Calculation and determination of the optimal seed sowing rate winter wheat provides the best feeding area for all plants and guarantees productive operation of the photosynthetic apparatus.
For all soil and climatic zones (taking into account varietal characteristics), according to data from research stations and cultivar plots of originating institutions, approximate seeding rates are established in millions of similar seeds per hectare.
Organic matter is the food component of soil. Live fungi and bacteria work to break down organic matter. When these soil microorganisms eat organic matter, the nutrients are released back into the soil in a form usable by plants. This process is called the nutrient cycle. Nutrient cycling affects both physical and Chemical properties soil. Cover crops choke out weeds by limiting sunlight to the soil, stabilizing the soil surface and, through their deep-rooted roots, help break down soil and bring nutrients to the surface for use by other plants.
How to calculate the seeding rate of winter wheat
where N is the seeding rate, kg/ha;
K - million seeds per 1 ha;
B - mass of 1000 seeds, g
G - sowing or economic suitability,%;
A - seed purity,%;
B - seed germination,%.
The use of this formula shows that the seeding rate of winter wheat depends on the seeding coefficient (K), the weight of 1000 seeds (B) and sowing suitability (G). Other factors are not taken into account. Provided field germination is obtained at the laboratory level and there is no plant death during the growing season, this formula would be very convenient for calculations.
However, if the pre-sowing preparation of soil and seeds is insufficient, field germination can exceed 70-80%. Calculation of the seeding rate of winter wheat using this formula takes this into account and provides for sowing safety stock seeds, which is about 20-30% of the seeding rate.
As part of a long-term rotation plan, cover crops can provide a sustainable habitat in your garden for beneficial insects and microorganisms. Green manures can be grown in the same year as vegetable crops, such as a clump of white clover planted around corn. They can be grown as perennials in gardens and vineyards. In temperate climates, seed crops can be planted and cultivated the following spring just before planting. In harsher climates, seed crops can be grown in rows between crops or as part of a rotation in your garden.
There have been many attempts to develop a formula to accurately determine seeding rates. Some of them are less successful, while others are more suitable and convenient for sowing rationing.
At first glance, the formula proposed by V.A. Vrzheshch deserves attention. It takes into account the volume of field germination and liquefaction from harrowing:
Green manures are an excellent source organic matter when they are cut and turned over. Apart from this benefit, legume green manures act as a host for bacteria that fix and make nitrogen available to your vegetable or fruit crops. Cereals legumes are an important component good management soil. Growing legumes and incorporating them into the soil increases organic carbon and improves soil fertility and the soil's water retention capacity.
where P is field germination,%;
C - liquefaction from harrowing,%.
One disadvantage is that the formula for sowing seeds of winter wheat does not take into account the part of the plants that falls during the growing season. However, its main mistake is that the addition with 100 / P-S duplicates the very formula H = K B 100 / G, which is precisely designed for the existing level of field germination and plant survival. The result of applying this formula will be an unreasonable increase in the seeding rate:
To maximize nitrogen output, legumes should be incorporated into the soil at peak flowering. Grains and Grasses Grains and grasses grow very quickly and provide rapid ground cover. They can provide huge amounts of biomass, which not only keeps weeds at bay and prevents soil erosion, but also transfers huge amounts of green matter or green manure back into the soil, which improves soil thickness. large processors of nutrients. The plant's uniform root system pulls nitrogen and other minerals from deep in the soil and stores these elements in its roots and leaf structure.
As you can see, the difference is 73 kg/ha.
A completely different approach to calculating the seeding rate of winter wheat was used in the formulas presented below. Here, the basis is not the number of seeds sown per hectare, but the predicted density of productive stems and the tillering coefficient, which, in our opinion, are more realistic factors.
This is a formula developed by M.S. Khomenko and co-authors: 
When turning to a crop, nitrogen and other elements are released or returned back below the soil surface, so the next crop can use nitrogen that was once unavailable and leached. Growing grains as a crop provides other opportunities such as animal feed or human food. We strive to offer varieties that give gardeners flexibility in how the best way use the crop: for food, feed or green manure.
A great culture that works in three ways. When sown in the fall, it grows quickly and overtakes the weeds, and then, when the cold days of winter begin, it goes dormant. The arrival of spring brings growth that can be turned under green manure. If left to grow, winter wheat makes good livestock feed; or if allowed to ripen, it can be harvested in midsummer. Winter wheat is an exceptional, inexpensive and fast-growing cover crop that suppresses weeds and diseases with its allelopathic effect.
where Nm is the seeding rate, million seeds/ha;
Y - planned yield, c/ha;
X - coefficient of productive tillering;
a - plant survival: an indicator of the ratio of the number of plants that survived harvesting to the number of sown viable seeds,%;
b - expected number of grains in an ear, pcs.;
in - expected average weight 1000 grains, g.
The seeding rate in kilograms per hectare is determined by the formula,%: 
Fast growing brass provides a thick ground cover that protects the soil from erosion and helps suppress weeds with dense amounts of biomass. Some bras have a large root that can push through plows or rotary pots, thus aerating the soil. Roots also remove nutrients from deep in the soil and return them to the surface, where they can be used in subsequent plantings to harvest food crops.
And if you leave the flower, Brazilians are especially popular with beneficial insects. Annual biennial perennial. Canola is ideal, but problems arise with later ripening varieties. Some producers are looking at earlier planting stages such as peas, but the snow trap index as a proxy for snow isolation for pulses is low, so this has prompted more research into pulses as well as barley silage stubble, says Brian Beres, research scientist Agriculture and Agri-Food Canada in Lethbridge, Alta.
Analysis of the components of the third formula for sowing winter wheat shows that much more informative indicators are taken into account here. However, the use of this formula also revealed some of its shortcomings. An increase in the planned yield, even if other indicators remain unchanged, causes an increase in the seeding rate. This relationship is illogical, since the same level of yield can be obtained with both low and high seeding rates. It all depends on the method of forming the required density of productive stems: either by increasing the seeding rate and creating single-stemmed plants, or by intensifying tillering in order to form multi-stemmed plants.
The four-year trial was staged in Lacombe in Alberta, Melfort and Indian Chief in Saskatchewan, and Brandon in Manitoba. In the first year, six crops were grown, including barley for grain harvest, barley for silage, rapeseed, peas, cereals, red spring wheat and rapeseed. After harvest, two varieties of winter wheat, hard red spring wheat, Canada amber wheat and barley, were grown on the stubble. Winter wheat was planted at the optimal date immediately after harvest, and spring crops were planted by May 15 the following spring.
In turn, thickening of crops due to an increase in the seeding rate of winter wheat will not leave unchanged the indicators that are placed in the denominator of this formula. Due to the reduction in the living space of each individual plant, it is necessary to predict a decrease in field germination, tillering coefficient, plant survival, number of grains and weight of 1000 seeds. Taking into account these amendments, the seeding rate of winter wheat increases even more and it becomes impossible to use this formula for calculations. Thus, with a yield of 60 c/ha, the seeding rate is 142.4 kg/ha, and at 80 c/ha and a decrease in plant thickening indices of their field germination, tillering coefficient, plant survival and number of grains increases to a fantastic size: 525. 2 kg per hectare.
Overall, Beres says winter wheat baits were adequate throughout the study period, although slightly below optimal. He says yields for winter wheat grown on canola, barley for silage and peas were often the highest, while yields for wheat, oats and barley for grain were often the lowest. Beres reports that the results reinforce the idea that stubble types other than canola may be good choice for winter wheat producers to ensure optimal winter wheat yield and kernel quality.
In our opinion, the formula for calculating the sowing rate of winter wheat seeds, proposed by Professor M.S. Savitsky, is closest to the requirements of intensive technology:
where C is the optimal number of productive stems per 1 m2 before harvesting, pcs.;
D - plant survival: an indicator of the ratio of the number of plants that survived harvesting to the number of sown viable seeds,%.
“Winter wheat planted on barley silage stubble is really good, but if you grow it on barley stubble harvested for grain, it's not so good,” Beres says. I think this is probably due to competition from volunteers left behind after the grain harvest. Volunteer barley is very competitive, even against winter wheat, and is difficult to clear with herbicides. There are a few options, but if you don't barley volunteer soon enough, it's a serious drain on income.
The results also showed that the typical pulse rotation effect that usually occurs with spring crops was not evident. Leaf disease was measured on the penultimate leaves of winter wheat at one location over three years. Disease severity on barley stubble may be greater because winter wheat had better plant stand, more favorable for disease development, than barley for grain stubble.
This formula for sowing winter wheat contains all the main indicators, the optimality of which determines the volume of the harvest. However, unfortunately, the sowing suitability of seeds is not taken into account here, and indicators such as field germination and plant survival during certain periods of growth are not differentiated. This is very important for intensive technologies, when it is possible to regulate the processes of formation of individual elements of productivity at different phases of growth.
The formula proposed by M.E. does not solve the problem of accurate calculation either. Nikolaev:
Beres also warns growers that they are not providing a green bridge for wheat mosaic virus to move from spring seed volunteer cereals to winter wheat seedlings. Barley silage can regenerate in the fall to provide a green bridge, and barley volunteers can also germinate and grow in the fall even on silage bristle, which can also provide a green bridge.
Be aware of the green bridge. Pre-burning, which eliminates all green material before planting the winter wheat crop, is very important, says Beres. The results of this study suggest that seeding winter wheat in barley silage and field peas is a good alternative, although rapeseed may be ideal. Beres says agronomic practices will be the same as when planting winter wheat on canola or peas.
where P is the number of plants to be harvested, million/ha.
This formula for sowing winter wheat includes an indicator of economic suitability that is not in the formula of M.S. Savitsky. However, instead of the number of stems and tillering coefficient, a simplified indicator is given, expressed only by the number of plants to be harvested, that is, this is a drawback of the calculation, which we considered in the first two formulas.
Field rules and regulations. Each hunter is responsible for not hunting for bait. So how does a hunter know if a particular area is legal to hunt? The key to determining whether a field is legal is to use good agricultural practices. If corn, milo, wheat or some other grain crop has been planted and harvested in the normal manner, it is perfectly legal to hunt. However, if cracked corn, wheat, or any other grain was poured onto the ground in large piles, it is not a fair agricultural practice and would be illegal profiteering.
Simple calculations show that if we take the number of plants as 200 pcs. / M2, then the seeding rate will be 159 kg / ha, and for 400 pcs. / M2 - already 319 kg / ha. Considering the decrease in plant survival (D) under the influence of thickening, the seeding rate will be even higher, which is unrealistic.
On the other hand, a planned 200 plants may have 200 productive stems at a tillering ratio equal to one, and 600 colossi for three shoots on a plant. In these two options, the seeding rates of winter wheat should be different, but the calculation will give the same result.
Every hunter should check the field before dove hunting. If the field has been recently recorded and has a high concentration of doves, check what type of grain is attracting doves. If there are cracks in corn, soybeans, sunflower seeds or other grains, and no evidence that these grains are simply typical remains from harvesting the crop that was grown there, it is best to walk away. If the grain is present along with the seed stubble, making it obvious that the crop was harvested from that field, it is legal.
Wheat is planted this time of year in Tennessee as a standard agricultural practice, so if a hunter checks a field that has been cut and planted with wheat, it may be legal. But wheat must be evenly distributed, not planted more than once in one area, and cannot exceed the normal planting rate. If the wheat is in piles or deep strips, it is illegal. If there is an excessive amount of wheat, although it is evenly distributed, it is illegal.
The presence of the C/X ratio in formula (4) makes it possible to regulate the seeding rate depending on the density of the productive stem and the tillering coefficient, which is impossible using formula (5). That is, the formula M.E. Nikolaeva is also not flawless, somewhat “artificial” and is the worst version of the M.S. formula. Savitsky.
The formula we developed takes into account the indicated disadvantages of the previous ones. It is clear that it is impossible to foresee all the complex processes that occur in a plant agrobiocenosis. However, it makes it possible to establish the actual seeding rate: 
where C is the death of winter crops during the wintering period,%;
M - grain mass per ear, g
d - death during the spring-summer growing season,%.
One thing a hunter needs to ask himself is how well do he know the landowner? Does he always follow the rules of the wild? While the federal law permits the manipulation of the cultivation of grain crops specifically for the purpose of attracting pigeons for hunting, sowing any grain immediately before or during the hunting season for the purpose of attracting pigeons is considered baiting and is illegal to hunt pigeons. Assuming it is legal to grow winter grains in the fall to ripen and manipulate them for dove hunting during the following year's hunting season.
The formula takes into account the density of the productive stem stand (C): the higher it is, the greater the seeding rate should be. An increase in the tillering coefficient (X) and grain weight per ear (M), on the contrary, contributes to a decrease in the calculated seeding rate. The formula also includes indicators of the weight of 1000 seeds (B) and economic suitability (D). Sowing with large seeds reduces the economic suitability indicator, but provides for an increase in the seeding rate. The plant survival rate, which is understood as the ratio of the number of plants preserved and the number of sown viable seeds, is differentiated into three components: field germination (P), loss of plants during the winter (s) and loss of plants during the spring-summer growing season (d). With intensive technology, these indicators are optimal, which helps to reduce the seeding rate. Thus, the relationship between all components of the formula can be traced; it covers almost all the main elements of the structure of the expected harvest, on which the seeding rate depends.
Should wheat be sown on prepared land? Winter wheat often does not try to drill into unprepared soil. Additionally, top-seeding winter grains in certain non-farm agricultural products, such as soil erosion control and replanting wheat or rye prior to harvesting soybeans, corn, or cotton to create a crop, are recognized as common agricultural practices in Tennessee.
However, only for these specific situations listed above would it be legal to hunt doves over winter grain sown on unprepared ground. It is an unfair agricultural practice to sow grain several times in a row. In the absence of drought or flooding, planting should be carried out only once in a seeding area prepared to sufficiently support germination. Once a corn field is harvested and the entire field or strips are plowed and planted in wheat, is it considered a legal dove hunting field?
Calculations of seeding rates using formulas (4) and (6) give similar results, but the latter formula is more differentiated about the features of the technology and is flexible in application: 
For an objective comparison: in all formulas the indicators were taken to be the same. If we substitute the values obtained in our experiments on the development of resource-saving technology, the seeding rate will change towards a decrease:
In our experiments to study seeding rates of winter wheat, where options with 2.0 were studied; 3.0; 4.0 5.0 million seeds/ha, the highest yield was in sowing 3.0 million seeds/ha, which for a mass of 1000 seeds of 45 g is 135 kg/ha. That is, the optimal hanging rate, established experimentally and calculated using the formula, is almost the same. And this is the main and most important confirmation of the correctness of the formula we propose.
Calculations of seeding rates for seed and winter wheat show that this formula is universal in nature and gives real numbers even with a significant decrease in field germination and tillering:
V. Likhochvor, Doctor of Agricultural Sciences Sciences, Professor, Head of the Department of Technologies in Plant Growing, Lviv National Agrarian University
Much attention is paid to the selection of the best predecessor for winter wheat. Some researchers in their works prefer pure steam.
It is impossible to say unequivocally that pure steam has only advantages; it has both positive qualities and disadvantages. Black steam is associated with improving the phytosanitary situation, reducing the intensity of field work during periods of maximum load, increasing the sustainability of grain production and its quality, and is a powerful means of combating drought. The disadvantages are the absence of any agricultural products during the spring-summer period of fallowing the field, excessive mineralization of soil organic matter and increased erosion danger; there is a significant increase in unproductive moisture losses. The best non-steam predecessors are peas and cereal legume mixture.
Under winter wheat and peas, the nutritional regime of the soil was different - nitrate nitrogen before sowing winter wheat over peas was slightly less than after pure fallow, which made it possible to obtain on average up to 5.0 t/ha of winter wheat grain. However, if we take into account that the area under fallow for one year does not participate in production, and the relatively high yield of the fallow field is the result of two years of work, then the average yield of a particular field is 2.3-2.5 t/ha.
The importance of peas in the structure of the feed ration can hardly be overestimated. The short growing season and the accumulation of nitrogen in the soil up to 30 mg/kg of soil make peas a good predecessor. The yield of winter wheat after peas is somewhat inferior to that of pure fallow in the range of 0.5-0.7 tons and amounts to 3.9-4.5 t/ha depending on the year. But in terms of technological and baking qualities, winter wheat grain grown after peas is no different from grain obtained by steaming. At the same time, the yield over two years in the peas-winter wheat link reaches an average of 3.0-3.5 t/ha, which is 0.7-1.2 tons higher compared to the pure fallow-winter wheat link. A large number of researchers note the entry into the soil of a large amount of stubble and root residues after legumes.
The issue of selecting predecessors for winter wheat should be decided taking into account the characteristics of the variety. Thus, semi-dwarf varieties of the intensive type Donskaya Yubileinyaya, Donshchina, Zernogradka 8, Zernogradka 9 and others should be placed primarily in black pairs, and taller varieties of the semi-intensive type Don 93, Don 95, Ermak, Kolos Dona, Dar Zernograda, Donskoy Mayak and others - based on non-steam predecessors. It should be noted that the hard turgid winter wheat varieties Novinka 4, Donchanka, Zhemchuzhina Dona and Donskoy Yantar need to be sown only in black pairs.
The organic mass of peas during decomposition ensures an increase in humus reserves due to the large yield of humic substances.
As M.I. rightly notes. Sidorov et al., successful cultivation of plants in agrocenoses is possible only in crop rotation based on fruit rotation, when crops with high and low nitrogen content and biomass (peas - winter crops) alternate, improving the nitrogen nutrition of plants, promoting a more rational consumption of humus. By increasing the biological activity of the soil and its phytosanitary condition, legumes generally have a beneficial effect on soil fertility.
An important feature of the initial growing season of winter wheat is that at this stage it is necessary to optimize such a factor as biological time. Its optimization consists in using a set of technological measures to ensure that in the autumn the plants pass through those stages of organogenesis, on which the level of viability of the agrobiocenosis and its productivity subsequently significantly depend. One of the most important technological measures is the correct choice of sowing time.
Academician P.P. Lukyanenko argued: “None of the agricultural techniques has such a profound effect on the growth and development of a winter plant as the sowing time and seeding rate.” Many researchers paid attention to this issue, for example, A.I. Nosatovsky, N.N. Borodin and others. Right choice The timing of sowing is related to agrometeorological conditions like no other method of agricultural technology.
The damage to winter wheat plants by many pests and diseases largely depends on the timing of sowing and seeding rates. On winter wheat early dates sowing, as well as thickened ones, create favorable conditions for latent pests. In addition, in this case, biological outgrowth of plants occurs and they go into winter weakened. The timing of sowing winter wheat in each specific case should be set depending on the temperature regime, predecessors, availability of soil moisture and varietal characteristics. It is necessary to start sowing winter wheat at an average daily air temperature of +14...+17°C, which, according to average long-term data, determines the optimal sowing time for various zones of the region.
In fallow fields, where soil moisture guarantees timely germination (at least 10 mm of productive moisture for every 10 cm of soil), winter wheat should be sown only at the optimal time, determined by the temperature factor.
After non-fallow predecessors, the sowing time must be directly dependent not only on temperature, but also, most importantly, on the moisture reserves in the soil. If the soil is well moistened to a depth of 15-18 cm, you can start sowing 5-7 days earlier than the optimal time. If the soil is dry or semi-moist, then you should not sow even when the optimal time has arrived. In this case, sowing should be postponed to a later time, when precipitation may occur and the temperature will drop to 10-12°C, which prevents molding of the seeds.
The timing of sowing has a great influence on the quality and size of the harvest. The conditions for plant growth and development, resistance to adverse meteorological phenomena, and harvesting conditions are inextricably linked with them. A lot of work is devoted to studying the influence of different sowing dates on winter crops during the autumn growing season and, in connection with this, the influence of plant development on their overwintering. These works established that both too early and too late dates sowing negatively affects overwintering and the harvest of winter crops. The timing of sowing also affects the effectiveness of other agrotechnical measures: the fight against weeds, pests and diseases, and the effectiveness of fertilizers. By choosing certain sowing dates, there is a certain opportunity to place plants in conditions of varying lengths of daylight hours, temperature and humidity of air and soil. The optimal sowing time is determined by the biological characteristics of the cultivated crops, their varieties and agrometeorological conditions. For spring crops great importance has the temperature of seed germination and the ability of seedlings to withstand possible spring frosts. The time for sowing winter crops is set in such a way that the plants will bloom well before the onset of winter and become hardened to low temperatures. Much attention is paid to sowing dates due to the fact that their deviation from the optimal entails significant losses in the yield and gross grain harvest of winter wheat.
L.B. In his research, the fisherman came to the conclusion that those winter wheat plants that are sown at the optimal time are the most resistant to lodging. In late-season crops, the number of adjustments during tillering in the spring increased, which reduced their stability. The closest thing to reflecting the real dependence is the statement of S.F. Tikhvinsky and L.K. Butorina that the timing of sowing winter grains directly affects the overwintering of plants, and indirectly affects the resistance to lodging: well-overwintered thick grains lay down more often and to a greater extent.
I.V. Svisyuk writes that establishing the sowing date based on non-fallow predecessors in a dry autumn, with the accumulation of effective precipitation values close to 5 mm, is a responsible matter, since if these values are not taken into account, then gross miscalculations and large thinning of crops over large areas can be made . When effective precipitation accumulates less than 5 mm at the beginning of the optimal sowing time, then it is better to postpone the sowing of winter crops to a later date, when precipitation can ensure seed germination and further development plants. If this is not done, then in a particularly dry autumn the seeds lie in the soil for a month or more without germinating. Over such a long period, they partially or completely die, causing thinning of the crops. Seed death occurs for the following reason. Seeds are located in the soil at different depths (no matter how well the sowing is done). Relatively light precipitation, which is not able to wet the soil to the depth of mass planting of seeds, for a short time creates a wet bed for seeds located in the surface layers. Once in a zone of such moisture, they begin to swell, often peck and even germinate. But the moisture in the upper layer of soil at high temperatures is completely lost after a short time. A.I. Nosatovsky pointed out that at a temperature of +24° and the soil of the seed is moistened to 30-45% of its total moisture capacity, the grain stops absorbing moisture after two days, and after three days it loses what it absorbed in the first day. The development process is suspended, but such a seed still remains alive. With new moisture, it begins to germinate and is capable of producing a plant, but it grows weak and produces a reduced yield. Naturally, if such a phenomenon is repeated more than once, then the seed dies.
IN AND. Bondarenko et al., studying the productivity of winter wheat crops of different sowing dates at the Erastov Experimental Station of Ukraine, found that early sowing crops, especially those with non-fallow predecessors, had the lowest field germination, frost and winter hardiness, and were inferior in yield to crops of other dates. Of the varieties studied (Bezostaya 1, Odesskaya 51, Dnepropetrovskaya 846 and Odesskaya semi-dwarf), the Odesskaya 51 variety turned out to be the most flexible, the yield of which depends less than others on the sowing time.
One of the reasons for the strong dependence of yield losses when sowing dates deviate from the optimal one is the different winter hardiness of plants of different ages. High winter hardiness is possessed by those stems that, by the time the growing season ceased, had passed the vernalization stage and did not have time to grow old. Such stems are formed 22-42 days before the end of the growing season. Therefore, very early and too late sowing disrupts this vernalization process and, as a result, adversely affects winter hardiness and yield.
Thus, the maximum yield of winter wheat is obtained when sowing at or close to the optimal time. In this regard, the question arises as to how far these terms can be extended so as not to cause a significant reduction in the yield. I.V. Svisyuk proposed to take as the optimal range of sowing dates such a deviation from the optimum, within which the relative decrease in yield does not exceed 5%.
The optimal timing of sowing winter wheat significantly depends on soil and climatic conditions, biological characteristics of the variety (its frost resistance, depth of winter dormancy, duration of vernalization) and the supply of mineral nutrition elements to plants. It is very difficult to describe the influence of all these factors with a general model. Therefore, the issue of optimizing sowing dates is resolved by establishing empirical dependencies that take into account the diversity of conditions in the autumn and winter periods.
The methods for calculating the optimal sowing time are based on the features of the tillering process and the duration of the sowing-tillering period. The most viable plants are those that, by the time the growing season ends, have blossomed and have 3-6 shoots. Consequently, the timing of sowing should ensure in the fall the necessary vegetative mass of plants and such a degree of tillering development that ensures good overwintering and entry into the generative phase in the spring as early as possible.
I.G. Yulushev draws attention to the fact that the order of sowing fields with winter grains must be established depending on the amount and composition of the fertilizers used and the nature of the previous crop. First of all, you should sow the fields where the least fertilizers were used, where there are the least nutrients in the soil. Here, the periods of plant growth and development will be extended due to a weak supply of nutrients; with late sowings, they will go into winter underdeveloped. At the same time, occupied fallows and fields where non-fallow predecessors were cultivated should be sown. The decomposition of fresh plant residues is slow; with a lack of fertilizers, the supply of nutrients to plants can be very modest. The fields where the most nitrogen is likely to be in the soil should be seeded last. These are fields fertilized with manure, composts, and high-yielding grasses after legumes. Excess nitrogen can lead to the violent development of vegetative mass in the fall, and this is a springboard for pests, snow mold. Such plants suffer most from damping off, bulging, freeze faster,
From 1981 to 2005, in the “System for maintaining the agro-industrial complex of the Rostov region...”, and starting from 2006 - in the “Zonal systems of agriculture of the Rostov region on a landscape basis”, in the Azov and southern zones of the Rostov region it was envisaged to have up to 12 .5-13.6% of net vapors from the area of arable land. Basically, these recommendations are followed.
Rational placement of plants in sowing is one of the most important and oldest issues in agriculture. It contains several aspects: biological (potential productivity of varieties, early ripening, bushiness, resistance to lodging, etc.), agrotechnical (fertilizer application, precursors, timing and methods of sowing, etc.), natural (natural soil fertility, physico-chemical soil properties, location of the field according to the relief, etc.), economic (weed infestation of fields, purpose of crops - for grain, for grain with undersowing of grass, for seeds, for green mass, quality of seeds, etc.), agrometeorological (security light, heat and moisture during growing season in accordance with the changing needs of plants during ontogenesis).
A huge amount of experimental material has made it possible to establish optimal average sowing rates for agricultural crops both for large natural areas of the country and for individual regions and experimental stations. The agronomic literature contains recommendations for some differentiation of these average norms depending on soil fertility, varietal characteristics of the crop, predecessors, purpose of crops, timing and methods of sowing, weediness of fields, relief conditions, etc. Crops are a self-regulating plastic system that strives to form the optimal structure of assimilative and reproductive organs under given conditions and, ultimately, maximum yield.
When establishing seeding rates for winter wheat, it is necessary to take into account soil fertility, predecessors, meteorological conditions, sowing dates, sowing methods and other conditions. A correctly established seed sowing rate will contribute to better use nutrients and moisture from the soil, on which the winter wheat harvest depends. Thinned and thickened stems reduce the yield.
The study of seeding rates for agricultural crops has a long history. Such prominent scientists as D.N. made a great contribution to the study of this issue. Pryanishnikov, F.M. Prutskov, M.S. Savitsky, P.P. Lukyanenko, V.N. Craft, G.V. Korenev, V.A. Alabushev, N. A. Zelensky, N.G. Malyuga et al.
Establishing the optimal stand begins with choosing the seeding rate. One of the main tasks that agricultural producers have to solve is providing plants with an optimal nutritional area, which in turn directly determines the optimal standing density. According to V.A. Alabusheva, the optimal sowing rate for winter wheat is 5.0 million units. viable seeds/ha. When the seeding rate increases or decreases, the yield of winter wheat decreases, but at the end of the optimal sowing period, he recommends increasing the rate to 6.0 million pieces/ha. At the same time, a clear relationship has been established - with an increase in the seeding rate, the total and productive tillering decreases, and with a decrease in the seeding rate (up to 3.0 million units/ha) they increase. In practice, agronomists adhere to the following rule - the higher the soil fertility, the better the moisture supply and precursor, the less weediness - the lower the seeding rate, and vice versa - in more unfavorable conditions - they increase the seeding rate to the optimal one. I'M IN. Gubanov, N.N. Ivanov note that in modern conditions on farms, within one year, seeding rates can vary from 3.5 to 6.5 million units/ha.
Regarding the influence of sowing rates on plant resistance to lodging, all researchers are unanimous - increasing them leads to a decrease in resistance to lodging and an increase in the likelihood of lodging. However, there are few specific proposals taking into account the possibility of lodging. Some authors suggest observing optimal sowing rates and preventing thickening of the stem, while others recommend slightly lower sowing rates. More specific proposals are available regarding wheat sowing rates: 4.5-5.0 million viable seeds per 1 hectare or no more than 140 kg of seeds per 1 hectare. In each farm, the standards must also be adjusted taking into account the biological characteristics of the variety, the arsenal of means used to combat plant lodging, and the meteorological conditions of the year.
Thus, the seeding rate is determined by the given density of productive stems and the sowing qualities of the seeds; laboratory and field germination (laboratory germination is known, but field germination depends on the quality of the seeds, soil moisture and depth of seeding, etc.); the coefficient of productive tillering, which, in turn, is determined by the biological properties of the variety (potential tillering), the sowing period, on which the thermal resources of the autumn period of crop development depend, agrometeorological conditions of overwintering and spring-summer growing season, which determine the self-thinning of plants and stem selection.
It should be borne in mind that the predecessor has a certain influence on the formation of the stem and, consequently, on the seeding rate. An important factor in optimizing seeding rates is the variety’s ability to tiller. The realization of tillering energy in actual conditions depends primarily on the sowing period, which largely determines the density of productive stems and the seeding rate. The fact is that the ear is formed mainly by stems formed in the fall and undergone vernalization. Therefore, in late sowing crops, the grain yield is mainly formed by the ears of the main stem. Naturally, to obtain maximum yield, the seeding rate at later dates should be 12-15% higher.
Thickening of crops by increasing the seeding rate causes an increase in production costs and limits the realization of the potential capabilities of the variety. In such crops, field germination is reduced due to non-compliance with the minimum permissible distance between seeds in a row. During the tillering phase, self-thinning intensifies, and in the remaining plants the possibilities of developing productive stems deteriorate, since the nodal roots through which dying lateral shoots transmit their assimilates to the main stem are poorly developed or absent. As a result, the productivity of the main stem decreases. A related phenomenon during thickening is a deterioration in the phytosanitary condition of the crop. Ultimately, despite good conditions cultivation and high yield of above-ground mass, grain yield decreases. Thickening of sowing, in addition to the above, adversely affects the quality of grain, which is apparently due to a decrease in the feeding area and deterioration in the nutrition of individual plants.
High yields cannot be achieved without creating a good density of productive stems (for winter wheat, for example, 500-600 productive stems per 1 m2). However, it must be remembered that increasing the sowing rate only slightly increases the yield, since the increase in the number of productive stems is offset by a decrease in the number and weight of grains in the ear. In addition to increasing the likelihood of lodging, increasing sowing rates leads to an increased risk of disease and pests.
On each farm and on each field (taking into account fertility, topography, predecessors), the seeding rate is specified and changes depending on the timing and methods of sowing, moisture availability and other factors. In general, in agronomic practice there is a rule: the higher the field crop (fertility, moisture supply, predecessor, weeds, etc.), the less than normal seeding, and vice versa, in worse cultivation conditions, the seeding rate is increased within the recommended limits.
Analyzing changes in climatic conditions in the North Caucasus in recent decades, there is a need to review, improve, and sometimes change some elements in crop cultivation technology, such as sowing dates. Scientists such as A.I. paid special attention to the study of sowing dates. Nosatovsky, N.N. Borodin, F.M. Prutskov, V.N. Craft, H.G. Maluga, etc., because at different sowing dates the growing season conditions for winter crops are not the same: the amount of available moisture, day length, intensity of sunlight, temperature conditions, etc. These factors influence seed germination, growth and further development of plants, the depth of the tillering node, as well as the intensity and direction of physiological and biochemical processes that determine the resistance of winter crops to low temperatures and other winter factors. EAT. Lebedev found that in years that are favorable in terms of moisture, the timing of sowing winter wheat using non-fallow predecessors coincides with the timing of sowing using pure fallow, and in some years with a warm autumn, the sowing time can be shifted towards the winter period.
In the Rostov region, Professor A.I. Nosatovsky was the first to substantiate the optimal timing of sowing winter wheat, taking into account its developmental biology, requirements for growing conditions and overwintering conditions. Based on actual climate data of the first half of the 20th century, he calculated the best time for sowing winter wheat and recommended sowing it in the Azov zone of the Rostov region from September 5 to 15. According to our research, if in the 50s of the 20th century the autumn growing season of winter wheat plants lasted an average of 73 days, then in 2005 it was 12 days longer. The sum of positive air temperatures increased from 741°C (1950) to 830°C (2005). This meteorological fact requires clarification to determine the optimal timing of sowing winter wheat. If we look at the modern “Zonal farming systems of the Rostov region on a landscape basis, 2007”, they have not changed and the period of September 5-15 is recommended as the most optimal, although, as we noted, climate warming is occurring.
The timeliness of sowing is determined, in addition to thermal resources, by moisture reserves in the soil. In the southern regions of Russia, conditions of soil drought are often observed, which can cause delays in sowing, as a result of which such crops are not provided with sufficient heat. In this regard, the tasks arise of determining the extremely late dates for sowing winter crops and assessing the feasibility of sowing them later than these dates. When sowing late (September 20), more complete seedlings are obtained for both bare fallow and peas at different seeding rates of winter wheat compared to the recommended (September 10). Field germination of winter wheat seeds exceeded the recommended sowing period by 2-4%. This occurs due to greater accumulation of available moisture at the time of sowing winter wheat. Thus, for pure fallow at the recommended sowing time in the soil layer of 0-20 cm there was 23.9 mm of available moisture, which is 2.9 mm lower than the moisture content at a late sowing time; for peas there was 14.5 mm of moisture at the recommended time sowing and 18.7 mm - at a later date. The value of field germination was also influenced by the sowing rates of winter wheat seeds (Table 4.1).
According to T.JI. Maksimov and V.I. Ponomarev, the most favorable conditions for sowing winter wheat in areas of insufficient and unstable moisture are created when black or early fallow is used as a precursor. At the same time, the structure improves, fertility increases, the supply of soil with nutrients increases, due to mechanized labor, the weediness of the field and the phytoinfectious background are reduced, in addition, best conditions for the accumulation and conservation of moisture and nitrogen in the soil.
The positive effect of clean steam extends not only to winter wheat, having an aftereffect, according to Ya.V. Gubanov, they help reduce weed infestation and maintain high farming standards.
N.N. Borodin emphasized that the later the sowing is done, the shorter the fluctuations in the appearance of full shoots, and in moisture-rich years there is no particular difference in these values between pure fallow and the non-fallow predecessor. In dry years, seedlings in the latter case appeared only after rainfall. It is characteristic that it is for this reason that fluctuations in the indicated period after the non-fallow predecessor were reduced from early to late sowing dates.
The highest field germination rate for pure fallow was noted at a seeding rate of 4.5 million pcs/ha - 89%, and for peas - at a rate of 3.0 million - 71%. Thus, by comprehensively analyzing the seeding rates of winter wheat, as well as the sowing dates, it was established that the field germination of seeds depends directly on the availability of available moisture in the soil. In autumn, winter crops grow under gradually decreasing temperatures and shorter day lengths. Optimal sowing dates and favorable weather should provide all the basic requirements of plants.
He points out that in overgrown plants at the end of the autumn growing season, profound age-related changes occur, causing quantitative changes in the pigment system, expressed in lower content of chlorophyll and carotenoids throughout the subsequent period of autumn growing season until its cessation. In addition, aging, weakened plants of early sowing periods are often affected by pathogenic fungi. Therefore, after the resumption of vegetation, early crops are more thinned out, especially if there were unfavorable conditions during the overwintering period.
Of the works we reviewed, the issue of justification and development of methods for determining optimal sowing dates was studied in the most detail in the monographs of I.V. Svisyuk, which, in addition to generally accepted temperature conditions and moisture reserves in the soil, takes into account a complex of factors such as the potential bushiness of the variety, predecessor, optimal tillering, intensity of winter thaws, severity of winter, frost and winter hardiness of the variety. Studying the patterns of the tillering process as the basis for a method for determining the optimal sowing time, he notes the special importance of nitrification for this process: the more active the nitrification process, the more active the tillering is with the same potential tillering. In turn, nitrification activity depends on soil moisture, soil microflora and microfauna; in this case, the predecessor plays a significant role. Consequently, when solving the problem of optimizing the sowing time of winter wheat under the conditions of a specific field, it is necessary to take these factors into account.
A crucial time in the life of winter wheat is winter, when it has to overcome conditions that are often unfavorable in the region. In ordinary winters of the southern type with unstable snow cover, frequent thaws, followed by low temperatures, sometimes down to -30°C and below, and strong winds, the plants are thinned out to one degree or another.
Continuing the work of A.I., Nosatovsky, N.N. Borodin, based on experiments with new varieties of winter wheat, confirmed previously obtained data: plants that have time to bloom before the end of the autumn growing season are characterized by greater winter hardiness (and drought resistance), form an average of 3-4 shoots and a powerful root system. Plants that are sown late or germinate late due to dry soil in winter partially or even completely die. The remaining ones lag behind in development, tolerate drought worse, and often do not even form a satisfactory harvest. Early sowing plants also have disadvantages, especially during warm and long autumns. They outgrow, have a loose cell structure, contain more water than plants at the optimal sowing time, as a result of which they have a harder time withstanding low temperatures and temperature changes in winter, and drought in spring and summer. In addition, such crops are more susceptible to diseases and pests.
The safety of plants during the winter dormancy period is mainly determined by the degree of their development by the time the autumn growing season ceases and temperature conditions winter period. Before leaving for winter best development winter wheat plants of both predecessors had above-ground and underground parts at the recommended sowing time. Plants formed depending on the seeding rate for pure fallow: 5.6-5.8 stems and 13.3-13.7 secondary roots, for peas: 4.4-4.5 stems and 10.2-11.0 secondary roots (Table 4.2).
When sowing winter wheat in pure fallow at the recommended time, winter wheat plants vegetated for an average of 69 days, the sum of average daily air temperatures for this period was 619.4°C, and when sowing at a later date, the growing season was 10 days less, the sum of average daily air temperature - 458.2°C. The development of winter wheat sown over peas was less intense than under pure fallow due to slightly worse growing conditions, one of which is the low content of available moisture.
Full shoots when sowing at the recommended time were obtained after 15-16 days, after 11-14 days - when sowing at a later date - September 20. During the autumn growing season, winter wheat plants sown at the recommended time accumulated the sum of average daily air temperatures of 492°C sown late - 403°C.
V.D. Medinets found that low seeding rates, which create a lower initial plant density, will have an advantage in the formation of grain yield in years with early spring regrowth of plants, and high seeding rates, on the contrary, in years with a late resumption of spring vegetation.
Overwintering of winter wheat depends on many environmental factors, but the influence of most of them is directly dependent on the timing of sowing.
T.D. Lysenko, studying the freezing of winter crops, came to the conclusion that the main cause of plant death is loose soil. The less developed the plant and the looser the soil under winter crops before going into winter, the more likely the plants are to be damaged in winter. Rainwater fills voids in the soil. In winter, this water freezes, tearing the soil, and with it the young roots of plants, which leads to the death of the latter.
The same reasons explain A.I. Nosatovsky death of most of the late winter crops on late plowed Kuban chernozems, despite the fact that theoretically, the youngest plants should be the most resistant to frost, especially since their growth point is much deeper (at the seed itself) than that of plants , forming a tillering node. However, in agricultural practice, late sowings are still less resistant to low temperatures than sowings carried out at optimal times. The reason here is that late-sown winter crops have a small root system and it, as a rule, falls into the most loose soil, which leads to rupture of the roots when water freezes in the soil pores and to the death of plants. And, in addition, such plants are characterized by a weak ability to harden.
It should be noted that when sowing at a later date, the wheat was not overgrown, as a result of which, both for pure fallow and for peas, at all seeding rates, greater preservation of winter wheat plants was observed (Table 4.3).
The excess of the recommended sowing time over the options ranges from 2-9% (for pure fallow) to 1-3% (for peas). Thus, the best preservation of winter wheat plants after overwintering is ensured when 4-5 pieces are formed. tillering shoots and 10-11 roots of the secondary root system. To solve problems of agrometeorological forecasting, it is important to find indicators that sufficiently fully reflect the conditions of plant development.
Such indicators may include bushiness, number of stems and leaf area. According to A.A. Nichiporovich, crops that have an optimal structure, as well as the optimal course of its development and formation, should be considered those in which the relative leaf area quickly reaches a size of approximately 4.0-4.5 m2/m2 and for as long as possible (depending on the duration of the growing season period of a particular plant) remains in an active state at this level and, finally, decreases significantly or the leaves die off completely, donating plastic substances to the formation of reproductive or storage organs (Fig. 4.1).
Any changes in environmental conditions, to one degree or another, affect the development and condition of the assimilative apparatus and, above all, the size of the leaf surface, on which the overall productivity and yield depend. Therefore, one should expect a close relationship between yield and leaf area and, in particular, with its maximum, which is achieved before heading. IN optimal conditions development, a decrease in biological yield is observed only with leaf area > 5... 7 and even 10-11 m2/m2.
However, a decrease in economic yield begins, as a rule, at lower values, which is the result of mutual shading, leading to disruption of the normal course of morphogenesis associated with the formation of generative and productive organs, since these processes are light-dependent, as well as the result of the onset of lodging of thickened crops.
V.A. Kymakov, emphasizing the importance of the leaf area indicator, simultaneously points out that it is desirable that the value be more than 4 m / m, which can significantly lengthen the period of active absorption of PAR by crops. A.A. Nichiporovich believes that an increase in leaf area above 5 m2/m2 is negative, since at the same time the lighting conditions of the lower tiers worsen, their photosynthesis decreases, leaves begin to die, stems stretch, “fattening” and lodging of plants.
As our observations showed, in the spring tillering phase, winter wheat plants of late sowing with seeding rates of 3.0 and 6.0 million units/ha had a leaf surface area of 0.24-0.79 thousand m2/ha less, than plants sown at the recommended time (Table 4.4).
Starting from the boot phase, winter wheat plants of late sowing time in pure fallow at all seeding rates had the most developed leaf surface, compared to pea crops. The accumulation of dry matter by winter wheat plants is also closely related to the dynamics of the increase in leaf surface area (Table 4.5).
The amount of dry matter in pure fallow when comparing sowing dates was greater in the late variants for all sowing rates.
The difference in the booting phase was 11.8 g/m (4.5 million pieces/ha) - 17.8 g/m2 (6.0 million pieces/ha), by the waxy ripeness phase the difference was even more more noticeable - 32.9 g/m2 (3.0 million pieces/ha) - 63.8 g/m2 (4.5 million pieces/ha). For peas, these figures were somewhat lower: in the spring tillering phase the difference was 8.2-14.4 g/m2 (4.5 and 3.0 million pcs/ha, respectively), and by wax ripeness - 21.2- 43.3 g/m2 (6.0 and 4.5 million pieces/ha, respectively).
For the autumn development of winter wheat plants, it takes approximately 45-55 days when sowing in open fallows and 50-55 days in occupied fallows, with the sum of effective temperatures in the first case being 450-550°C, and in the second -510-550°C. The maximum required sum of temperatures, according to A.I. Nosatovsky - 580°C.
A more complex characteristic of the photosynthetic productivity of the assimilation apparatus, compared to leaf area, is the photosynthetic potential of the crop, proposed back in 1961 by A.A. Nichiporovich. It characterizes the productive capacity of a plant over different periods of time.
The timing of sowing had a noticeable effect on increasing the photosynthetic potential and increasing the net productivity of photosynthesis of winter wheat (Table 4.6).
In pure fallow, in winter wheat plants, regardless of the seeding rate, at a late sowing time, the photosynthetic potential was higher than the recommended sowing time by 61.4-94.1 thousand m2/ha day. For peas, at a seeding rate of 4.5 million units/ha, the photosynthetic potential of late sowing plants was less by 51.6 thousand m2/ha day, and when sowing at a rate of 6.0 and 3.0 million units/ha ha - more by 10.1-67.2 thousand m2/ha day. respectively.
PAR absorption depends on the size and intensity of leaf surface activity. According to I.I. Kovtun, plants at the optimal sowing time use PAR most sparingly, and with early or late sowing dates, to produce 1 kg of plant mass, approximately 30% more PAR is required compared to the consumption of the optimal period.
When analyzing the indicators of net photosynthetic productivity, we found that an increase in the sowing rate of winter wheat in pure fallow contributes to an increase in net photosynthetic productivity (Table 4.7).
For peas, with an increase in seeding rate, an increase in photosynthetic productivity can be traced only at the recommended sowing time, and at a later date, a decrease is observed at a seeding rate of 6.0 million units/ha to 1.97 kg per 1000 units of photosynthetic potential.
The efficiency of photosynthesis is determined not only by the total amount of dry matter, but also by the yield of its economically useful part. The coefficient of economic efficiency of photosynthesis is used as such an indicator, i.e. shares of biomass and energy of the total crop, concentrated in the economic part of the crop (Table 4.8).
We have established that at a seeding rate of 3.0 million units/ha, the coefficient of economic efficiency of photosynthesis of winter wheat for peas is higher than the indicators of similar options for pure fallow by 0.01-0.02; in other options, the coefficient of economic efficiency of photosynthesis is higher for options of late sowing period, in comparison with predecessors - according to pure fallow.
When analyzing the structure of the winter wheat harvest, the highest productive tillering was noted in variants with a seeding rate of 3.0 million units/ha with the recommended sowing time for both bare fallow (2.15) and peas (2.09). For pure fallow, the lowest indicators of productive tillering are observed at a seeding rate of 6.0 million units/ha -1.26, regardless of the sowing time (Table 4.9).
Thus, by changing the timing of sowing, it is possible to influence the provision of plants with solar radiation and heat, that is, in an indirect way to optimize the uncontrollable factors of plant life. Late sowing of winter wheat helps to increase the number of grains per ear by 0.3-0.9 pieces. for pure steam and 0.3-1.1 pcs. - for peas, and the weight of grain per ear increases by 0.02-0.04 g.
The difference in the mass of 1000 grains was not significant. We noted the highest indicators of biological productivity for pure fallow at a seeding rate of 4.5 and 6.0 million units/ha in late periods, and for peas - when sowing at a rate of 4.5 million units/ha in late periods.
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