, and harsh in the east. Snow cover falls early, reaching a thickness of 30-50 cm. Soils are infertile, loamy and sandy loam of varying degrees of podzolization, often in need of increasing the state of cultivation. In this zone, winter wheat is optimally preceded by seeded and green manure fallows, perennial and annual grasses, corn for green fodder, peas for grain, and early potatoes. Wheat yields the same on clover as it does on bare fallow.
Fertilizer system
Winter wheat is demanding to soil fertility and responsive to fertilizers on all types of soils. To create 100 kg of grain and the corresponding amount of straw (150 kg) it uses on average 3.7 kg of nitrogen, 1.3 of phosphorus and 2.3-2.5 kg of potassium. Payment of 1 kg of fertilizer nutrients by grain yield increase can reach 10 kg. Microfertilizers are also effective for winter wheat: manganese, zinc, boron and copper.
According to the Myroniv Research Institute of Wheat Breeding and Seed Production, the yield of Mironovskaya 808 when sown after peas without fertilizer was 3.72 t/ha, while when applying N60P60K60 – 4.26 t/ha. When sowing the same variety without fertilizers, the yield was 1.3 t/ha, and with the addition of N60P60K60 – 2.5 t/ha.
In the experiments of the Krasnodar Research Institute of Agriculture Bezostaya 1 winter wheat at sowing after corn for silage without fertilizer was 2.98 t/ha, while when N90P45K45 was applied – 4.8 t/ha. The increase in yield per 1 kg of the active substance of the fertilizer was 10.1 kg.
Of particular importance are fertilizers, especially organic, on poor ashy soils of the northern and central regions of European Russia.
When calculating the norms of application for the planned harvest take into account the data of agrochemical charts, the removal of nutrients and the coefficient of utilization of nutrients by crops from the soil and fertilizers made. Norms are set with the account of meeting the needs of plants in the element of nutrition, the lack of which may lead to insufficient use of other elements. Good results are achieved with the fractional application of fertilizers, especially on the podzolized and leached chernozems and in the zone of sufficient moisture, when the main part of it is introduced during the plowing, some – with pre-sowing treatments, at sowing and as a top-up during the growing season.
Maximum nitrogen consumption by winter wheat is at the stages of emergence of a tube and ear emergence. Optimal nitrogen nutrition during this period allows spikelets to develop well, and the number of spikelets increases. Nitrogen nutrition increases protein content in grain.
Winter wheat absorbs phosphorus intensively during the first 4-5 weeks of growth. It has a great influence on acceleration of yield ripening, increase of size and volume of root system, especially in early stages of development: it promotes uniform appearance of shoots, rapid formation of root system. The highest consumption of phosphorus occurs in the first 30-35 days after germination of seeds, then its consumption is even. It is advisable to apply phosphorus fertilizer under the main cultivation and in the rows.
Potassium is more intensively absorbed during the period from the first days of growth to flowering. It contributes to better overwintering, increases resistance to diseases and pests, and affects the strengthening of stems. Its uptake continues for a short time in spring after growth resumes. Potassium fertilizer is advisable to apply in the fall under the main treatment.
Optimal phosphorus-potassium nutrition at the beginning of growth provides favorable conditions for rooting plants and the accumulation of sugars in tissues, protecting them from frost. Increased nitrogen nutrition in the first periods of growth and development, on the contrary, reduces resistance to frost and suffocation.
Nitrogen fertilizers are applied in autumn when placing wheat after non-fallow preceding crops and seeded fallows. Nitrogen is necessary for winter wheat, especially in the spring. If sufficient nitrogen nutrition is provided at this time, the plants begin to grow quickly, bush well, and form many productive stems.
Lime is an effective method on acidic and peaty soils. On poor soils, lime fertilizer is applied together with phosphorus and organic fertilizers. On sour peat soils rich in organic matter lime is made in conjunction with phosphorus-potassium fertilizers. Doses of lime are calculated on full hydrolytic acidity and, as a rule, are 4-9 t/ha.
Basic fertilizer
Organic fertilizers – manure and compost – are usually used as the basic fertilizer. Norm of half-decomposed manure for the southern steppe regions is 15-20 t/ha, in the Non-Black Earth zone – 25-30 t/ha. Rate of application of manure-phosphate compost – 15-20 t/ha, peat compost – 30-40 t/ha. If winter wheat is sown on seeded fallow lands, the basic fertilizer is applied under fallow-occupying crops, in this case mineral fertilizers are given.
According to long-term experience, the average increase in yield of winter wheat from making 20 tons/ha of manure in the Non-Black Earth zone is 0.6-1.2 t/ha, in the Central Black Earth zone – 0.2-0.8 t/ha, in the Volga – 0.2-0.5 t/ha, in the North Caucasus – 0.2-0.3 t/ha, irrigated lands – 1.0-1.2 t/ha. The greatest effect provides the joint introduction of organic and mineral fertilizers, especially phosphorus-potassium, as favorable conditions for microbiological activity are created.
When making a full mineral fertilizer on podzolic soils yield increase 0,8-1,0 t/ha, leached and thick chernozem – forest-steppe zone – 0,6-0,8 t/ha, ordinary and southern chernozem – 0,3-0,5 t/ha, the Northern Caucasus – 0,6-0,8 t/ha. The effectiveness of mineral fertilizers depends on moisture availability.
Organic fertilizers are effective not only on poor podzolic and sandy soils in doses of 35-50 t/ha, but also on chernozems in doses of 15-20 t/ha. Green manure gives good results. Under conditions of sufficient moisture on poor soils in combination with phosphorus-potassium fertilizers on the effect siderat (lupine, seradella) surpass manure. Green manure is most appropriate for irrigated lands.
A significant increase in yield, especially on chernozems, is achieved with the application of phosphorus fertilizers. The average yield increase from superphosphate application in Odessa agricultural experimental station was about 0.3 t/ha, in Kharkov – 0.35 t/ha, Rostov – 0.45 t/ha, Dnepropetrovsk – 0.5 t/ha, in the Non-Black Earth zone – 0.19 t/ha of grain.
Even greater effect is achieved by the introduction of phosphorus and potassium under the main tillage. This enhanced growth and development of plants, increases winter hardiness. Phosphorus-potassium fertilizers increase the content of hydrophilic colloids, sugars and nutrients in bush nodes to protect winter wheat from adverse conditions in winter.
When placed after non-fallow predecessors, the best results are achieved from the application of full mineral fertilizer.
Organic, phosphorus-potassium fertilizers and ameliorants are made under the main tillage of bare and seeded (occupied) fallows. Ameliorants are brought by machines РМГ-4, РУП-8, АРУП-8 under the discing before plowing, phosphorus-potassium fertilizers by the same machines before the manure. For the application of manure use ПРТ-10, РУН-15Б and others. The decomposed manure is applied immediately before plowing.
All potash and 80-90% of phosphate fertilizers is advisable to make under the plowing.
When sowing winter wheat on seeded fallow and after non-fallow predecessors on leached black earth, gray forest and podzolic soils additionally 30-50 kg/ha of ammonium nitrate are applied. Nitrogen fertilizers on bare fallow on which the manure was applied in the main reception is usually not made, because the accumulation of nitrogen reaches 80-120 kg/ha. On legume forecrop accumulates 30-60 kg/ha of nitrogen during the vegetation of wheat as a result of mineralization of humus accumulates 20-50 kg/ha. The remaining amount of nitrogen is introduced at the expense of mineral fertilizers based on the diagnosis of plant nutrition.
N30-45 nitrogen fertilizers are applied to seeded fallows and after non-fallow predecessors if the content of nitrogen in the arable layer is less than 30 kg/ha. They are applied under pre-sowing cultivation or top dressing from seedlings to the beginning of tillering.
Row fertilizer
In row fertilization the application of granulated superphosphate during sowing at the rate of 10-20 kg/ha of phosphorus is of particular importance.
According to the data of the geographical network of the All-Union Scientific Research Institute of Fertilizers and Agrosoil Science (VIUA), application of granulated superphosphate to the rows at the rate of 50 kg/ha for 12 years increased winter wheat yield by 0.27 t/ha on chernozem soils and by 0.34 t/ha on sod-podzolic soils.
Introduction of P10 into the rows gives the same increase of 0.3 t/ha of yield as an application of P33 under cultivation.
Granulated superphosphate is applied by combined seeding machines. Row application creates optimal conditions for plant nutrition, especially in the first phases of growth, the root system is better branched, the number of root hairs increases, which contributes to deeper root penetration and increases the winter hardiness of wheat.
Feeding (top dressing)
Feeding (top dressing) of winter wheat with mineral fertilizers is used as one of the available and effective methods of increasing the yield. It is carried out in spring and autumn. Spring fertilization is carried out as early as possible, when the plants begin to grow.
Under production conditions, it is not always possible to carry out spring feeding with fertilizer spread on the soil surface in optimal time over large areas. Therefore, feeding can be carried out with special grain drills, which embed the fertilizer in the soil (root feeding).
Root feeding is carried out across the rows of winter crops by СЗ-3,6 type seeders in a unit with a harrow. Mineral fertilizers are applied to a depth of 4-6 cm. Term of carrying out begins at creation of conditions for normal operation of seeders. Usually it falls on later period than early spring fertilizing.
According to generalized data, yield increase of winter wheat from root feeding is 0.34-0.53 t/ha. The importance of such top dressing increases due to the introduction of intensive varieties that require higher doses of fertilizers. It has a decisive importance in the south-east of Russia, where the optimal timing of spring feeding passes very quickly.
Approximate rates of top dressing are 40-60 kg/ha and depend on soil and climatic conditions and the condition of winter crops. When feeding, take into account the time of resumption of spring vegetation: at early stages of vegetation nitrogen fertilizer application rates decrease, at late stages – increase.
Autumn fertilizing of winter wheat in the placement on the non-fallow predecessors is carried out on poor soils and with no pre-sowing fertilization.
To improve the quality of grain foliar feeding (from aircraft) during flowering – the beginning of grain filling is used.
At Genic Experimental station foliar fertilization with urea at the beginning of the phase of the milky state of the grain at the rate of 60 kg/ha of nitrogen increased the yield by 0.15 t/ha, the raw gluten content – by 2.4%.
According to the data of the State Commission for Variety Testing of Agricultural Crops, foliar dressing in the phase of earing with nitrogen fertilizers at the rate of 30-40 kg/ha a.s. in 12 experiments conducted on the variety plots of the Non-Black Earth zone, increased the protein content in grain by 1,1- 2,5%, crude gluten – by 2-4%.
Early spring nitrogen fertilization during tillering increases crop height and density, but has little effect on grain quality. It is carried out immediately after snowfall with ammonium nitrate at a dose of 30-40 kg/ha of nitrogen. This feeding is especially important if the crops were placed on the occupied fallows or non-fallow predecessors. Nitrogen fertilization is not carried out at the placement of crops on the fallow, on which the manure with a sufficient supply of nitrogen in the soil was applied, and the plants are well over the winter. Feeding such crops is more effective to carry out later, in the root method.
The total dose of nitrogen, which is applied in autumn and spring during the tillering phase, should be 30-35% of the total amount. If possible, N50-80 (40-50% of the total dose) is applied at the beginning of the emergence of the tube phase. This dressing affects the number of grains in the ear. Under conditions of sufficient moisture, ammonium nitrate can be applied on the surface, which is somewhat cheaper than foliar feeding. In dry weather, by contrast, it is advisable to foliar feeding 15-20% solution of urea, and at the same time at one time make no more than N30, to prevent the emergence of oily leaves.
Based on the results of the diagnosis of nutrition in the earing or ripening phase, foliar nitrogen feeding with urea to improve the quality of grain. For this purpose, boom machines such as ОПШ-15-01, ОПМ-2001, ОП-2000-2 can be used. Norm of urea solution consumption is 200 l/ha. When foliar feeding, microelements and sodium humate are also added at the rate of 50 g/ha.
Fertilizing is carried out in the morning or evening hours at a temperature of +20-22 °C. The highest efficiency of feeding is achieved when it is carried out taking into account the results of plant nutrition diagnostics.
Microfertilizers
Copper and boron fertilizers are used for winter wheat on sod-podzolic and gray forest soils. Manganese and zinc fertilizers are used on black and chestnut soils.
For pre-sowing wetting of winter crops seeds:
- manganese sulfate – 700-900 g/t seed;
- copper sulfate – 800-1000 g/t seed;
- zinc sulfate – 800-1000 g/t seed;
- cobalt sulfate – 400-500 g/t seed;
- ammonium molybdate – 600-800 g/t seed.
To reduce costs, treatment with micronutrients is combined with dressing and treatment with growth regulators. Film-forming compositions, such as 2% aqueous solution of sodium carboxymethylcellulose salt (Na-CMC), are used for better fixation on seeds.
For foliar feeding of winter and spring wheat with microfertilizers are used:
- boric acid – 110 g/ha;
- sulfuric acid manganese – 220 g/ha;
- sulfuric copper – 330 g/ha;
- molybdenum ammonium – 600 g/ha.
Micronutrient feeding is combined with nitrogen applications, herbicide treatments and growth regulators.
Nutrition diagnosis of winter wheat
Visual diagnosis
Visual diagnosis of winter wheat nutrition allows us to determine mineral starvation on the basis of morphological signs of plants.
Nitrogen deficiency appears in autumn in the tillering phase. In this case, small leaves of pale green color are observed, with severe starvation, their tips show yellow with a pink tint, and later they die off. In such plants, tillering is weak or absent, the stem is thin and short, the ear and grain are small, ripening comes early, the yield is low.
Phosphorus starvation may appear in the phase of three leaves. The tips of the leaves turn red-purple, while the rest of the leaves turn dark green with a bluish tint. The same coloration is observed on the stems. The leaves are small and narrow, and the lower ones gradually wither away. Flowering and ripening are delayed by 5-10 days, and the yield is reduced.
Lack of potassium leads to the appearance of pale green coloring, turning brown, and dying of the edges of leaves, the so-called marginal burn. Low, weak, lodging stems and drooping ears can be observed.
Magnesium deficiency can manifest itself in the fall. The tips of the lower two or three leaves turn a dark red color, and then the whole leaf surface acquires this color, except for the upper leaves, which have a pale green color. During the growing season, the leaves are narrow, curled into a tube, ripening is delayed, and yields are reduced.
Manganese deficiency is manifested by chlorosis between leaf veins, the veins themselves, including small ones, remain green.
Copper deficiency is manifested by rapid turning white and drying of leaf tips. Sick plants bush intensively, leaves twist and curl into a spiral, the ear is crooked, grain formation is poor.
Under iron deficiency, old leaves remain green, young ones are uniformly chlorotic between veins, the color pale green or yellow, without tissue death.
If any nutrient is deficient, yields are reduced.
Soil diagnostics
Soil diagnostics of winter wheat nutrition is carried out in autumn and spring. For this purpose, the content of mineral nitrogen available to plants is determined in the root-containing soil layer up to 1 m deep. Soil samples are taken with a drill in layers of 20 cm to a depth of 60 cm in autumn and up to 100 cm in spring. Three to five samples are taken from each field to determine nitrogen content in layers 0-40, 0-60 and 0-100 cm.
If the content of nitrogen in the pre-sowing period in the arable layer less than N30, then make N20-30, that is 20% of the total amount, in autumn under the main tillage, pre-sowing cultivation or on sprouts. If the nitrogen content is higher, it is not applied to prevent overgrowth of plants. The dosage of nitrogen dressing in early spring is defined as the difference between the amount required to obtain the planned yield and the mineral nitrogen reserve in the meter layer of soil in spring. For nitrogen fertilizing in early spring, apply no more than N30-45. If the calculated dose is more than N60, it is applied fractionally in the phases of tillering (spring), emergence of a tube and ear emergence.
Leaf diagnostics
Leaf diagnostics of winter wheat nutrition is carried out in the phases of tillering, emergence of a tube and ear emergence. For this purpose, 100 g samples of plants are taken at 20-30 points along the diagonal of the field. In the phases of tillering and tubing, whole plants are cut off at the soil surface; in the earing phase, only three upper leaves from 150-200 plants are taken. Total nitrogen and phosphorus are measured in the samples.
To calculate the dose of nitrogen or phosphorus top dressing, the results of analyses are compared with the optimum content of elements in leaves for a particular growth phase. Correction factors are derived for each phase by dividing the optimal indicators by the actually obtained. Depending on the phase, the optimal nitrogen content in leaves is as follows:
- tillering – 5.0-5.5% per absolute dry matter;
- emergence into a tube – 4,6-5,0 % of absolutely dry matter;
- earing – 3.0-4.5 % of absolutely dry matter;
For phosphorus:
- tillering – 0.55-0.60 % per absolutely dry matter;
- emergence into the tube – 0.45-0.50 % of absolutely dry matter;
- earing – 0.35-0.45 % of absolutely dry matter.
Tissue diagnostics
Tissue diagnostics of winter wheat nutrition allows predicting grain quality and determining the need for foliar nitrogen supplementation. It is carried out at the end of the phase of emergence of a tube.
The method is based on determining the content of nitrates in the stems by the intensity of diphenylamine staining of juice. For this purpose, 100-120 stems are cut in the morning at 20-30 places along the diagonal of the field, from which an average sample of 20 pieces is formed. A 1.5-2.0 mm thick stem plate is cut with a blade at a 45° angle on each stem above the second internode at 10-15 mm. The slices are placed on a slide, and one drop of 1% diphenylamine solution is applied to each. After that, another slide is placed on them and the sap is squeezed out of the tissue of the slices by pressing with the fingers.
The results are evaluated by comparing the intensity of blue staining with the reference scale. Each stem is scored from 0 to 6. If the average score is less than 3.5, foliar feeding is ineffective because it will not produce strong wheat. At a score of 3.5-4.5 two foliar feedings at the earing-flowering and grain filling phases by N30 are carried out. With an average score of 4.6-5.4 one feeding during earing-flowering is carried out. At a score of more than 5.5 foliar feeding is not required.
Tillage system
Main article: Tilling for winter crops
The tillage system is developed taking into account the preceding crop, weed infestation of the fields and the area of cultivation. Winter wheat is responsive to the depth of plowing. Deepening of the tilled layer is carried out during autumn tillage under the forecrop with the simultaneous introduction of organic fertilizers in high doses. On sod-podzolic soils with shallow topsoil good results gives loosening or inclusion in the tillage subsoil horizon. The depth of the layer included in the tillage is determined by the thickness of the arable layer, the podzolization of the soil and the norms of organic fertilizers.
Deepening of arable layer increases water supply, aeration, nitrate and soluble phosphate content.
The conditions for obtaining high yields of winter wheat on seeded fallow are the high agricultural technique of the fallow-occupying crop and its timely harvesting. After harvesting crops of solid crops depending on soil compaction, tillage is carried out with ploughs with skimmers and simultaneous harrowing or cultivation. After harvesting of row crops the field is cultivated and harrowed.
In years with a dry summer and autumn period, surface tillage by disc or hull tillers without mouldboards with simultaneous harrowing and rolling is more effective. The exceptions are heavy soils with a heavy granulometric composition, prone to swamping, and fields clogged with root weeds.
There should not be a big gap between harvesting of forecrop and tillage, as the soil can dry out during this time. According to the Myroniv Research Institute of Wheat Breeding and Seed Production, the yield of winter wheat when plowed immediately after harvesting corn for silage on August 10 was 6.3 t/ha, August 20 – 4.94 t/ha and September 1 – 4.34 t/ha.
Tillage of black fallow is started immediately after harvesting the preceding crop. In the presence of stubble, single discing to a depth of 6-8 cm is carried out. If the fields are clogged, discing to a depth of 6-8 cm and discing (with half-spherical discs) to 12-14 cm is carried out. After 2-3 weeks do plowing to a depth of 25-27 cm plow with skimmers. For weed control and moisture accumulation perform in the spring and summer period, 4-6 layered different-deep cultivation with 10-12 cm, reducing to 5-6 cm. In dry weather the simultaneous cultivation with rolling is carried out.
During flat-cut tillage to control weeds include treatment with herbicides.
The early fallows are plowed in spring until May 15, the depth of 20-22 cm, further processing is similar to the treatment of bare fallows. The occupied fallows are processed depending on weather conditions and preceding crops. With wet well-crumbly soil apply conventional plowing to a depth of 18-20 cm. On dry soil carry out surface tillage, such as БДТ-7,0, БД-10, БДТ-3,0, ЛДГ-5А, ЛДГ-10А, ЛДГ-15А, ЛДГ-20А, КПЭ-3,8А.
In the Non-Black Soil zone once every 3-4 years the plowing is replaced by deep chiseling at 35-45 cm to loosen the plow pan.
In dry years after sowing winter wheat, soil is rolled with light harrowing. Rolling promotes uniform emergence of seedlings, normal development and eliminates the possibility of soil subsidence, improving the conditions for overwintering.
Plowing is carried out as early as possible after cereal predecessors. Early plowing with simultaneous harrowing contributes to moisture retention in the soil, reducing clumpiness. Before sowing in case of weeds appearance 2-3 cultivations with harrowing are carried out. The first cultivation should be deeper, the pre-sowing one – to the depth of sowing seeds. This method of tillage after cereals is close to the tillage of bare fallow and is called semi-fallow tillage (half-fallow), especially it is widely used in the south.
In some areas, large areas of land are at risk of wind erosion. For example, in the steppe regions of the North Caucasus, southern Ukraine, insufficient and unstable moisture Central Black Earth zone, strong winds lead to the destruction and blowing of soil, cause dust storms, damaging winter crops and, often, lead to the complete death of the crop. Therefore, the anti-erosion tillage system is used in these areas.
The anti-erosion system of tillage is widely used in Northern Kazakhstan and Western Siberia. It consists in non-moldboard (flat-cutting) tillage with keeping most of the crop residues on the soil surface. For non-moldboard tillage are used flat-cutter type КПГ-250А, КПШ-9, which cut the roots of crop residues and loosen the soil to a depth of 8-30 cm; cultivator-deep loosener КПГ-2,2; rod cultivator КШ-3,6А, designed for tillage to a depth of 5-10 cm, needle harrow type БИГ-ЗА for loosening, which almost does not damage the stubble. Sowing is carried out by СЗС-2,1 stubble seeder, which simultaneously with sowing trims weeds with cultivator tines and rolls the soil in the seeded rows.
In all zones of Russia, predecessors should release the field as early as possible. So in the Non-Black Soil zone – 3-4 weeks before sowing, in southern areas – 1,5-2 months, for good soil preparation. After peas, corn for silage and other predecessors fields are cultivated as they are released disc tools like БД-10А, БДТ-7,0, ЛДГ-10А to a depth of 8-10 cm or flat-cutters КПШ-9, КПГ-2,2 to 10-16 cm. After peas, both methods are used, after corn the first method is preferred, which is carried out with heavy disc harrows in 2-3 trails, followed by removal of needle harrows БИГ-3А and ring-spiked rollers. It is important to comply with the timing, avoiding gaps.
In dry years, it is effective to use combined aggregates РВК-3,6, АКП-2,5, which in one pass lead to loosening of the upper layer at 6-8 cm needle or spherical discs; the lower layer at 8-16 cm – flat-cutters, followed by leveling the surface with a dragging harrow and a roller.
After perennial grasses conducted discing, and then plowing to a depth of 20-22 cm plows with skimmers with simultaneous rolling ring-spiked rollers (ЗККШ-6) or plows equipped with devices ПВР-2,3 or ПВР-3,5.
Presowing soil preparation consists in loosening of the surface layer to a fine crumbly state and leveling. Tillage is carried out at an angle to the direction of main tillage with shuttle motion of the machine. Presowing cultivation is carried out with flat-cut working tools to the depth of 5-6 cm with harrows and plumes to reduce moisture loss and improve the quality of seeding.
Sowing
Seed preparation
Seed quality is one of the most important conditions for high yields. Plants grown from large seeds lay the tillering node deeper. This is evidenced by the data of the Ukrainian Research Institute of Plant Industry, Breeding and Genetics for 4 years.
The depth of the tillering node affects the overwintering of plants: the deeper the tillering node is laid, the higher the winter hardiness of winter wheat.
Plants grown from large seeds develop a stronger root system, grow faster, are less affected by drought, are more resistant to disease, and produce higher yields. It is generally accepted that seeds with growth strength of at least 80%, which is close to field germination, are suitable for sowing.
Table. Effect of seed coarseness on the number of seedlings and tiller node location at different sowing depths[1]Plant breeding/P.P. Vavilov, V.V. Gritsenko, V.S. Kuznetsov et al. Gritsenko, V.S. Kuznetsov et al; Edited by P.P. Vavilov. - M.: Agropromizdat, 1986. - 512 p.: ill. - (Textbook and textbooks for … Continue reading
According to P.P. Lukyanenko, in the Krasnodar region when sowing winter wheat variety Bezostaya 1 with a mass of 1000 seeds equal to 45 g, received a yield of 5.02 t/ha, while when sowing seeds with a mass of 1000 pcs. 47.8 g – 5.42 t/ha.
Protein content in seeds affects the rapidity of growth and development of vegetative mass, later on the development of generative organs of the plant. In irrigated areas of Kyrgyzstan, when sowing winter wheat with grain protein content of 18.6%, the yield was 3.64 t/ha, while at 15% protein content – 2.85 t/ha.
In many areas of the Non-Black Soil Zone, where the period between harvesting and sowing of winter crops is short, the stocks of seeds of the previous year’s harvest are left – a carry-over fund of seeds. For example, sowing winter crops with freshly harvested seeds, which may be physiologically immature, in the Baltic countries, Belarus, in the Northwestern Central, Volgo-Vyatsky and Ural regions leads to sparse seedlings and poor plant development.
According to the Kostroma State Regional Agricultural Experimental Station, when sowing winter wheat variety Mironovskaya 808 with seeds from the carry-over fund yield was 4.35 t/ha, while freshly harvested – 3.87 t/ha.
If you want to sow freshly harvested seeds with low germination, but high viability, it is necessary before sowing to warm the seeds in the sun for 3-5 days or in a dryer at 45-48 ° C for 2-3 hours. According to the Experimental Field Station of the Moscow Agricultural Academy, the yield increase with this method of preparation of freshly harvested seeds was 0.43 t/ha.
To disinfect seeds from spores of smut, it is carried out dressing Granozan with dye in a dose of 1-2 kg/t seed or pentathiuram in a dose of 1.5-2 kg/t seed.
To control smut, it is necessary to use a thermal treatment consisting in soaking the seeds in water at 28-32 °C for 4 hours, followed by heating them for 8 minutes at 52 °C. Or thermochemical treatment of seeds by soaking them in granosan solution (1 g per 4 liters of water) at 45 °C for 3 hours, followed by cooling and drying. Seed treatment with Vitavax or Kinolat 15 in doses of 2 kg/t seed gives good results.
Treatment of seeds with Tur (chlorocholine chloride) in a dose of 5 kg/t seeds is an effective method of seed preparation. Such treatment contributes to deeper establishment of tillering node, formation of powerful and deeply penetrating root system. This increases the resistance of winter wheat to unfavorable conditions of overwintering and lodging, the yield increases by 0.2-0.5 t/ha.
According to the experiments of the All-Russian Research Institute of Corn, treatment of winter wheat seeds of Bezostaya 1 with a solution of tur with simultaneous dressing improved the overwintering of plants and increased the yield. Thus, the percentage of death of plants whose seeds were treated with a 10% solution of tur and granozan (1 kg / t) decreased to 14% (the control – 34%), the yield increased to 2.25 t/ha (the control – 1.82 t/ha). Control – seeds treated only with Granozan (1 kg/t).
When treating seeds with the preparation Tur emergence of shoots is delayed by 1-2 days, so the optimal time for sowing is the dates accepted in the area. Experiments of Kurgan agricultural institute showed that treatment of seeds with Tur by 7% more economical than spraying of crops.
Tur (chlorcholine chloride) was used as a growth regulator for high-growing varieties of wheat. At present, retardant CeCeCe 460 is used in the dose of 5 kg per 1 ton of seeds.
Retardants contribute to deeper formation of tillering node. If there is a risk of overgrowth of winter crops in autumn, additional treatment of crops is carried out. To prevent lodging, treatment of crops with this drug is carried out in spring in the tillering phase.
Timing of sowing
One decisive factor in winter overwintering of winter crops is optimal sowing dates. Sowing too early, especially on fertilized bare fallow, where plants with good water and nutrient regimes overgrow, reduces frost and winter hardiness, leading to a sharp decrease in yields.
With late sowing dates, winter crops often do not have time to gain enough strength for normal overwintering. Even under good conditions, they become thin and lag behind in growth and development in spring.
According to the All-Union Scientific Research Institute of bast crops Sumy region, when sowing winter wheat variety Ilyichevka on the occupied pair September 5 yield was 2.81 t/ha, September 10 – 2.36 t/ha, September 20 – 0.59 t/ha.
Different varieties respond differently to the timing of sowing. For example, according to long-term data Sinelnikovskaya selection and experimental station (Dnipropetrovsk region).
Table. Effect of sowing dates on yield (100 kg/ha) of winter wheat (predecessor black fallow)[2] Plant breeding/P.P. Vavilov, V.V. Gritsenko, V.S. Kuznetsov et al; Edited by P.P. Vavilov. - M.: Agropromizdat, 1986. - 512 p.: ill. - (Textbook and textbooks for higher education institutions).
| Bezostaya 1 | |||||
| Mironovskaya 808 | |||||
From the above data, we can see that the optimal sowing date of the variety Bezostaya 1 on black fallow is less long and comes later than in Myronivska 808. When deviating from the optimal dates in either direction, the yield of both varieties, especially Bezostaya 1 decreases.
Based on the biological characteristics of the crop and differences in resistance to adverse conditions of overwintering, L.I. Nosatovsky substantiated the optimal sowing dates of winter wheat. This crop overwinters better and gives the highest yield when the plants form 3-4 stems by the time of wintering. At this stage, wheat has a well-developed aboveground part and root system, and it accumulates a large amount of plastic substances. Such plants can survive harsh wintering conditions and are more resistant to rust and pests. To ensure that plants go to winter in the phase of 3-6 stems, it is necessary to sow winter wheat in terms of 45-55 days during its fall vegetation, and the sum of average daily temperatures from sowing to stable passage through 5 ° C – 550-580 °C.
In the Non-Black Soil zone and in the Southeast of Russia, bushiness is favorable for overwintering – 3-4 stems, in the Central Black Earth zone and in the North Caucasus – 4-6 stems per plant. The highest yield is given by plants which have formed two full ears with a large grain and a total bushiness of 5-6 stems before the harvest. The latest sowing date of winter crops is when the sum of active temperatures before the average daily air temperature rises above +5 °C – 250-270 °C.
Optimal timing of sowing coincides with establishment of average daily temperature of 17-14 °C. When sown at these times, winter wheat is less affected by Hessian and Swedish flies and is more resistant to diseases that develop at higher temperatures. Based on data from research institutions, the following are considered the most appropriate sowing dates for winter wheat:
- Far North (north of 60 °N) – 1-15 August. Karelia, Kirov and Perm regions – August 5-10.
- Non-Black Soil zone – August 10-30.
- Central Black Earth zone – August 20-September 10. Forest-steppe and southeastern part of the zone – August 20-September 1.
- Southern steppe zone, Lower Volga – September 1-20. Southern Volga – October 1-10.
- Northern Caucasus – October 1-10.
- The Crimea and foothill areas of the Northern Caucasus – September 15 – October 5.
However, at each farm these dates should be specified depending on the variety, soil conditions, moisture and fertility, pest distribution and meteorological conditions of the year.
Sowing methods
In production practice, the row method with a row spacing of 15 cm, narrow-row with a row spacing of not more than 10 cm and cross-row methods are usually used, which allow seeds to be evenly distributed over the area due to which plants develop better, less oppress each other, increase productive bushiness and power of root system, more fully use light, moisture, nutrients and give higher yields. According to numerous data, narrow-row and cross-cropping methods compared to conventional row sowing give an increase in yields on average 0.2-0.4 t/ha, sometimes more.
Production tests of stubble seeders when sowing winter crops for several years in the southern regions showed that their use provides a yield increase of 0.2 to 0.6 t/ha. In the Leninsky district of the Crimea, the yield of winter wheat Bezostaya 1 on seeded fallow land when seeding planter СУК-24 was 4.35 t/ha, while the stubble seeder СЗС-9 was 5.18 t/ha.
Sowing by stubble seeders allows to sow seeds in moist soil layer, to receive more uniform sprouts, contributes to accumulation of moisture and snow in furrows formed by coulters and packing rollers of seeders.
Production tests of rowless seeders allowing uniform distribution of seeds over the area and their good embedding have shown greater efficiency of the rowless method of sowing.
In the zone of excessive moisture (North-West) winter crops are ridge seeding, especially on heavy soils. Ridge sowing protects plants from stagnation and excessive water, improves air and heat regimes of soil, creating more favorable conditions for aerobic microbiological processes.
At present, the winter crops are sown with leaving “technological track”, coupling of three seeders СЗП-3,6 or СЗ-3,6. When seeding overlap two coulters in the alignment of the wheels (tracks) of the tractor, resulting in an unsown “technological track” width of 45 cm for the subsequent passage of the tractor and agricultural machinery for the care of crops.
The direction of the rows when sowing is determined by the topography, as a rule, they are located from north to south. Plants in this case, the plants better use the morning and evening sunlight, and in the midday hours less affected by overheating, the yield for this method increases by 0.2-0.3 t / ha.
For seeding, seeders С3-3,6А, СЗУ-3,6, СЗТ-3,6А, СПУ-3, СПУ-6 or foreign variants are used. In arid areas and at risk of wind erosion, stubble seeders-cultivators are used, such as СЗС-6; СЗС-8; СЗС-12; СЗС-14, which leave crop residues on the soil surface, reducing the wind speed over the surface and prevent blowing.
On slopes, sowing rows are placed transversely to increase the retention of meltwater and stormwater, reducing water erosion of the soil.
The technology of leaving technological strips in the crops was developed in the USSR in the 1980s. It is used in various variants in European countries in intensive farming. However, it is not widespread in Russia. To reduce the manifestation of erosion processes, winter wheat crops with permanent technological track are placed on level fields. When the slope is steeper than 3°, sowing is carried out across the slope, in the fields with complex topography technological track is not made.
For rectilinear sowing, the first pass of the machine is made along the drawn straight line.
Seeding rates
Seeding rates depend on climatic and soil conditions. Denser seeding is used in the northern humid areas, more sparsely in the south and especially in the southeastern arid areas. In the northern humid areas, the main factors determining the optimal seeding rate are light and soil fertility, and in the arid areas, the provision of moisture. The less moisture in the soil, the less dense the crops should be. This is why seeding rates decrease when moving from north to south and from northwest to southeast. When cultivating winter wheat under conditions of irrigated agriculture in arid areas, the seeding rate increases.
There is no unambiguous assessment of the dependence of seeding rates on soil fertility. Contradictory recommendations are related to the fact that experiments to establish this dependence were conducted in different soil and climatic zones, with different varieties and on different soils.
The dependence of seeding rate and fertility is different in different zones of the country. In humid areas, where high seeding rates are adopted, the fertilized fields show increased tillering, which leads to thickening of crops, lodging and reduced yields. Therefore, in these areas with a high agricultural background, it is advisable to slightly reduce the rates, especially for strongly bushy varieties. In arid areas, where more sparse crops are used and there is a weak tillering, when creating good conditions for the development of plants, ie on soils rich in nutrients, it is recommended to increase the rates of seeding, as plants in this case more economically consume moisture.
Varieties react differently to seeding rates. According to long-term data of the laboratory of plant breeding of the Moscow Agricultural Academy, at an increased level of nutrition, the optimum seeding rate is lower than at the normal level by 1 million/ha of germinating seeds and was for the variety Mironovskaya 808 – 4.5 million, for the variety Mironovskaya Jubilee – 5.5 million.
Changes in seeding rate for narrow-row and cross-row methods of sowing are also ambiguous, but most researchers are inclined to increase by 8-15% of the norm, with wide-row – to reduce by 30-50% of the usual rowing.
When setting the seeding rate, sowing dates are taken into account: if they are delayed, the rate is increased. In this case, the thickened crops develop and mature faster, which reduces the risk of dry winds in the arid zone or damage of unripe crops by autumn frosts in the northern areas. On clogged fields the seeding rate should also be higher than on clean ones.
Seeding rate is expressed in kilograms per hectare or number of germinated seeds (number of millions of seeds per 1 hectare). In determining the weight norms do not take into account the coarseness of seeds, so depending on the weight of 1000 seeds you get different feeding areas per plant. A more correct definition of seeding rate is by the number of germinating seeds per hectare. In this case, when sowing seeds of different size, the same area of nutrition per plant is allocated.
Approximate seeding rates of winter wheat recommended for different zones by experimental institutions and practice:
- Non-Chernozem zone – 5.5-6.5 million/ha of germinating seeds (180-200 kg/ha);
- Central Black Earth zone – 4.5-6.0 mln/ha of germinating seeds (160-180 kg/ha); forest-steppe zone – 5.5-6.5 mln/ha of germinating seeds;
- Right-bank Volga region – 4.5-5.5 mln/ha of germinated seeds;
- Left bank Volga region – 3.5-4.0 mln/ha of germinated seeds;
- Northern Caucasus: foothill steppe – 3.0-4.5 million/ha of germinating seeds (140-160 kg/ha), mountainous part – 4.5-6.0 million/ha of germinating seeds (160-180 kg/ha);
- Ural, Siberia – 5.5-7.0 mln/ha of germinated seeds;
- Belarus – 5.0-6.0 million/ha of germinating seeds;
- Ukrainian Polissya – 4.5-5.0 million/ha of germinating seeds;
- Forest-steppe and steppe of Ukraine – 4.0-4.5 million/ha of germinating seeds;
- Baltic countries – 5.0-5.5 million/ha of germinating seeds.
Optimal seeding rates should be specified for each individual farm and variety.
Depending on the predecessor, the following seeding rates are recommended:
- bare fallows – 3.5-4.5 million germinated seeds per 1 hectare;
- seeded fallows – 4.5-5.0 million germinated seeds per 1 ha;
- non-fallow predecessors – 5-6 million germinating seeds per hectare.
Under favorable conditions the lower recommended limit is used. Poor soil preparation, lack of fertilizers, late sowing dates, and errors in agricultural technology are not compensated by higher seeding rates.
Sowing depth
The sowing depth of winter wheat seeds affects the completeness and timing of emergence of seedlings, the depth of the tiller node, winter hardiness, productive bushiness and, accordingly, yields. Sowing depth is determined by many factors, especially soil moisture and mechanical composition.
Winter wheat requires a relatively deeper seed embedding, which deepens the tillering node. Shallow embedding increases the risk of freezing and suffocation. On black earth soils and in arid areas, seeds are sown to a depth of 5-6 cm. When the upper soil layers dry out strongly, the embedding depth on chernozems can be increased to 8-10 cm. In the Non-Black Soil zone on heavy clay soils prone to strong swamping and compaction, the embedding depth is usually 4-5 cm, on medium-cohesive – 5-6 cm.
In general, for winter wheat it is biologically favorable to sow to a depth of 3 cm when there is enough moisture in the sowing layer. The maximum sowing depth for all crops is equal to the coleoptile length, for winter wheat respectively 7-8 cm. The larger the seeds, the better they tolerate deep embedding. The optimal sowing depth of winter wheat seeds is considered to be 4-6 cm, a further increase leads to a decrease in field germination.
Crop care
The main methods of winter wheat crops care include rolling, feeding, snow retention, spring harrowing, weed, pest, disease and lodging control.
When sowing winter wheat in poorly moistened or loosened unsettled soil it is necessary to roll with ring rollers ЗККШ-6. Rolling contributes to a better contact of seeds with the soil, the transfer of moisture from the lower to the upper layers, which contributes to the rapid and uniform emergence of seedlings and a good autumn tillering. According to the Krasnodar Research Institute of Agriculture, this method increased the yield by 0.22 t/ha. To reduce the risk of damage to overgrown winter wheat, plants, if they are not spread out, are mowed in autumn by one-third of the height. The cuttings are removed from the field immediately to prevent mold from developing on the plants. Mowing is carried out in time to allow plants to get stronger before the steady cold. Grazing on winter crops is not allowed.
In the northwestern areas of the Non-Black Soil zone, frequent autumn rains may severely overwater the soil. Prolonged stagnation of water on the fields may lead to the autumn soaking of crops. To prevent soaking and remove excess moisture in the fields, make furrows at a slight slope.
In autumn, after stopping of vegetation, to prevent development of snow mold and root rot, treatment of crops with Fundosol at the rate of 0.3-0.6 kg of preparations per 1 ha is carried out.
An effective method of snow retention in steppe and forest-steppe areas is field protective forest strips, in arid and low-snow areas – strip fallows. As strip crops, tall plants such as sunflower, mustard, and southern hemp are used. These crops are sown in a fallow 1-1.5 months (July 15-20) before sowing winter wheat with 60-70 cm rows by 2-3 rows. The distance between striped rows is 10-20 m perpendicular to the direction of the prevailing winter winds. Seeding rate for sunflowers is 20-25 seeds per 1 running meter, for hemp 40-50 fruits.
Strips may be sown along a future technological track; in this case the sowing is carried out along strips and in spring a technological track is rolled over them. Waders increase winter wheat yield by 0,3-0,5 t/ha.
To prevent formation of ice crust and to prevent getting soaked in spring, the pre-growing slitting with a unit ЩН-2-140 is carried out, which reduces runoff and increases moisture stocks in the soil.
Spring harrowing is carried out to break the soil crust, remove dead and damaged plants as well as weeds, which may be a hotbed of pests and diseases. Harrowing is carried out after the soil surface has dried up a little. Harrowing is carried out across the rows or diagonally. On underdeveloped crops and light soils, one harrow, on well developed crops and heavy soils, two harrows. Spring harrowing increases the yield by 0.2-0.3 t/ha. In the case of bulging plants, instead of harrowing, rolling is carried out.
Feeding winter wheat with nitrogen fertilizers is carried out in 2-3 applications: in early spring – at the beginning of vegetation, in the bush phase – root and in the earing phase – to improve grain quality.
Plant protection system
To develop a plant protection system, a phytosanitary assessment of crops is carried out. In intensive agro-technologies, an integrated system of protection is used, which provides for the integrated use of organizational and economic, agrotechnical, biological and chemical methods. Agrotechnical control measures play the leading role in the integrated system of protection. Chemical control methods are used as an additional measure. It is necessary for crops with heavy weeds (more than 20 small and one perennial species per 1 m2).
Development of winter wheat in spring is slow, so crops are easily overgrown with weeds. Chemical methods are used to control it. In autumn, the crop is sprayed after sowing before sprouts appear with simazine at a dose of 0.25 kg/ha a.s.
On winter wheat crops, 2,4-D herbicides are used, such as 40% amine salt at a dose of 1.5-2.5 kg/ha, 10-12 kg/ha of butyl ether granules, and 1.9-3 kg/ha of Dialen. Crop treatment is carried out in spring in tillering phase at air temperature 12 to 25 °C, the rate of solution consumption during ground spraying – 200-400 l/ha and 25-50 l/ha – when aerial spraying.
To control the lodging of crops the treatment with the Tur preparation is carried out in the phase of bush emergence – the beginning of the tube at a dose of 3-4 kg/ha a.s. For example, the treatment of winter wheat crops of Mironovskaya 808 variety with Tur at the Experimental Field Station of the Moscow Agricultural Academy increased the yield by 0.25-0.8 t/ha.
Diseases of winter wheat include brown, yellow and linear rusts, dusty and durum buntings, root rot; pests include cereal (Hessian and Swedish) flies, the turtle bug, and the bread beetle. To control diseases and pests are effective:
- introduction of resistant varieties;
- against rust – treatment of crops with bilston at a dose of 0.5-1 kg/ha or zineb 3-4 kg/ha in the tillering phase – exit into the tube;
- against the bug-turtle, grain beetle, crops are sprayed with chlorophos 0.75-2 kg/ha or metaphos 0.5-1 kg/ha or volatone 2 kg/ha. During the growing season, 2-3 treatments are carried out, the last – no later than 15 days before harvesting.
The last treatment with any preparation should be carried out no later than 20 days before harvesting.
Harvest
When the grain reaches a pasty state, regular observations of the state of plants in the field begin. Ripening time is determined by many factors. So, in hot and dry weather on sandy and sandy loamy soils, on the southern, southeastern and southwestern slopes, ripening occurs earlier. For prompt decision-making on harvesting, 50-100 plants are selected daily in different parts of the field, which are threshed and analyzed.
The start date of harvesting is determined taking into account moisture, external signs and grain consistency, ear staining with eosin. The most objective indicator of grain ripeness is moisture content. Wax ripeness of grain occurs at a moisture content of 35-40%, while the optimal period for the start of two-phase harvesting is considered to be a decrease in moisture content from 35 to 20%.
The analysis takes into account the external signs and consistency of the grain. At the beginning of waxy ripeness, it turns yellow, resembles wax, is easily cut with a fingernail, but does not crush. At this time, all plants in the field become yellow, the green color is partially preserved only at the upper nodes of the stems.
Grain ripeness can be determined using eosin.
To make a decision to start harvesting, at least 70-75% of the total amount of grain should be in the ripeness phase. The ability of grain to ripen in windrows as a result of the recycling of plastic substances of stems, leaves and ears is an advantage of two-phase harvesting.
For high-quality harvesting, it is necessary to ensure modern organization of labor, stable productivity of equipment and the availability of qualified specialists.
Winter wheat harvesting accounts for 50-60% of the total cost of their cultivation. In the forest zone, this percentage is higher, in the steppe – less, which is explained by the complexity and laboriousness of the process. The delay in harvesting after the onset of full ripening leads to an increase in grain losses.
Biological yield – the amount of grain that was formed by the crop in the phase of wax ripeness before harvesting. It is determined on small sites (0.25 m2; 0.5 m2 or 1.0 m2).
Actual, or granary, harvest – the resulting harvest of grain after harvesting is completed. The maximum biological yield of high quality is formed in the middle and at the end of wax ripeness with a grain moisture content of 35-20%. During this period, separate harvesting begins, the duration of which should be 5-7 days.
These indicators are also stored in the phase of full ripeness at a humidity of 20-15% for 5-6 days after the onset. During this period, direct combining should be completed. Premature or late harvesting leads to a decrease in the size and quality of the crop. In this regard, 2-3 days before the start of harvesting, a control threshing is carried out. After that, mowing of fields is carried out at 25-30 m from the edge, with simultaneous breaking up of paddocks.
2-3 days before the main harvest, plant samples are taken along the diagonals of the fields and analyzed for uniformity in the quality of a batch of grain in order to prevent their mixing at the current. To do this, take grain samples of 1-2 kg from selected sheaves or control threshing.
Russian combines, such as Don-1500B; Yenisei-1200; Cedar-1200; Don-091; Don-161; SK-10V “Rotor”; Don-2600; PN-100 “Prostor”, have a fully mechanized grain harvesting process (mowing, threshing, cleaning, digging or chopping and spreading straw). However, on high-yielding fields, their use is associated with large losses. Foreign combines have a number of advantages.
In the steppe and forest-steppe zones, the largest grain harvest is achieved by two-phase harvesting in the middle and at the end of wax ripeness, when the maximum biological yield is formed, but the grain is still kept in the ear. This period is the best harvesting period, but its duration is 2-3 days.
It is impossible to clean all the areas in such a short time. If two-phase harvesting is carried out at the beginning of wax ripeness, then the yield is somewhat reduced due to the fact that the reutilization of nutrients from the vegetative organs for grain formation has not been completed.
Single-phase harvesting in the first 3-5 days of full grain ripeness does not lead to large losses. Late harvesting in this way, that is, 10-15 days after the optimal period, can lead to losses of up to 20-30% of the grain. Therefore, in the presence of large areas of grain crops, harvesting begins in a two-phase method at the beginning of wax ripeness and continues until the end of the phase. Upon reaching full ripeness, they switch to a single-phase method. Under favorable weather conditions, due to the greater productivity of the two-phase method, it is possible to remove the main areas before full ripeness. The remaining smaller part of the area can be harvested at the optimum time.
This method is used for low-growing, sparse and over-aged cereals, short-stemmed varieties that are resistant to lodging, as well as in areas with high humidity during the harvesting period. The cutting height is set for low-growing and lodged crops – no more than 10 cm; for long-straw and decumbent – 15-20 cm.
Two-phase harvesting is used for high-stemmed, unevenly ripened and prone to lodging and shedding varieties, as well as for weedy crops. Stem density should be at least 250-300 plants per 1 m2. The cut height is set at 12-25 cm. In areas with high humidity, thin wide swaths are formed, in dry ones – narrow thick ones. Mowing is carried out across the rows for better stacking of stems in rolls. Two-phase harvesting is especially important in areas with a long period of grain ripening and a short harvesting period.
Despite the advantages of two-phase harvesting, it should be rationally combined with single-phase harvesting. So, in case of bad weather during the harvesting period, direct combining is preferable, since under these conditions, ears on the vine dry out faster than in windrows.
During two-phase harvesting, winter wheat is mowed with reapers, for example, ЖВН-6А, ЖВР-10, ЖНС-6-12, ЖНУ-4,0, ЖСБ-4,2, and placed in rolls on the stubble. With a stubble height of 15-20 cm, optimal conditions are created for windrow blowing. For tall loaves, the stubble height can reach up to 18-22 cm, for thicker ones – 12-15 cm. Rolls should not touch the ground. The width of the rolls should be up to 1.6-1.7 m; thickness in the south of the country – up to 25 cm, in humid conditions – up to 15-18 cm.
Stems in rolls should be located at an angle of 10-30 ° to the longitudinal axis. In some regions of Russia, the duration of drying rolls is different: for the North Caucasus and the Southern Volga region – 2-3 days, in the Central Black Earth zone and the Middle Volga region – 3-4 days, in the Non-Chernozem zone and the Urals – 5-7 days.
In rainy and cloudy weather during harvesting, the drying time will increase by 2-3 days. It is impossible to leave cereals in rolls for a long period, as the yield and quality are reduced. The rolls are dried to a grain moisture content of 18-16%, as it continues to decrease later during threshing, transportation and reloading. Strongly overdried grain can be damaged during threshing.
Under favorable weather conditions during harvesting, and if the crops are not lodged, then the loss of grain behind the reaper, during selection and threshing is minimal. Crushing of seed grain is allowed no more than 1%, food and feed – no more than 2%.
The performance of reapers is 2 times higher than that of combines that work in a single-phase way. However, the productivity of combines when threshing windrows is 25-30% higher than direct combining.
The use of single-phase and two-phase harvesting methods, as well as specific details of harvesting work, require a qualified approach with sufficient practical experience. The optimal combination of them is found in each specific of farms and under various weather conditions. Thus, it is impossible to use two-phase harvesting on undersized, sparse and low-productive crops. It is necessary to apply this method with caution in rainy weather, on tall crops, since the rolls will not dry out. At the same time, two-phase harvesting is used in heavily weedy fields.
Straw and chaff should be removed immediately after threshing, which allows you to quickly free up the field for subsequent work. Depending on the natural and climatic conditions and the possibilities of the farm, straw is harvested in loose or pressed form. Due to the reduction in the use of organic and mineral fertilizers, part of the straw when harvesting grain crops is used in crushed form as an organic fertilizer.
Straw and floor should be removed immediately after threshing, which allows you to quickly free up the field for subsequent work. Depending on the natural and climatic conditions and the possibilities of the farm, straw is harvested in loose or pressed form. Due to the reduction in the use of organic and mineral fertilizers, part of the straw when harvesting cereal crops is used in crushed form as an organic fertilizer.
When harvesting winter wheat, as well as other cereal crops, harvesting and transport complexes are used, including links:
- preparation of fields for harvesting – mowing and swathing in areas, preparation of turning lanes;
- combine-transport – mowing, picking up and threshing windrows or direct combining, collecting and transporting grain, chopped straw and chaff to storage sites;
- for maintenance – ensuring the readiness of equipment;
- for harvesting the non-grain part of the crop – straw piling and stacking, straw pressing from rolls and its transportation;
- for primary tillage – discing and plowing of cleared fields.
Cultivation under irrigation
The cultivation of winter wheat under irrigation conditions significantly increases the gross grain harvest. For example, the Rostov Experimental Ameliorative Station on irrigated lands receives 6.0 t/ha of grain. In Kabardino-Balkaria, on irrigated lands, the average yield over a number of years reaches 4.28 t/ha, without irrigation – 0.52 t/ha. Modern varieties under irrigation conditions are capable of yielding up to 8 t/ha. Such results were obtained at the All-Russian Research Institute of Irrigated Agriculture. However, the average yield under these conditions remains about 4 t/ha.
In the conditions of the South-East, the steppe regions of the North Caucasus and in the south-east of Ukraine, one of the tasks of the winter wheat crop is to obtain uniform seedlings and its good development in autumn. For the successful development of winter wheat, it has pre-sowing (moisture-charging) irrigation. Soil moisture charging during the non-vegetation period at a water consumption rate of 800-1500 m3/ha ensures high yields.
At the Stavropol breeding and experimental station, on average for 6 years, the yield of winter wheat after water-charging irrigation was 4.67 t/ha, without irrigation – 2.49 t/ha.
The greatest effect of pre-sowing irrigation is achieved in years with dry autumn and wet spring of the next year. On the contrary, during wet autumn and dry spring, irrigation during the growing season is more effective than pre-sowing.
Moisture-charging irrigation can be carried out before or after plowing. Pre-arable watering accelerates the germination of weed seeds and promotes their growth. Sprouted weeds are destroyed by subsequent deep plowing. This method increases the irrigation period, thereby reducing the tension in the work and using channels and structures more efficiently.
Moisture-charging irrigation starts a few weeks before sowing and ends at such a time that there is enough time for pre-sowing tillage and sowing at the optimum time. Despite the great importance, irrigation can only produce average yields of winter wheat. The best results are obtained by a combination of water-charging and vegetative irrigations.
At the Grozny experimental reclamation station, the average yield of winter wheat over 4 years was: without irrigation 1.02 t/ha, with water recharge irrigation – 2.16 t/ha, with water recharge irrigation and two vegetation irrigations – 3.46 t/ha , with 2-3 vegetative irrigations – 2.55 t/ha.
Irrigation methods
In practice, surface irrigation and sprinkling are used. Surface irrigation is subdivided into furrow irrigation and strip irrigation. When irrigating along the furrows, the soil is moistened through the bottom and walls of the furrows due to infiltration, which makes it possible to achieve uniform moisture and more economical water consumption. In addition, a crust does not form near the plants, the evaporation of moisture from the soil decreases.
Irrigated sown furrows are made simultaneously with sowing, for which the seeder is equipped with furrow makers. The distance between irrigation furrows is determined by the water permeability of the soil: on light furrows, irrigation furrows are arranged at a distance of 50-60 cm, on medium ones – 60-80 cm, on heavy ones – 70-90 cm. The direction of the furrows is done taking into account the mechanization of field work in irrigated areas.
Compared to furrow irrigation, sprinkler irrigation has many advantages. It can be used on almost all soils and any terrain. Water is distributed evenly over the entire surface of the field. Sprinkling does not require cutting channels, irrigation furrows, the land is used more efficiently. Sprinkling saves more than 60% of water compared to furrow irrigation, soils are not saline.
Irrigation times and rates
When determining the timing and number of irrigations of winter wheat, they proceed from the reserves of moisture available to plants in the soil. The first vegetation watering, as a rule, is carried out at the beginning of the plant’s emergence into the tube, about a month after the start of spring regrowth. Subsequent terms and rates of irrigation are determined based on soil moisture and the characteristics of the year.
Watering rates may vary: on heavy soils and with a slight slope, the watering rate is higher; on the lungs and with a large slope, the irrigation rate decreases. Norms also depend on the method of watering.
For an average year in terms of moisture, the approximate norm for each vegetation irrigation along the furrows is 600-700 m3/ha, when irrigated by strip irrigation – 700-800 m3/ha, when sprinkling – 450-500 m3/ha.
In years with a dry autumn, water-charging irrigation is carried out after harvesting the previous crop. Taking into account the initial humidity, the consumption rate is from 600 to 1500 m3/ha. Excessive autumn irrigation can lead to a delay in the development of plants and adversely affect overwintering.
The number of summer waterings, as a rule, is two: in the earing phase and at the beginning of grain filling. Vegetative irrigation is carried out with a decrease in soil moisture to 70-80% of the lowest moisture capacity in the calculation of 500-800 m3/ha.
Fertilizer
Fertilizers under irrigation conditions give a good effect. A stable increase in the yield of winter wheat grain from mineral fertilizers during irrigation is 1.0-1.4 t/ha.
The rate of fertilizer application is calculated taking into account the fertility of the soil and the planned yield.
About 60-80% of phosphate and 80-100% of potash fertilizers are applied under plowing; for presowing cultivation – about 25% nitrogen; 20% phosphorus – when sowing in rows.
During early spring top dressing, 60-75% nitrogen is applied, during the period of going into the tube – earing, 15% nitrogen, 20% phosphorus and potassium are used, taking into account the diagnosis of plant nutrition. The last (summer) nitrogen foliar top dressing improves the quality of grain and straw, gives it strength and resistance to leaf rust. For foliar top dressing, mineral fertilizers are dissolved in 250-300 liters of water per 1 ha and applied by ground sprayers or by aircraft.
Tillage
The tillage system on irrigated lands is mainly aimed at combating weeds, which grow much faster under these conditions. The depth of the main plowing is 25-27 cm. As weeds grow, they are destroyed by cultivation.
Sowing
For sowing, zoned intensive varieties are used, adapted to high soil moisture and surface air, responsive to a high agrotechnical background, resistant to lodging. For example, varieties Bezostaya 1, Odessa 51, Donskaya semi-dwarf, Parus.
Sowing is carried out at the optimal time in a narrow-row or cross-row methods. If vegetative irrigation is planned, then during sowing irrigation furrows are made or irrigation strips are cut so that the rollers and furrows are covered with wheat shoots. Sowing is carried out with a seeder coupled with a roller-maker. The direction of travel of the seeder and roller maker must correspond to the slope of the terrain. The seeding rate under irrigation increases by 10-15%, the seeds are planted to a depth of 6-8 cm. In this case, the tillering node is located deeper, and the wheat acquires increased resistance to lodging and freezing.
Crop care and harvesting
Care of crops consists in snow retention techniques to protect against freezing, top dressing and harrowing in early spring. Spring harrowing on fields prepared for vegetation irrigation is carried out only along and inside the strips so as not to destroy the rollers. For harrowing and loosening, it is better to use rotating hoes.
To combat lodging, crops are treated with Tur or other growth regulators, short-stemmed varieties resistant to lodging are used, sowing is carried out at optimal times and seeding rates, moderate doses of mineral and organic fertilizers are applied, watering should be normalized taking into account soil moisture. In case of contamination of crops, herbicides are used.
Harvesting, usually two-phase.
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 agricultural production technology. Farming and plant growing. Ed. by V.S. Niklyaev. – Moscow: “Bylina”. 2000. – 555 с.